Section 13 — Electrical

Induction Motors Above 500HP

IPE Engineering Practice IPE-EP-13-3-2

Document number: IPE-EP-13-3-2 · Section: 13 — Electrical

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SCOPE

This Practice describes horizontal and vertical squirrel cage induction motors, larger than 500 horsepower. Included as a part of this Practice are Data Sheets listing site information as well as the specific equipment requirements.

Only a service-proven design shall be offered. If a design is offered that has not been proven in service for at least two years, the proposal shall indicate which parts of the motor are affected (e.g., bearings, insulation, etc.) and the extent of experience with these parts.

This Practice is appropriate for attachment to an inquiry or purchase document when accompanied by the referenced IPE Engineering Practices and completed Data Sheets.

Any deviation from this Practice must be approved by the procedure described in EP 1-1-3. A revision bar indicates all changes made to this Revision.

REFERENCES

All applicable sections of the latest standards and codes listed below are a part of this Practice for design, construction and testing unless amended herein. It shall be the Manufacturer's responsibility to be or become knowledgeable of the requirements of the standards and codes. Any changes or alterations to the equipment to make it meet the requirements shall be at the expense of the Manufacturer.

STANDARDS AND PUBLICATIONS

STANDARDS AND PUBLICATIONS (Cont.)

DEFINITIONS

• Contractor - Company or business that agrees to furnish materials or perform specified services at a specified price and/or rate to the Owner.
• Inspector - A Inflection Point Engineering, LLC appointed engineer or inspector.
• Manufacturer - The recipient of a direct or indirect purchase order for materials and/or equipment. In this context, a direct order is one issued to a Manufacturer by a Contractor or the Owner. An indirect order is one issued to a Manufacturer by a vendor (recipient of a direct order) for materials, fabricated components, or subassemblies.
• Owner - Inflection Point Engineering, LLC.
• Owner's Engineer - A Inflection Point Engineering, LLC appointed engineer.
• Purchaser - The party placing a direct purchase order. The Purchaser is the Owner's designated representative.

SERVICE CONDITIONS

• Motors shall be designed for continuous outdoor operation without protective shelter, and they shall be adequate for withstanding long periods of inactivity, driven rain, salt-laden air, blowing sand, insects, fungus, snakes, and rodents. Unless otherwise noted on the Data Sheet, the motors shall be for use in a 104°F maximum ambient, -15°F minimum ambient and at an altitude of 3,300 feet or lower.
• When ammonia or H2S fumes are listed as an environmental condition on the Data Sheet, there shall be no exposed copper parts. All exposed parts shall be corrosion resistant. See paragraph 5.3.1.3 for further corrosion resistant part requirements.
• The motor and all its auxiliary devices (IEEE 303) shall be suitable for use in the specified classified area.

DESIGN, CONSTRUCTION AND MATERIALS

• General Performance Requirements
• Voltage and Frequency Variations
• Starting

Without injurious heating to any portion of the motor, the motor shall start and accelerate to running speed a load that meets the torque characteristics and inertia requirements of paragraph 5.1.2 within the voltage and frequency variation specified for the running conditions. For loads with other characteristics, the starting voltage and frequency limits may be different and will be specified on the Data Sheet.

• Running Conditions
• The motor shall operate successfully under running conditions at rated load with a variation in the voltage or the frequency up to the following:
• Plus or minus 10 percent of the rated voltage (with rated frequency).
• Plus or minus 5 percent of the rated frequency (with rated voltage).

• A combined variation in voltage and frequency of 10 percent (sum of the absolute values) of the rated values, provided the frequency variation does not exceed plus or minus 5 percent of the rated values.
• Performance within these voltage and frequency variations will not necessarily be in accordance with the standards established for operation at rated voltage and frequency.
• Load Requirements
• The motor load torque characteristics and total load inertia referred to the motor shaft shall be in accordance with NEMA MG1-20.42, unless specified otherwise.
• The motor and driven equipment manufacturer shall jointly assume responsibility for the proper starting and operating of the motor under load, including determination of load speed torque requirements for the proposed motor location at the Owner's facility.
• Starting Capabilities
• The motor shall be designed for across-the-line starting. However, reduced voltage starting may be necessary in special applications.
• Motors with rated voltage and frequency applied shall operate with the characteristics listed in Table 1 as a minimum requirement.
• The motor Manufacturer shall verify motor starting capabilities based on system and load characteristics given on the Motor Data Sheet and/or Driven Equipment Data Sheets.
• Performance: Motors shall operate with the following characteristics as minimum requirements with rated voltage and frequency applied:
• The maximum full-load slip shall not exceed 3 percent.
• In general, the maximum locked-rotor current shall not exceed 650%. Where this limit would have an adverse effect on other characteristics, the Manufacturer shall specify this effect and the preferred maximum current.
• The minimum locked-rotor, pull-up, and breakdown torques shall be no less than the values listed in NEMA MG1-20.41
• Full load efficiency as defined by IEEE 112 (Method B) shall not be less than:
• 200 to 1000 HP - 94%
• 1001 and above - 95%
• Power factor penalties for increasing efficiency shall be clearly stated.
• Service Factor: All motors shall be supplied with a 1.15 service factor, unless specified otherwise.
• Noise Levels
• Unless specified otherwise, the maximum (not average) sound pressure level (SPL) generated by the motor shall not exceed 85 dBA at three feet from the motor. Testing, machine loading and sound measurement shall be as defined by IEEE Standard 85.
• The Manufacturer shall provide evidence of compliance with noise limits for all proposed motors.
• The Manufacturer shall quote a standard motor with guaranteed maximum SPL 3 feet from the motor. Guaranteed level must be furnished (listed) on the Data Sheet. For motors that exceed specified limits, the motor Manufacturer shall separately quote the cost of special designs or acoustic treatment which would provide a guaranteed SPL to that specified. Details of special designs and or acoustic treatment shall be furnished with the proposal.

• Electrical Design Features
• Stator Windings:
• Self-balancing differential protection shall be provided for motors 1500 horsepower and above, unless specified otherwise on the Data Sheet. Both ends of each stator phase winding shall be brought out to the power lead terminal box that houses the differential protection current transformers. Current transformer ratio shall be 50:5. All leads shall be insulated for full voltage.
• The motor shall be braced for full-voltage starting, unless otherwise specified.
• Insulation System
• Unless specified otherwise, all motors shall have Class "F" non-hygroscopic insulation systems, including leads and connections to the windings. When bus bars are used, they shall be insulated. The thermal rating of the coil connections shall be equal to that of the coil.
• All stator coils shall be secured tightly in their slots. The winding end turns shall be adequately braced and supported to withstand the starting capabilities as indicated in paragraph 5.1.3.
• Motors with a 1.15 service factor shall have Class F insulation with a Class F temperature rise by resistance at 1.15 loading factor. Motors specified as 1.0 SF shall have Class F insulation and a Class B temperature rise by resistance at 1.0 loading factor.
• The stator insulation system shall be highly moisture and chemical resistant. All parts used to form the insulation system shall be non-hygroscopic. The insulation integrity shall be maintained while withstanding the operating forces, and thermal stresses at Class F temperatures without damage.
• All stator insulation systems shall be service proven and shall have been subjected to a thermal evaluation in accordance with IEEE 429.
• All insulation systems shall be impervious to all commonly encountered contaminants in petrochemical environment. In addition, they shall withstand any special operating conditions specified on the Data Sheet.
• All motors shall have a sealed insulation system (NEMA MG1-1.27.2). The insulation method shall be premium grade, mica glass/polyester fiber backed tape or mica flake (mica flake paper wrapper), epoxy resin, vacuum impregnated (VPI) and cured. Stator windings shall be given a minimum of two VPI cycles.
• All stators shall have sealed insulation systems that are capable of withstanding an immersion test in accordance with NEMA MG1-20.49.
• Stator leads with rubber based insulation such as EPR shall be jacketed, taped or sleeved with an oil resistant material such as PVC.
• If a two speed motor is specified, a two (2) winding motor shall be provided. If a two winding motor is not technically feasible, an alternate design can be offered along with a detailed justification.
• Motors to be used in conjunction with adjustable frequency drives (AFD) shall have a Dacron glass insulation turn-to-turn rated to withstand the AFD output voltage peaks etc.
• When abrasive dust conditions has been specified on the Data Sheets, the electrical insulation shall have additional protection for protection from the abrasive action of the airborne particles. The protective measures shall require approval by the Owner.

