Electrical Engineering Curriculum
Motors
Module from the Electrical Engineering Curriculum curriculum.
Module 2 - Motors and Motor Control · Learning Objectives · 1. Apply NEMA MG 1 Design B/C/D torque characteristics · 2. Select IEEE 841 severe-duty motor for refinery service · 3. Size VFD for torque, speed range, and harmonic limits (IEEE 519) · 4. Compute full-load amps using NEC Table 430.250 (3-phase) and 430.248 (single) · 5. Apply service factor, temperature rise (Class B/F/H), and enclosure (TEFC, WPII, XP) · NEC Table 430.250 3-Phase Motor FLA (selected)
| HP | 115V | 230V | 460V | 2300V | Notes |
|---|---|---|---|---|---|
| 1/2 | 4.4 | 2.2 | 1.1 | - | Fractional |
| 5 | 28 | 15.2 | 7.6 | - | Small |
| 25 | - | 68 | 34 | - | Typical pump |
| 50 | - | 130 | 65 | - | Mid pump |
| 100 | - | 248 | 124 | - | Large pump |
| 200 | - | 312 | 156 | 33 | LV limit ~300HP |
| 500 | - | - | - | 79 | MV |
| 1000 | - | - | - | 155 | MV |
| Enclosure Type Selection | |||||
| Enclosure | IP Rating | Use | Outdoor? | Notes | NEMA |
| ODP (open drip proof) | IP22 | Indoor clean | No | Cheapest, dust risk | NEMA MG 1 |
| TEFC (totally enclosed fan cooled) | IP55 | Indoor/outdoor general | Yes | Most refinery pumps | Standard |
| WPII (weather protected) | IP24 | Outdoor sheltered | Yes | Large motors | Forced vent |
| XP (explosion proof) | IP66 | Div 1 Class I | Yes | Hazardous area | Certified |
| TENV (totally enclosed no vent) | IP55 | Small, intermittent | Yes | No fan | Smaller |
| Submersible | IP68 | Wet wells | Yes | Sewer/sump | Special |
Source: Electrical_Engineering_Curriculum_v1.xlsx · Sheet: Motors
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