| Difference of IEC standard and NEMA standard |
| Difference | IEC | NEMA |
| Size standard | Metric system | American market/inch (including terminal box outlet thread holes) |
| Global market share | 70% | 30% |
| Enforce standards | EC60034, 60071 | Nema MG1 |
| Common case | Cast aluminum or cast iron | Cast iron or cast steel |
| Common class of protection | IP44 and above | IP20 and above |
| Common bearing greases | Lithium base grease | Polyurethane base grease |
| Common motor junction box locations | upper | Left or right side |
| Motor seal | Sealing ring (higher) | Common splash ring seal (lower)/ high seal ring |
| Motor drainage | No explicit requirement | A drainage hole or vent hole is commonly required |
| Motor starting current and torque | EC-N/NE/H/HE
IEC-N≈Nema A/B
EC-H≈Nema C | Nema A, B, C, D [Common nema B]
The starting current and starting torque are specified.
As ABCD rises, the current increases and the starting torque increases.
Nema D has no corresponding IEC standard. |
| Frequency | 50HZ | 60HZ |
| wiring | Common 6-post patch panel (star angled) | Common 9-post patch board (Double star connection) |
| Allowable supply voltage deviation | Zone A ±5%, zone B ±10% | Standard ±10% |
| Allow power supply frequency deviation | Zone A ±2%, zone B +3%~ -5% | Frequency ±5% at rated voltage |
| Motor duty system | More detailed definition, S1... S10 | Slightly simpler definition |
| Motor overload capacity | Standard 1.0 | Allow 115% overload for a long time (i.e. : factor 1.15) |
| Energy efficiency test method | IEC60034-2-2 B1
Current EU Access IE3 | EEE 112-2017 B CSA390:10
(R2019) Current North American access equivalent to IE3 |
| Insulation requirements/certifications | Low/common CE | High insulation requirements, special stator /(UL/CSA) |