• Mechanical Design Features
• Enclosures
• Enclosure parts may be made of cast iron, cast steel, sheet steel, or steel plate. Owner approved reinforced plastic may be used for parts such as covers or non-supportive enclosure sections. These parts shall have rigidity (mechanically) equivalent to 1/8 inch sheet steel.
• Air deflectors shall be made of corrosion-resistant material or have corrosion-resistant plating or treatment suitable for the environmental conditions.
• All hardware, bolts, studs, piping, and other fastening devices of the enclosure shall be made of series 300 stainless steel.
• The enclosure shall be designed to facilitate cleaning and painting of the motor interior.
• The impact of potential risks due to possible circulating currents in the enclosure should be considered for motors using multi-section enclosures installed in classified locations. Overheating or sparking due to possible circulating currents shall be avoided, where necessary, by securing together the conducting components in a sound electrical and mechanical manner, or by the provision of adequate bonding straps between the motor housing components (See NFPA 70-1999 paragraph 501-8 (FPN No. 2)).
• Stator
• Stator Housing (Frame):
• The frame shall be of cast or nodular iron, cast steel or welded steel plate construction with removable end bells or end plates to permit removal of the rotor and facilitate replacement of stator coils. The frame of the completely assembled machine with the rotor installed and rotating on its oil film, shall be free from structural resonance within ±5 percent of electric line frequency and twice line frequency and the following frequency ranges N where N = (nNop ± 0.20 Nop) and Nop equals the operating speed and n = 1,2, and 3.
• The stress values used in the design of the frame shall not exceed the maximum allowable stress criteria specified in Section VIII, Division 1, of the ASME Boiler and Pressure Vessel Code (commonly called the ASME Code) for materials used. Conditions evaluated should include short circuits, out-of-phase re-energization (plug-reversal), thrust, handling, and specified seismic loading.
• The motor frame, including bearing supports, shall be designed to have sufficient strength and rigidity to limit changes of alignment caused by the worst combination of torque reaction, conduit/piping (motor manufacturer supplied only) stress, magnetic imbalance, and thermal distortion to 0.002 inches at the coupling flange (This is not to be confused with the normal repeatable thermal growth between ambient and operating temperatures).
• Frames on horizontal motors shall be rigid enough to permit the machine to be moved by using the lateral, axial, and vertical jack screws.
• Horizontal motors shall be equipped with vertical jackscrews appropriately located to facilitate coupling alignment. When sole plates are provided (specified) they shall be supplied with lateral and axial jack screws. If size and weight prohibit the use of jackscrews, other provisions shall be made for vertical jacking.
• Frame mounting surfaces on horizontal motors shall be machined on a common plane parallel to a horizontal plane through the motor's theoretical centerline. The mounting surfaces shall be machined within 0.005 inch of a plane through the lowest foot, and each foot shall be parallel to that plane, in the transverse or longitudinal direction, within 0.002 inch per foot.

• The mounting surface of vertical motors shall be machined perpendicular to the motor centerline, and this surface shall not deviate from that perpendicular plane by more than

0.002 inches per foot.

• The motor frame mounting surface tolerance for unlevelness shall be a maximum of 0.001 inches per foot.
• The machined finish of the mounting surface (sole plate and motor frame) shall not exceed 250 microinches arithmetic average roughness (Ra) or better. Hold-down or foundation bolt holes shall be drilled perpendicular to the mounting surface or surfaces and, when the mounting surface is a cast or other unmachined, uneven surface, spot face to a diameter three times that of the hole diameter.
• Sole plate tolerance for unlevelness shall be a maximum of 0.002 inches per foot.
• Mounting sole plates shall be large enough to provide ample space for easy placement of a precision machinist's level, Starrett 98 or equal. Space shall be provided on all equipment footpads/mounting surfaces in both directions for leveling purposes.
• Lifting lugs, through holes, or eyebolts shall be provided for lifting major components and the assembled motor. Any special mechanisms for lifting major components and the assembled motor shall be identified by the Manufacturer and priced as a separate line item in the quotation.
• All fabricated welded structural steel shall be post-weld stress relieved.
• When sole plates are to be grouted with epoxy grout, the sole plate grout areas (surfaces) shall be sandblasted in accordance with SSPC SP6. All sandblasted mounting surfaces shall be pre-coated with a catalyzed epoxy primer that is applied to degreased white metal. The epoxy primer shall be compatible with the Owner's epoxy grout.
• Stator Core
• The stator core shall be built-up from laminations of low loss high permeability type steel. These laminations are to be deburred and insulated to reduce eddy current losses.
• The stator lamination core plate shall be of at least C-5 or C-6 quality per ASTM A345. C-3 shall not be used, even along with C-5 or C-6. The stator core shall be capable of withstanding winding burnout for rewind at 750°F without damage or loosening.
• Rotor/Shaft System
• The rotating element shall be constructed to withstand the starting duties in paragraphs 5.1.3 and have a fatigue life of at least 5000 full voltage starts.
• Shaft type and material shall be either forged steel shaft or rolled steel shaft as specified on the Data Sheet:
• Forged Shaft
• Forged shafts shall be one-piece, heat-treated, forged steel suitably ground. Suitable fillets shall be provided at all changes in shaft diameters and in keyways. The preferred shaft material is AISI 4140 grade. However, AISI 4150, 4130 and 1045 are acceptable as the application warrants.
• The shaft shall be ultrasonically inspected prior to assembly.
• Shaft end at coupling fits shall conform to the requirements of API 671.
• Welded shaft and bar shaft/spider construction is not permitted on two-pole machines with heat treated forged steel rotors.
• Rolled Steel Shaft
• Shaft shall be 1040, 1045 or 4150 hot rolled steel.

• Shaft end at coupling fits shall conform to the requirements of API 671.
• Rotor
• Rotor laminations shall have no burrs in excess of 0.003 inch (0.075 millimeter) and shall be distributed to prevent uneven buildup and to evenly distribute magnetic properties in grain orientation. The method of assembly shall prevent shaft surface scoring, assure positive positioning, and minimize bowing.
• All rotors shall be fabricated with copper/copper alloy bars and end rings.
• When specified on the Data Sheet, motors up to and including 750 HP may be supplied with cast aluminum rotors. When cast aluminum rotors are provided, rotors shall be tested for voids. A copy of the test procedure shall be supplied with the quotation for owner review. Certified as Manufactured test data for voids shall be supplied with other testing data requirements in Section 7.3.
• End rings without circumferential joints are required for motors having synchronous speeds of 1500 RPM and higher and are preferred for slower speed motors. Jointed end rings are permitted for slower speed motors with the Owner's Engineer's approval.
• All bars shall be maintained tight in the slot to limit vibration and fatigue. The rotor cage shall be maintained center locked (swedged, centered, pinned). An alternate design is acceptable which uses a floating cage construction in which the cage is pinned to the center of the rotor to stabilize the rotor and permit uniform thermal expansion of the cage.
• The method of attachment of the bars to the current-carrying end ring shall be selected to minimize localized heating and the non-uniform stresses that result. The bars shall be radially supported as necessary in the current-carrying end ring to prevent the braze or weld from being overstressed. The metal joining material shall not be subject to attack by hydrogen sulfide (that is, phosphorus-free material). Inert gas welding, induction brazing and multi-torch full circle brazing are acceptable methods. Outward bending of rotor bar ends and shorting ring articulation shall be limited by design, material selection, or shrunk- on nonmagnetic steel retainer rings.
• End rings and bars shall be replaceable without damage to air passages or laminations.
• Copper/copper alloy bars and end-ring material and processes shall be selected to minimize hydrogen embrittlement.
• Rotors shall be designed to withstand overspeeds per NEMA MG1-20.44 without permanent mechanical deformation.
• It is preferred that fans be separately mounted and not integrally cast with the end rings. Other Manufacturer's standard methods for fan mounting/attachment may be offered to the Owner for consideration and approval. Separable fans shall be permanently indexed angularly and axially and mounted by one of the following methods:
• Spider hub on shaft.
• Split hub on shaft.
• Shrink-fit on shaft.
• Removal and reassembly of the fans to the rotor shall not change the rotor balance outside the allowable residual unbalance limits. Slip-fit fans secured only with set screws to the shaft are not acceptable.
• Fans shall be capable of being balanced in accordance with paragraph 5.3.4 of this Practice.
• Unless specified otherwise, all 2-pole (3600 rpm) motors and all other speed motors greater than 900 HP, shall be supplied with provisions for non-contacting vibration probes.

