NEMA vs IEC Motors

Hey guys,

As my employer expands into international projects and manufacturing, we are trying to source more components internationally. This brings up the issue of NEMA vs IEC motors and gearboxes for our projects.

Those of you in the US, do you use any IEC motors? What are some good brands/models for running on VFDs?

Our standard motor would be something like this Blackmax from Marathon:
https://www.regalbeloit.com/Products/Catalog?model=056H17T5302

Do you guys see a mix of NEMA and IEC stuff out in plants? Trying to get a feel on the "customers" end.

TLDR My work is trying to buy some cheap stuff from china

Baldor Marathon, WEG, and Leeson make IEC motors.

You get what you pay for. Cheap motors from China are cheap for a reason.

Be aware that the term "Inverter Duty" is a marketing term with no enforceable standard for mfrs to answer to, other than their market reputation. Cheap suppliers from China have zero regard for this.

My suggestion is to adopt a written standard for what you need and insist that any motor supplier adheres to that standard and provides documentation to the fact that they meet it. You will find that the cheap Chinese suppliers will struggle with that, or the documentation will be impossible to verify because it will come from their own test standards.

As to IEC vs NEMA, an important aspect of that is SAE or metric dimensions. If you are shipping all over the world, SAE dimensions are difficult for the metric users to deal with and get replacement parts for. People here gripe about metric too, but we are more used to it now. But also understand that IEC motor designs are different from NEMA designs in some other aspects as well. For example there is no "Service Factor" in an IEC motor, they are essentially all 1.0SF. That said, NEMA motor mfrs will tell you that when used with a VFD, all motors become 1.0SF anyway. But understand that is because VFDs cause added heating in motors, so the 1.15SF in a NEMA motor allows for that. Not so with an IEC motor and you are sometimes forced to de-rate a larger motor depending on the application.

Expanding on Jraef's comments a bit:

In general IEC equipment is less robust - it will do what it says (if its from a reputable manufacturer), but may not have the tolerance for abuse that NEMA equipment does. That means a bit more careful engineering is required for applications.

Some Pacific rim equipment is quality, but you need to be very careful with selection. If the price is crazy low, run away.

There is a NEMA standard for inverter duty, MG 1-2011, Part 30. Saying "invereter duty" by itself is meaningless, but if a motor meets that standard you have some assurance of performance.

There are differences in efficiency standards between IEC and NEMA, but I believe the EPACT efficiency requirements apply to any motor sold in the US.

Thanks for the info so far guys.

The specific model they are suggesting is an ABB QABP. China says they can get in 460V/60hz, but I can't seem to find anything online to that effect. I would definitely like to stay away from any custom order parts.

Our specific industry is web converting, if anyone has any recommendations for IEC style motors.

In regards to calculating the motor requirements, 90% of our needs are way under 1HP, so it shouldn't be an issue for most projects.

Gomez_ said:

Thanks for the info so far guys.

The specific model they are suggesting is an ABB QABP. China says they can get in 460V/60hz, but I can't seem to find anything online to that effect. I would definitely like to stay away from any custom order parts.

Our specific industry is web converting, if anyone has any recommendations for IEC style motors.

In regards to calculating the motor requirements, 90% of our needs are way under 1HP, so it shouldn't be an issue for most projects.

Click to expand...

That appears to be a motor designed specifically for the China market, made there as well. It might be difficult to get it outside of China. It has an ABB name on it, but like many things made for China, big companies like ABB must find a Chinese "partner" company to do business there. In this case, it looks like those motors are made by Shanghai Electrics Group, then marketed by ABB in China, but I think it would be a stretch to say it's an "ABB Motor". Shanghai Electric used to (or maybe still does) the same thing with Omron for motors that Omron sells only in China.
http://filedown.dq-fx.com/UserFiles/20120821/20120821161252_26870.pdf

I see no discussion of added voltage spike insulation resistance, bearing grounding / isolation or any other special steps taken to make motors operable from VFDs. Also note that they are specifically stating that these motors are NOT labeled for 460V operation, pointing to a possibility of very poor winding insulation.

Two things on IEC motors. First, as mentioned above there is no extra built in as in NEMA motors. They are always Service Factor 1.0. That means you have to design in the headroom you judge is necessary yourself. Second, insist on NEMA MG 1 Part 31 endorsement for those IEC inverter service motors. It is the only neutral responsible rating I am aware of and can be trusted to give you a reasonably appropriate motor for VFD power whether IEC or NEMA. And, one other incidental item---IEC motors tend to be a bit smaller for any given KW. (Probably why the service factor is 1.0!)

In my experience..... Eurodrive makes the best motors and gearboxes on the market!!!!!

Eurodrive is good stuff. So is ABB/Baldor, in my view.