Difference between NEMA and IEC standard of three-phase induction motor- Victory Machinery Technology Co., Ltd.

Since 1926, the National Electrical Manufacturers Association (NEMA) has set the standard for motors used in North America. NEMA regularly updates and releases MG 1, a book that helps users correctly select and apply motors and generators. It contains practical information on performance, efficiency, safety, testing, manufacturing, and manufacturing alternating current (AC) and direct current (DC) motors and generators. The International Electrotechnical Commission (IEC) sets the standards for electric motors for the rest of the world. Similar to NEMA, IEC publishes standard 60034-1, the Motor Guide for the global market.

Do you know the difference between the NEMA standard and the IEC standard except for the metric English system? China's motor standard uses IEC(European standard), and NEMA MG1 is an American standard. Fundamentally, the two are basically the same. But it's also a little different in some ways. The NEMA standard and the IEC standard differ from the rotor temperature rise in terms of the power usage factor of the motor. The power usage factor of NEMA motor is 1.15, and the IEC(China) power factor is 1. The other parameters are marked differently, but the substance is basically the same. Let's take a look:

NEMA Motor

IEC Motor

Firstly, the appearance of the metric motor is more beautiful, in line with the Eastern aesthetic, but the British motor pattern is more variety.

Secondly, different comparison

On the whole, it is mainly due to the large difference in mechanical size installation, and IEC is more stringent for sealing; Electrical Nema electrical requirements have a long-term overload factor of 1.15 and UL's common high insulation requirements

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)