• All keyway cuts shall have a radius to reduce stress concentrations. The bottom corners of all keyway radii shall be at least one-eighth of the keyway depth.
• Balance
• Motors shall be dynamically balanced. The use of solder or similar deposits for balance correction shall not be acceptable. Any parent metal removed to achieve dynamic or static balance shall be drilled out in such a manner as to not affect the structural strength of the rotor. Rotor balancing shall not be accomplished by adding balance weights on the fan blades. Chiseling or sawing shall not be permitted. Balance weights added to the final assembly shall be Series 300 stainless steel or an equivalent corrosion-resistant material.
• Rotors with single keys for couplings shall be balanced with a half key in place. The half key used for balancing shall be dynamically equivalent to a half key which completely fills the keyway. A crowned half key is preferred.
• All rotors shall be dynamically balanced in two or more planes. When specified on the Data Sheet, flexible shaft rotors shall be balanced in a minimum of three planes, including a rotor center plane.
• After final balance of the main rotor, the fans and any other removable rotor components shall be installed and component (step) balanced. Corrections for balance after installation of the fans shall be made on the fans only.
• Unless specified otherwise, the Owner's balanced coupling shall be mounted by the motor Manufacturer and the rotor balance re-checked. Any increase in unbalance shall be reported to the Owner. Any changes to the rotor or coupling balance shall be mutually agreed to by the Owner and Manufacturer.
• For the final balancing of the rotor in the balancing device, the maximum allowable residual unbalance in the correction plane shall be calculated from the following equation:

where:

U B = Residual unbalance, in ounce-inches

Wr = Journal static loading, determined from the mass distribution in the rotor, in pounds. (Typically one-half rotor weight).

N me = Maximum continuous speed, in revolutions per minute

• A balancing device is either a conventional balancing machine or the actual motor frame assembly with rotor installed. Where the motor frame is used as a balance device, the residual unbalance of the rotor shall be determined in accordance with API Standard 541 Edition Three, Appendix C.

• When non-contacting radial vibration and/or axial-position probes are furnished, or when provisions for probes are required, the rotor shaft sensing areas to be observed by radial- vibration probes shall be concentric with the bearing journals. All shaft sensing areas (both radial vibration and axial position) shall be free from stencil and scribe marks or any other surface discontinuity, such as an oil hole or a keyway, for a minimum of one probe-tip diameter on each side of the probe. These areas shall not be metalized, sleeved, or plated. The final surface finish shall not exceed 32 microinches Ra, preferably obtained by honing or burnishing. These areas shall be properly demagnetized or otherwise treated. For areas to be observed by radial vibration probes, the combined total electrical and mechanical runout shall not exceed 30% of the maximum allowed peak-to-peak unfiltered vibration amplitude (refer to Table 3 ), or the following value whichever is greater:
• For areas to be observed by radial-vibration probes, 0.25 ml.
• For areas to be observed by axial-position probes, 0.5 mil.
• When specified, the driven-equipment Manufacturer, the motor Manufacturer, or both shall perform a steady-state and transient torsional and stress analysis of the motor and driven equipment, including gears, motor-driven pumps, and fan- or turbine-assisted units. The driven-equipment Manufacturer shall be responsible for the complete and satisfactory performance of the units. The motor Manufacturer shall be responsible for providing the physical data required for the torsional analysis to the Purchaser or driven-equipment Manufacturer as specified and in a timely manner to allow for any system modification that might be necessary. The torsional analysis shall include but shall not be limited to the following:
• A complete description of the method used to complete the analysis.
• A graphic display of the mass-elastic system.
• A tabulation identifying the mass moment and torsional stiffness for each component identified in the mass-elastic system.
• A graphic display or expression of exciting pulsating torque or other torsional excitation versus speed or time.
• A graphic display of torsional critical speeds and deflections (a mode shape diagram).
• The torsional analysis (when torsional analysis is specified) shall confirm that the frequency of the torsional modes of the complete motor-driven train is at least 15 percent removed from any important excitation frequencies and both one and two times the line frequency. For trains with adjustable-speed drivers, the operating speed includes operation up to the trip speed. If this requirement cannot be achieved, calculations shall be made to determine the maximum stresses, the frequency at which they occur, and the fatigue life of each element in the train. These calculations should be given to the Owner and to the driven-equipment Manufacturer, the motor Manufacturer, or both for approval. The torsional analysis shall also verify that the calculated shaft torque at the resonance points during run-up does not exceed five times the rated motor torque, based on a motor air-gap torque related to a full-voltage start. For adjustable speed drives, the torsional analysis shall also verify that the calculated shaft torque at the resonance points up to the maximum operating speed does not exceed the allowed maximum stress.
• Resonances
• Resonance response peaks of the motor shall be at least 15 percent removed from the operating speed plus or minus slip or any other forcing frequencies.

• For all 3600 RPM motors with flexible shafts, and other motors as specified:
• The Manufacturer shall include with the proposal an undamped critical speed map that is typical of the motor being offered.
• After receipt of the order the Manufacturer shall provide a damped critical speed map and an unbalanced response plot (the amount of unbalance shall be equal to the maximum allowable residual unbalance) for the motor being offered.
• Vibration
• The radial vibration levels measured on a bearing housing with the machine operating at rated voltage and frequency at any loading up to service factor loading shall not exceed the limits presented in Table 2.
• The maximum unfiltered and filtered shaft displacement relative to the bearing housing, with the machine operating at rated voltage and frequency at any loading up to service factor loading, shall not exceed the limits given in Table 3.
• Motors that do not have non-contact vibration probes or provisions for probes, the bearing housing vibration limits are as given in Table 2. A shaft-rider is not an acceptable substitute for non-contact vibration probes when non-contact vibration probes or provisions for vibration probes are specified. When non-contact vibration probes are specified, they shall be used for certified test data. When provisions for non-contact probes are required, shop probes shall be used for vibration measurements and shall meet the accuracy requirements of API 670.
• Vibration Probes: When specified on the Data Sheet, non-contacting vibration probes and/or provisions for shall be supplied, located and mounted as follows:
• Horizontal Motors: Two radially oriented probes shall be provided (or provisions for) for each
• Vertical Motors: Two axial position probes shall be provided (or provisions for) for the hydrodynamic thrust bearings.
• Each probe lead and extension shall be plainly marked with stainless steel tags to indicate the probe location and service.
• All rigid conduit used for extension cables shall be listed rigid galvanized steel (RGS).
• Flexible conduit used at probes to RGS transition shall be listed liquid tight flexible conduit. The length, 3/4 inch minimum, of the flexible conduit shall be minimized to facilitate maintenance and device removal.
• A gasketed, stainless steel, junction box shall be provided outside the machine, as a make up box, for all cable connections and vibration equipment devices to facilitate servicing while the machine is running (Other corrosion resistant junction box materials maybe supplied with approval of the Owner).
• If required, the proximiter housing enclosure shall be a gasketed fabricated stainless steel box (other corrosion resistant junction box materials may be supplied with approval of the owner).
• Enclosures and Corresponding NEMA Specifications
• Requirements for Weather-Protected Type I Motors (WP-I):
• Weather-protected Type 1 motors shall conform to NEMA MG1-1.25.8.1.

• All internal parts of the motor exposed to the cooling air, such as air deflectors, and fans, shall be made of non-sparking, corrosion resistant material or have corrosion resistant platings or treatments.
• Drain holes shall be provided at all locations in the enclosure where water might collect.
• All oil piping, bolts, studs, other fastening devices, and balance washers of the motor shall be made of corrosion resistant 300 Series stainless steel.
• WP-I type enclosures shall be constructed to include provisions for inlet filters.
• When specified, inlet filters shall be provided.
• When abrasive-dust conditions have been specified on the Data Sheets, electrical insulation shall be protected from the abrasive action of airborne particles.
• Requirements for Weather-Protected Type II Motors:
• Weather-protected II Type motors shall conform to NEMA MG1-1.25.8.2.
• All ventilation openings and passages shall be contained within the motor enclosure. Motors shall be suitable for mounting on conventional foundations or bedplates.
• Enclosures shall be designed to facilitate rust removal and spray painting of the motor interior without breaking any welded joints.
• Drain holes shall be provided at all locations in the enclosure where water might collect.
• Terminal boxes shall be gasketed/watertight NEMA 4. These boxes shall be made of cast iron, cast steel, sheet steel, or steel plate, and shall have hubs or threaded openings for rigid conduit. Boxes made of sheet steel or steel plate shall have a minimum wall thickness of 1/8 inch. Cast motor terminal boxes shall be diagonally split and rotatable in 90° turns.
• Motor terminal boxes shall be oversized to allow for routing of incoming power cables, stress cones and additional equipment as specified. Provide drains in low areas where condensation may collect.
• All bolts, studs, other fastening devices, and balance washers of the motor shall be made of corrosion resistant 300 Series stainless steel.
• Paragraph 7 of paragraph 5.3.8.1 is also applicable.
• All weather protected Type II motors shall be provided with filters per Paragraph 5.4.5.
• Requirements for Totally Enclosed Water Air Cooled Motors:
• Totally enclosed water air cooled motors shall conform to NEMA MG1-1.26.7.
• Cooling water temperature, pressure, fouling factor shall be specified on the Data Sheet.
• The heat exchanger shall be of double tube construction and mounted on top of the motor.
• The interior of the motor shall be baffled or otherwise constructed to prevent water from cooler tube leaks directly striking the motor windings. The design shall assure that water from cooler leaks will collect and drain from the motor before reaching the level of the windings.
• The annular space between tube walls of double tube coolers shall be drained to an inspection point outside the cooler housing. An enclosed float switch, with alarm contact for the Owner's use, and collecting pan shall be provided and mounted externally on the motor housing. The switch enclosure shall be suitable for the specified area classification of the motor location.
• Motors shall have provision to accept a purge gas from an external source when specified on the Data Sheet. Shaft seals shall be designed to minimize leakage. The maximum purge pressure and air leakage rates shall be provided to the Purchaser.
• Paragraphs 3, 4, 5, 6, 7 and 8 of Paragraph 5.3.8.2 are also applicable.

• Other Enclosures: Drip-proof and other Data Sheet specified enclosures shall conform to applicable NEMA standards and requirements noted on the Data Sheet.
• Painting

All exterior and interior frame metal including accessory box interiors shall be finish painted with a quality severe duty epoxy paint the motor manufacturer's standard color unless specified otherwise.

• Bearings and Bearing Housing
• Unless otherwise specified, hydrodynamic radial bearings with oil rings shall be provided on all horizontal motors.
• Antifriction bearings shall be used for vertical motors and when specified for horizontal motors, providing that the following conditions are met:
• Where the dN factor is less than 300,000 [The dN factor is the product of bearing size (bore) in millimeters and the rated speed in revolutions per minute].
• For horizontal motors, a standard anti-friction bearing shall meet an L10 rated life of either 100,000 hours with continuous operation at rated conditions, or 50,000 hours at maximum axial and radial loads and rated speed (The rated L 10 life is the number of hours at rated bearing load and speed that 90 percent of a group of identical bearings will complete or exceed before the first evidence of failure). See AFBMA Standards 9 and/or 11.
• Anti-friction bearings used in vertical motors shall have as a minimum an L10 rating life (per AFBMA Std 9 and 11) of at least 100,000 hours. Bearings shall also give a minimum L10 rating life of 50,000 hours when carrying the maximum loads (radial or axial or both) imposed with internal pump clearances at twice the design values when operating at any point between minimum continuous stable flow and rated flow.
• Horizontal and vertical ball bearing and roller bearing manufacturing tolerance limits shall be in accordance with ANSI/AFBMA 20-1987, Table 4 (ABEC1-RBEC1).
• Bearings shall not have filling slots. Bearings for horizontal motors shall have a C-3 loose fit as defined by AFBMA Standard 20.
• Hydrodynamic radial bearings shall be split (not applicable to double-shell, totally enclosed,

fan-cooled enclosures) for ease of assembly and shall be of the precision-bored-sleeve or pad type, with cast iron, steel, or bronze backed babbitted replaceable liners, pads, or shells.

Bearings shall be equipped with anti-rotation devices and shall be positively secured in the axial direction. The bearing design shall suppress hydrodynamic instabilities and provide sufficient damping to limit rotor vibration to the maximum specified amplitudes while operating loaded or unloaded at specified operating speeds, including operation at any critical frequency if that critical frequency is a normal operating speed. The liners, pads, or shells shall be horizontally split housings and shall be replaceable. The bearing housing design shall not require removal of the lower half of end bells or plates, duct work, or the coupling hub to permit replacement of bearing liner, pads, shells, rings and seals.

• Ball-type thrust bearings shall be of the duplex-matched, single-row, 40-degree, angular- contact type (Series 7000) installed back to back.
• Thrust bearings for vertical motors shall be on top and preloaded and be either a single bearing or a duplex tandem bearing. Tandem bearing assemblies shall require approval by the Owner.

• Bearing housings for hydrodynamic bearings designed for pressure lubrication shall be arranged to minimize foaming. The drain system shall be adequate to maintain the oil and foam level below the shaft end seals and allow sufficient oil level for oil slinger disk(s) or oil ring(s) operation. Oil temperature rise for all hydrodynamic bearings shall not exceed 50°F under the most adverse specified operating conditions when inlet oil temperature is 110°F. Where inlet oil temperatures exceed 120°F, special consideration shall be given to bearing design, oil flows, and allowable temperature rise.
• Bearing housings for horizontal motors shall be equipped with split, labyrinth-type end seals and deflectors where the shaft passes through the housing. Lip-type seals shall not be used. Deflectors shall be made of nonsparking materials. The labyrinth deflector design shall effectively retain oil in the housing and prevent entry of foreign material into the housing. No oil shall leak past the seal into the interior of the machine. For horizontal anti-friction bearing motors, In Pro seal bearing insolators shall be supplied on the drive end, outboard for (WP I, WP II) and on both ends for TEFC enclosure motors.
• Housings for ring-oil-lubricated bearings shall be provided with plugged ports positioned to allow visual inspection of the oil rings while the equipment is running.
• Anti-friction bearings shall be retained on the shaft and fitted into housings in accordance with the specifications of AFBMA Standard 7. However, locking of ball thrust bearings to the shaft shall be restricted to a tongue-type lockwasher, for example, Series W of AFBMA Std 8.2.
• Anti-friction bearings, except for the angular-contact type, shall have a loose internal clearance fit equivalent to AFBMA Symbol 3 (AFBMA Std.20) as a minimum. Single-row or double-row bearings shall be of the Conrad type. Filling-slot (maximum load) anti-friction bearings shall not be used. Bearing housing mounting surfaces shall be flat and in the same plane, machined perpendicular to or parallel with the bearing bore, as required.
• Bearing housings on motors, except totally enclosed, fan-cooled motors, shall be positively located by cylindrical precision dowels or rabbet fits. Bearing housings and support structures shall be designed so that, upon assembly, none of the air-gap measurements taken in at least three positions each (9,12, and 3 o'clock) at both ends of the motor deviates from the limit given below, as defined by the following equation:

Where:

D = percent deviation.

H = the highest of the three readings at one end. L = the lowest of the three readings at that end. A = the average of the three readings at that end.

• The air gap between the exterior of the rotor and the interior of the stator must be measured at both ends of the motor. Measurements shall be taken at the positions defined above. The percentage deviation shall not exceed 10 percent. This data is to be recorded and made part of the final report. NOTE: Stator surfaces at the measuring positions shall be free from resin buildup to allow for accurate measurement.
• All non-drive end bearings shall be electrically insulated. When specified on the Data Sheet, both bearings shall be insulated. For double-end drivers, the (ODE) and the (DE) shall have insulated bearings. If both ends are insulated, a shorting device shall be provided in the drive end bearing housing.
• Hydrodynamic thrust bearings for vertical motors shall be of the babbitted multiple-segment type. Tilting-pad-type bearings shall incorporate a self-leveling feature assuring that each segment carries an equal share of the thrust load. The thrust collar shall be replaceable. Fretting and axial movement shall be prevented either by positively locking the collar to the shaft or by other methods. The thrust faces of the collar shall have a surface finish not exceeding 16 microinches root mean square, and the total indicated axial runout of either thrust face shall not exceed 0.0005 inch. Split thrust collars are not acceptable.
• Hydrodynamic thrust bearings for vertical motors shall be sized for continuous operations under all specified conditions and selected at no more than 50 percent of the bearing Manufacturer's rating. In addition to thrust from the rotor, the maximum axial force from the driven equipment transmitted through the coupling shall be considered a part of the duty of any thrust bearing.
• At ambient temperature conditions, the fit between the outside of the bearing shell and the bearing housing shall be line-to-line (zero clearance) and shall preferably be a light interference fit.
• Lubrication Systems
• For all oil lubrication systems, the bearing housing shall have reservoirs of sufficient depth to serve as settling chambers. The housings shall each be provided with 1/2 inch minimum national pipe thread (NPT) tapped-and-plugged, fill and drain openings. Non-pressurized systems shall be equipped with 8-ounce minimum size constant-level sight-feed oilers with a positive level positioner (not a set screw), transparent containers (not subject to sunlight or heat-induced opacity or deterioration), and protective wire cages and supplemental support in

addition to the piping. A permanent indication of proper oil level shall be accurately located and clearly marked on the outside of the bearing housing with permanent metal tags, marks inscribed in the castings, or other durable means. In case of accidental breakage of the oil level indicator, a drop in oil level shall not result in loss of bearing lubrication, i.e., oil level reduction below level required for oil ring operation. The oil system shall have sufficient surge capacity to absorb, without overflowing, all oil returned from the bearings when the motor is stopped.

Bearing housing shall be fitted with fill and drain openings and the necessary slingers, equalizers, vents, or other devices to prevent loss of lubricant.

• Oil for motors requiring forced-feed lubrication shall be supplied from the driven equipment lubrication system, if a suitable system is available. In this case:
• The motor Manufacturer shall specify his oil flow, pressure and quality requirements, and the heat rejection rate.

• Supply oil rings for start-up and emergency operation and designed to allow for orderly shutdown in the event of forced feed system failure.
• All oil piping will be furnished by the driven equipment vendor. Piping shall meet the same specifications as the driven equipment piping. Sight flow indicators for each bearing and a flow or pressure switch shall also be provided.
• When a forced-feed lubrication system is supplied with the motor, the system shall conform to EP 6-9-1 and include:
• A shaft-driven or separate motor-driven pump.
• An adequate lube oil cooling system.
• Oil rings for start-up (motors with shaft-driven pumps) and emergency operation.
• Duplex filters to permit change without shutdown.
• A pressure controller and a bypass relief valve if the oil pump is of the positive- displacement type.
• A pressure gauge upstream and downstream of the filter, dial thermometer to indicate oil temperature, sight flow indicators for each bearing, and a flow or pressure switch.
• Oil level indicators for each bearing housing.
• An observation port for visual check of rotation of oil ring.
• The following conditions apply when oil mist lubrication is specified for anti-friction bearings:
• An oil mist inlet connection, NPS 3/8 inch, shall be provided in the top half of the bearing housing. The pure or purge mist fitting connections shall be located so that oil mist will flow through the anti-friction bearings.
• A vent connection, NPS 1/2 inch, shall be provided on the housing or end cover for each of the spaces between anti-friction bearings and the housing shaft closures.
• When pure or purge oil mist lubrication is specified, shielded or seal-type bearings shall not be used.
• When pure oil mist lubrication is specified, oil rings or slingers (if any), a constant level oiler and a mark indicating oil level are not required.
• The motor Manufacturer shall furnish insulating fittings in the oil supply connections to prevent the oil supply lines from bypassing the bearing insulation.
• Sufficient cooling, including an allowance for fouling, shall be provided to maintain oil temperature below 160°F for pressurized systems and below 180°F for ring-oiled or splash systems based on specified operating conditions and an ambient temperature of 140°F. Where water cooling is required, water jackets shall have only external connections between the upper and lower housing jackets and shall have neither gasketed nor threaded connection joints, which may cause water leakage into the oil reservoir. Cooling coils (including fittings), if used, shall be of Series 300 stainless steel and shall have no internal pressure joints or fittings. Coils shall have a minimum thickness of 0.042 inch and a minimum diameter of 1/2 inch.
• End Play and Coupling
• Horizontal sleeve-bearing motors shall have a total end play of at least 1/2 inch. Provide a factory-set magnetic center indicator device. The running center of the rotor shall not shift from the geometric center of the rotor's total end play by more than 3/32 inch.

• Flexible couplings used with horizontal sleeve-bearing motors will be of the limited-end float type with the end-float restricted to not more than 3/16 inch. The Manufacturer will be advised of the exact float of the coupling used.
• When the limited end float coupling is used, the motor shall have a permanent indicator (or indication) to show the magnetic center and allowable limits (both ends of the float) of shaft movement after coupling installation and alignment. The indication method shall be durable and be adjacent to a shaft shoulder, and shall show the allowable excursion of the shoulder (e.g., scribe on shaft, or a notch, with a stainless steel pointer). It is preferred that scribe marks are used on the shaft to show end float limits and magnetic center.
• Cylindrical interference fit shall be in accordance with AGMA 9002.
• Taper fit motor couplings shall be in accordance with API STD 671.
• The purchaser of the coupling shall supply an idling adapter, as required for the mechanical running test. Testing with the contract coupling is required. If it is not practical (with approval of the Owner), the mechanical running test shall be performed with a coupling and coupling hub idling adapters in place, resulting in moments equal (± 10 percent) to the moment of the contract coupling hub plus one-half that of the coupling spacer. When all testing is completed, the idling adapters shall be furnished to the Owner as part of the special tools.
• Shaft Seals: Frame shaft seals shall be of non-sparking materials, shall be the split type to allow replacement without removal of the rotor or coupling, and shall be centerable about the shaft. Where aluminum is used it shall have a copper content of less than 0.2 percent. Where endshield-supported bearings are used, the inner seal shall be maintained at atmospheric pressure. Pressure balancing from the cooling fan shall be by use of copper or steel tubing, unless other materials are approved by the Owner. Seals shall be designed to minimize the entry of fumes, dirt, and other foreign material into the stator housing. When specified, seals shall be constructed such that a purge gas can be introduced. If possible, self aligning seals shall be used.
• Marking of the Terminal Leads: The method of marking leads shall be permanent - suitable for the life of the motor. Leads shall have at least one identification marker within 6 inches of the exterior of the stator frame.
• Piping flanges shall conform to ASME STD B16.5. Tapped openings and bosses for pipe threads as well as machined and threaded connections shall conform to ASME STD B16.5.
• Accessories
• Nameplates
• General Construction: All nameplates shall be of stainless steel construction and securely attached to the motor by means of stainless steel screws.
• Data: Motors shall be equipped with nameplates containing information required in NEMA MG1-1.21.61 plus:
• Manufacturer's data: Type of enclosure, and frame size.
• Mechanical data: The oil level measured from the base of an oil ring (I.D.) for lubricated sleeve-bearing motors provided with constant level oilers, the oil pressure required for pressure-lubricated bearing motors, and the minimum end play for horizontal sleeve-bearing motors.

• Total motor weight and rotor weight.
• Additional Nameplates: Separate connection diagrams or data nameplates shall be located near the appropriate connection box or indicated location for the following:
• Motors having more than three power leads.
• Space heaters (operating voltage and wattage).
• Temperature detectors (resistance [ohm] or junction type).
• Vibration and position detectors (manufacturer and model).
• Direction of proper rotation (Locate near motor shaft).
• CT Nameplates: When CT's are supplied, stainless steel nameplates shall be provided for each CT and shall be located adjacent to the CT junction box. The information on the nameplate shall include:
• Requirements of ANSI C 57.13 paragraph 6.8
• Location/Orientation
• Polarity
• Ratios (tap ratios)
• Accuracy class
• Winding Temperature Detectors
• Winding temperature detectors shall be supplied with all motors unless indicated otherwise. They shall be three wire resistance temperature detectors, equal to Edison No. T/R-7, 120 ohms at 32°F or 100 ohm at 32°F platinum RTD as specified on the Data Sheet, inserted between top and bottom coil sides in slots where hot spots may be anticipated. There shall be six RTD's, two per phase. Locate detectors at 60 mechanical degree intervals, or group in two's 120 mechanical degrees apart in adjacent slots.
• Leads for the resistance temperature detectors shall be brought out, terminated, and suitably identified on a terminal block. These shall be enclosed in a separate gasketed cast iron terminal box of adequate size to accommodate the necessary wiring.
• Bearing Temperature Detectors
• Provision shall be made for the insertion of temperature detectors in all motor sleeve bearings.
• When specified, three wire resistance temperature detectors, equal to Edison No. T/R-7, 120 ohms at 32°F or 100 ohm at 3 °F platinum RTD as specified on the Data Sheet, with tip-sensitive probes, mounted in NEMA 4 heads, shall be installed, two per bearing. When dial type thermometers are provided then only one dual element RTD (or provisions) as

specified shall be provided. The type of probe detector and its installation shall maintain the integrity of insulated bearings and not compromise the response of the detector.

• Space Heaters: Space heaters shall be provided for preventing condensation during motor shutdown periods. The sheath temperature shall not exceed those allowed for the area classification specified on the Data Sheet. Space heater leads will be brought out to an added separate gasketed cast iron junction box. The space heater voltage shall be specified on the Data Sheet. The surface temperature of the heater elements or the motor enclosure shall not exceed 80% of the ignition temperatures as specified in ANSI/NFPA Standard 70 and 497M.
• Filters
• Dry type air filters constructed of Series 300 stainless steel shall be furnished with Type II weather-protected motors. Filters shall be located at air inlet and shall be accessible for inspection, removal, and cleaning while motor is operating.
• Design filter area so that air velocity does not exceed 600 feet per minute.

• When filters are provided, winding temperature detectors shall also be provided.
• When filters are provided, a differential pressure gauge (Dwyer, Series 2000, Magnehelic) shall be provided. Location of the gauge shall be on the ODE and/or side of the motor enclosure.
• When filters are specified for WP-l enclosures they shall comply with 1, 2, 3 and 4 above.
• Motor Protection
• Motors, 1500 HP and larger, unless specified otherwise, shall require self balancing type differential protection. The motor Manufacturer shall provide three window-type 50/5 current transformers similar to GE Type JBC-0 in the motor terminal box. Secondary connections for the above CT's shall be factory-wired to shorting type terminal blocks in a separate gasketed cast iron accessory terminal box.
• Motors 1500 HP and larger, unless specified otherwise, shall be equipped with surge arrestors and capacitors. They shall be located in the motor leads terminal box. Arrestors shall be metal-oxide station class type.
• Motor Metering: When specified on the Data Sheet, a CT shall be provided on the motor "B" phase to be used by the Owner to meter motor current. The CT shall have a 5 ampere output and a primary turns ratio as specified. Secondary connections for the above CT shall be factory wired to a shorting type block in a separate gasketed cast iron accessory terminal box.
• Ground Connectors
• Provide a grounding plate with a compression lug connector for 2/0 copper cable on the motor base, on the power terminal box side. Furnish a tapped hole with a compression lug connector as above inside cast iron power terminal boxes. In sheet metal motor leads terminal boxes, a 1/4 inch by 1-1/2 inch by 6 inch copper ground bus shall be provided in the bottom front of the terminal box for easy access by the Owner. This ground bus shall be grounded directly to the motor frame via 2/0 AWG copper wire and compression lugs (the terminal box shall not be considered part of the motor frame).
• Provide a low impedance ground path between the surge pack and the motor stator core. This low impedance path may be provided by running a copper 4/0 AWG wire in parallel with the motor leads. This wire shall be as short as practical and shall bond the motor core to the terminal box using compression fittings. Alternatives to this method must be approved by the Owner.
• Bearing Oil Temperature Gauge

Motors with force-feed lubrication per paragraph 5.3.10.6, and when specified on the Data Sheet, shall be supplied with a dial type thermometer at each bearing with its probe tip in close proximity of the babbitt. This must not bypass the bearing insulation system if present.

• Motor Leads Terminal Boxes
• Terminal boxes shall be weatherproof. These boxes shall be made of cast iron, cast steel, sheet, steel, or steel plate, and shall have hubs or threaded openings for rigid conduit. Cast motor terminal boxes shall be diagonally split, gasketed, and rotatable in 90° turns. Boxes made of sheet steel or steel plate shall have a minimum wall thickness of 1/8 inch. Minimum power leads terminal box size shall be 9 inches by 9 inches by 20 inches internal dimensions. As a minimum, terminal boxes shall meet the requirements for NEMA 4 and be suitable for the area classification specified.
• Drain holes shall be provided at the bottom of the terminal box.

• All cast terminal boxes shall be gasketed/watertight cast iron or steel boxes, diagonally split, rotatable in 90° turns and have all conduit openings threaded.
• Terminal boxes shall be oversized to allow for routing of incoming power cables, stress cones, and additional equipment as specified.
• All medium voltage bus work used in the motor terminal box shall be copper with plated joints, fully insulated, and supported with either porcelain or cycloaliphatic epoxy insulators. Bus connection pads for the customers two hole compression lugs on incoming power cables shall be oriented to allow installation without requiring 90° power cable bends.
• Space heaters with thermostat for terminal boxes provided when specified on the Data Sheet.
• If motor terminal leads pass outside the motor enclosure or where they would be exposed directly to inlet air contaminants, running from the stator to the terminal box, they shall be carried in listed RGS conduit (3/4 inch minimum).
• Auxiliary Boxes/Enclosures
• Auxiliary boxes shall be cast steel or iron boxes, gasketed water tight (NEMA 4), diagonally split, rotatable in 90 degree turns and have all conduit openings threaded.
• Auxiliary boxes shall be suitable for its intended function for the area classification specified and the type equipment in the box.
• All conduits to auxiliary boxes and devices shall be listed rigid galvanized steel (RGS) conduit only, minimum size 3/4 inch. When flexible conduit is required it shall be liquid tight listed flexible conduit (e.g. vibration probe conduits).
• See Section 5.3.7 for information on vibration probe equipment enclosures.

TESTING

• General Testing Requirements
• All tests that require energization of the motor shall be done at rated voltage and frequency, unless indicated otherwise in this Practice.
• The motor Manufacturer shall include in the quotation the cost for only the Owner required tests as specified on the Data Sheets and as described in Section 6.0 of EP 13-3-2. Additional Manufacturer standard tests, that are provided at no additional cost, may also be included.
• Routine Test
• Each motor shall be given a routine (commercial) test to demonstrate that it is free from mechanical and electrical defects. This test shall be conducted in accordance with this Practice and applicable portions of IEEE 43, IEEE 112 and NEMA MG 1. This test shall include but not be limited to:
• Manufacturer's standard test.
• Measurement of no-load current (each phase) and speed.
• Measurement of stator winding resistance.
• A high-potential test on stator.
• An insulation resistance test on stator with a 2500 VDC (minimum) megohmmeter (for systems less than 2.4KV, a 1000 VDC (minimum) megohmmeter), and a polarization index test per IEEE 43.
• Measurement of vibration (at no load is acceptable) after motor temperature has stabilized per paragraph 6.2.2

• For motors with both bearings insulated, a bearing insulation test shall be performed per IEEE STD 112- Megger Test Method.
• A determination, by calculation, of locked rotor current.
• Air gap measurements.
• Bearing temperature rise.
• The motor shall be operated for a minimum of 1 hour after the bearing and stator temperatures have stabilized. Stable temperature is defined as no more than a 1°C change in two successive 15-minute intervals.
• The following basic requirements shall be met for all running tests:
• Tests shall be made on the fully assembled motor including contract components and accessories, and prebalanced coupling half (including idling adaptors) if supplied. Terminal boxes may be excluded.
• If applicable, all oil pressures and viscosities shall be at their maximum operating temperature values recommended in the Manufacturer's operating instructions for the specific unit under test. Oil flow rates for bearing housings shall be determined (Acceptable methods other than flow meter may be used). Test stand oil filtration shall be 10 microns or better.
• All warning, protective, and control devices shall be checked and adjustments made as required.
• For critical speed considerations, a test shall be made with coupling half-mass-moment(s) equivalent to that of the contract coupling(s).
• During the running test, the mechanical operation of all equipment being tested and test instrumentation shall be satisfactory. Unfiltered and filtered radial and axial vibration measurements shall not exceed the limits specified in 5.3.6 and shall be recorded throughout the operating speed range.
• When radial vibration readings are taken directly on the bearing caps, they shall be taken in both the x and y planes.
• For a routine test, radial and axial vibration readings shall be recorded at 15-minute intervals for a minimum of one hour after temperature stabilization.
• If replacement or modification of bearings or seals or dismantling to replace or modify other parts is required to correct mechanical or performance deficiencies, the initial test will not be acceptable, and the final specified shop tests shall be run after these replacements or corrections are made. During this run, rated voltage, stator amps, watts, and vibration shall be measured to confirm the correction. When only the seals are replaced then only a no load test is required.
• Facilities to ensure against entrance of oil into the motor shall be in operation throughout the test. Any violation of this condition requires termination of the test until correction is made.
• The Manufacturer shall maintain a complete, detailed log and plots of all final tests and shall submit the required number of copies to the Purchaser, including data for bearing temperatures, rotor balancing, critical speeds, and vibration measurements taken over the operating speed range and the spectrum analysis. A description of the test instrumentation and certified copies of the instrument calibrations shall be available for the Owner's review.

• The Owner shall be permitted to use his monitoring and/or recording equipment in conjunction with the vibration transducers mounted on the machine to record the dynamic behavior of the machine during testing.
• All purchased vibration probes, transducers, oscillator-demodulators, and accelerometers shall be in use during the test. For motors without provisions for non-contacting probes, vibration measurements shall be made using bearing housing mounted velocity transducers. See paragraph 5.3.6.3 for additional requirements.
• Shop test facilities shall include instrumentation with the capability of continuously monitoring and plotting revolutions per minute, peak-to-peak displacement, and phase angle (x-y-y). Presentation and recording (with hard copies for the Owner) of vibration displacement and phase marker shall also be by spectrum analyzer including 10 orders of running speed as a minimum.
• The vibration characteristics determined by the use of the instrumentation specified in 6.2.11 and 6.2.12 shall serve as the basis for acceptance or rejection of the machine.
• Current, voltage and power in all three phases shall be measured and recorded, for all running and locked-rotor tests (where applicable). All required data shall be taken at cold start continuing throughout the test. For heat run test, data shall be taken as a minimum, every 30 minutes during heat-up, and at 15 minute intervals after temperature stabilizes.
• All windings and bearing temperature measurements shall be made using permanently installed detectors, when purchased. For cases where detectors are not supplied the method used must be approved by the Owner.
• Unless specified otherwise, measurements of items in Paragraphs 13 (vibration), 14, and 15 above shall be recorded every 15 minutes.
• For motors with un-insulated bearings, a measurement of end-to-end shaft voltage shall be made with the motor operating at no load and rated voltage. Shaft voltage shall not exceed

0.2 V rms.

• All tests shall be made with the shaft axis in the normal running position. The motor shall be mounted on a "massive foundation" having a natural frequency of at least 25% removed from the motor rotational-speed frequency. NOTE: A "massive foundation" is one whose vibration is limited to 0.02 inch per second velocity (peak, unfiltered) on test (in the vertical, horizontal, and axial planes) above any background vibrations. The motor feet shall be firmly clamped and properly shimmed. A check for soft feet shall be made. When each hold-down bolt is loosened, the respective foot movement shall not exceed 0.001 inch.
• Complete Test
• When specified on the Data Sheet, motors shall be given the complete test listed below in addition to the routine test specified in paragraph 6.2 of this Practice. This test shall also be in accordance with IEEE 112, C50.41 and NEMA MG1. This test shall include:
• Determination of efficiency and power factor at 100 percent, 75 percent and 50 percent of full load. The preferred method of determination is NEMA MG1 - 20.52 and IEEE 112 method B-Dynamometer; the use of IEEE 112 Method F must be approved by the Owner, however, if Method F is proposed by the Manufacturer, the Manufacturer shall provide a detailed explanation of the test procedure including assumed values and specific test data taken per IEEE Std. 112-1991.

• Determination of locked-rotor current and torque shall be made using a three-phase power source. Full voltage testing is preferred, however the locked rotor test can be performed at either 50 or 25 percent of rated voltage.
• Determination of percent slip at full load.
• Determination of full load and breakdown torque.
• A temperature test (heat run) at maximum continuous rated service factor. This test shall include a minimum running time of four hours, with a minimum of two hours at rated temperature after temperature stabilization.
• Vibration tests with the machine at rated temperature at no load or full load (see Paragraph 6.3.5 for no load test method).
• Motors that do not meet or exceed the guaranteed efficiency values as quoted shall not be accepted by the Owner.
• Acceptable temperature test loading methods are as follows:
• Shaft load the motor with a dynamometer.
• Connect two machines back-to-back in a motor generator configuration.
• The dual frequency superposed method per IEEE Standard 112.
• Warming up of the machine by blocking ventilation openings or shutting off the cooling water on water-cooled machines is not acceptable.
• Motors shall have shaft and bearing housing vibration verified with the motor at rated temperature. Vibration acceptance for induction machines can be based on a procedure which allows for quickly disconnecting the motor from a dynamometer, or removal of the superposed frequency source at the end of the dual-frequency test, and recording the no-load vibration with the machine hot.
• The motor shall be considered to have reached temperature stability when the requirements of Paragraph 6.2.2 are met.
• The magnitude of vibration vector changes from no load to rated temperature shall not exceed 50 percent of that specified in Table 2 and Table 3. For motors which do not comply with this vector change allowance while remaining within the specified limits of Table 2 and Table 3, the Manufacturer shall demonstrate the structural stability of the motor. The vibration test shall be repeated by letting the motor cool down and then reheating it to achieve a stable temperature while recording the vibration data. The magnitude of vector change in succeeding vibration amplitudes, for the cold motor under no load and for the hot motor at rated temperature, shall be within 10 percent of the allowable limits shown in Table 3.
• Special Tests

NOTE: These tests are only to be provided when specified on the Data Sheet and authorized in writing by the Owner.

• Surge Test: When specified, surge comparison tests shall be made of turn insulation in the fully wound stator just prior to making up coil-to-coil connections per IEEE 522. The peak voltage shall equal the motor rated voltage.
• Stator Winding Immersion Test: When specified, motor stators equipped with sealed insulation systems shall be tested in accordance with the latest revision of NEMA MG1 - 20.49 by means of a water immersion test.

• Bearing Inspection: Prior to running tests, each bearing's journal-to-bearing clearance and bearing-shell-to-bearing-cap crush and alignment shall be determined and recorded. Anti- friction and bracket-type sleeve-bearing inspection shall include a no-load run observation to ensure bearing operation is without excessive noise, heating, or vibration and a check for lubricant leaks. After all running tests have been completed, the shaft journals and bearings shall be inspected by completely removing both the top and bottom halves of each sleeve bearing. Where accessible, the condition of the lubricant shall be visually examined after the run.

6.5 Witness Test

When witness testing is specified, the Owner shall witness the complete test as specified on the Data Sheets and on Owner approved contract documents.

DRAWINGS AND DATA

The drawings and data required shall show the equipment as ordered and built. Typical drawings are not acceptable, unless revised to show as-built equipment and identify the specific equipment ordered. The Owner's name, job number, P.O. number and item number shall accompany all drawings and data. Data and drawings shall be supplied in the quantities and format specified on the Data Sheet.

• Data to be Supplied with Quotation (refer to Manufacturer document requirements in Requisition for additional requirements).
• Outline drawings for the motor and for all auxiliary equipment not mounted on the motor.
• Guaranteed data for efficiency (at 1/4,1/2, 3/4, and full load), pull-up, and breakdown torques at rated voltage.
• List of all devices used which are not manufactured by the motor Manufacturer. The list shall indicate the type, Manufacturer, and catalogue cut sheets or similar data.
• A priced list of normally recommended spare parts for each type of motor and associated auxiliary equipment quoted.
• All exceptions to this specification.
• The Manufacturer's portion of the Motor Data Sheet completely filled out, including alternate quote for high efficiency design, if offered.
• Calculated start-up curves showing torque and current versus speed, thermal capability curve.
• Guaranteed motor starting for system and load conditions provided on the Data Sheet and/or Driven Equipment Data Sheet. Speed torque and acceleration curves shall be provided.
• For motors supplied with cast aluminum rotors, provide test procedure with acceptance criteria to verify the casting is void/crack free.
• Drawings and Data to be Submitted to the Owner for Approval
• Approval and certified drawings shall show:
• The size, rating and exact location of all conduit connections, together with the location of all piping and instrument connections.
• The size and location of anchor bolt holes.
• The location and arrangement of all user connections.

7.3

7.3.1

7.3.2

7.3.3

7.3.4

7.3.5

7.3.6

• The total weight.
• The foundation loading diagram, the heaviest maintenance weight and name of the part that must be lifted during dismantling, all horizontal and vertical clearance necessary for dismantling purposes and the approximate location of lifting lugs.
• The direction of rotation.
• The marking of terminal leads.

Bearing reference data, consisting of bearing Manufacturer's part numbers, including bearing cartridges, oil rings, and oilers, shall be furnished.

For each auxiliary system supplied (e.g., resistance temperature detectors or space heaters), a certified wiring diagram shall be furnished. The diagrams shall clearly indicate the extent of these auxiliary systems to be furnished by the Purchaser.

Guaranteed Data: Current, torque and power factor at locked rotor. Current, torque, power factor and efficiency at 1/4, 1/2, 3/4, and full load. Power factor, efficiency, pull-up and breakdown torques at rated voltages are to be guaranteed data.

Curves showing torque, current and power factor versus speed at 70, 80, 90, and 100% rated voltage.

Curves showing predicted current versus time for starting motor and load at 70, 80, 90, and 100% voltage.

Transient reactance (X'd) at rated voltage, transient short-circuit time constant (T'd), open- circuit time constant (To), rotor Wk2.

Allowable intervals at locked rotor when motor is cold 40°C ambient) and hot (full-load temperature at 40°C ambient). Provide above intervals at 100% (nameplate) and at 80% volts.

Thermal capability curve (safe time before insulation damage in seconds versus percent rated current to locked rotor current).

Space heater data, number of heaters and total watts.

All data required on the Manufacturer's portion of the Data Sheet and other items requested by the purchase requisition.

Certified Data to be Submitted All items in paragraph 7.2.

Installation, maintenance, and operating manuals (Supply prior to shipment). Spare Parts list.

Material list.

Test data as required in paragraph 6.2 and/or 6.3 and the purchase requisition. For motors with cast aluminum rotors, testing data to verify rotor is void/crack free.

8.0 SPARE PARTS

Within 30 days after approval of drawings, the Manufacturer shall supply a recommended spare parts list with quotation on the basis of the total purchase order. This recommendation shall include spare parts required at start-up and during the first year of operation. Prices shall be valid for a minimum of 60 days after shipment.

SHIPPING

• Each unit shall be suitably prepared for the type and mode of shipment specified. All motors shall be suitably prepared for at least 6 months of outdoor storage from the time of shipment in a manner requiring no disassembly prior to operation (except for bearing and seal inspections).
• The vendor shall provide the Purchaser and Owner with the instructions necessary to preserve the integrity of the storage preparation after the equipment arrives at the job site.
• Preparation for shipment shall be made after all testing and inspection of the equipment has been accomplished and the equipment has been released for shipment by the Owner. The preparation shall include as a minimum:
• Exterior machined surfaces shall be coated with a suitable rust preventive.
• After having been thoroughly cleaned, internal areas of bearings and all auxiliary equipment in oil lubrication systems using carbon steel shall be coated with a suitable oil-soluble rust preventive.
• Flanged openings shall be provided with metal closures at least 3/16-inch thick, with synthetic rubber gaskets. At least four full-diameter bolts shall be used for flanged openings.
• Threaded openings shall be provided with steel caps or solid-shank steel plugs. In no case shall nonmetallic plugs or caps be used.
• The rotor is to be blocked to prevent axial and radial movement.
• Space heater leads shall be accessible without disturbing the shipping package and shall be suitably tagged for easy identification.
• When specified or otherwise required, the normal running bearings shall be removed and shipped in protective crates and the motor shall be equipped with special shipping bearings for shipment by rail or ship.
• Lifting points or lugs, if not obvious, shall be clearly marked. Each motor shall be properly identified with item and serial numbers. All material shipped in separate crates shall be suitably identified with securely affixed, corrosion-resistant metal tags indicating the item and the serial number of the equipment for which it is intended.
• When specified, the fit-up and assembly of machine-mounted piping, coolers, and other equipment shall be completed in the Manufacturer's shop before shipping.
• Exposed shafts and shaft couplings shall be wrapped with waterproof, moldable waxed cloth or vapor phase inhibitor paper. The seams shall be sealed with oil-proof adhesive tape.
• Components (both individual pieces and packaged sets) shipped with mounted pre-assembled piping, tubing, or wiring shall comply with the requirements of the Occupational Safety and Health Administration.

• Auxiliary piping connections furnished on the purchased equipment shall be impression stamped or permanently tagged to agree with the vendor's connection table or general arrangement drawing. Service and connection designations shall be indicated.
• Bearing assemblies shall be fully protected from the entry of moisture and dirt. If vapor phase inhibitor crystals in bags are installed in large cavities to absorb moisture, the bags must be attached in an accessible area for ease of removal. Where applicable, bags shall be installed in wire cages attached to flanged covers, and bag locations shall be indicated by corrosion resistant tags attached with stainless steel wire.
• One of the required copies of the Manufacturer's standard installation instructions shall be packed and shipped with the equipment.

10.0 TABLES

TABLE 1

MOTOR STARTING CAPABILITIES

NOTE:

(1) Where the total load inertia referred to the motor shaft does not exceed 66 percent of the value listed in NEMA MG1-20.42, the number of starts permitted is four.

TABLE 2

BEARING HOUSING VIBRATION LIMITS FOR COMMON OPERATING SPEEDS

NOTES:

• Measured with a velocity sensor or accelerometer integrated to velocity.
• Filtered (± 1 Hz) discrete-frequency velocity at 1X and 2X running-speed frequency and 1X and 2X line frequency, not to exceed 0.08 inch per second, zero-to-peak.

TABLE 3

SHAFT VIBRATION LIMITS RELATIVE TO BEARING HOUSING USING NON-CONTACT VIBRATION PROBES (1)

NOTES:

• The motor is fastened to a massive foundation.
• Vibration displacement at any frequency below running-speed frequency shall not exceed 0.1 mil or 20% of the unfiltered vibration displacement, whichever is greater.
• Vibration displacement at any frequency above running-speed frequency shall not exceed 0.5 mil peak-to-peak.
• Vibration displacement filtered at running-speed frequency shall not exceed 80% of the filtered limit (runnout compensated).

TABLE 4

CERTIFIED INFORMATION REQUIRED IN ELECTRONIC FORMAT FOR INDUCTION MOTORS ABOVE 500 HP PER EP 13-3-2

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