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IEC motor application in NEMA land

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thinker

Electrical
Aug 2, 2001
247
We plan to use VFD with AC motor built in Europe, and carrying reference to Standard IEC 60034 on the motor name plate. Are there any data/materials which could help to prove to end user that there is a close correlation between IEC 60034 and NEMA MG-1, Part 31 with regards to inverter duty motor design? I am thinking of white paper with comparison of both standards.
 
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It is not a close correlation. But IEC60034-31 [or TS 60034-31/2010] contains recommendations about variable speed drives-VSD -in part 5 "Efficiency":
5.3 Additional motor-losses when operated on a frequency converter.
5.9 Matching motors and variable frequency converters
5.13 Variable frequency converter efficiency
5.14 Frequency converter power factor
and part 7 Applications:
7.2 Energy savings by speed control (variable speed drives, VSD)
 
I'd check with NEMA - they must have some comparison data available. Also, large multi-national motor manufacturers could probably supply this information.

Sounds like your end-user expects you to actually comply with his specification?





David Castor
 
thinker
I'm not aware of any documents that refer NEMA to IEC of vice-versa when it comes to inverter ratings. There are numerous papers out there specific to each one so it might pay to look at motor manufacturers who build for both markets. I cannot imagine they would use techniques too differently for both.
However, one of the key variables (no pun intended) will be the type of VFD you use and how you are using it.
The switching frequency, the distance you are away from the motor, the voltage you are connected to, methodology of switching.
Not all VFD's are the same.
"Inverter rated motor" is a rather generalist statement and cannot be used in isolation of the VFD, how it is used and where.
A problem a lot of people fall into is not always long motor cable length but very short cable lengths too. The dv/dt level will be very high due to the high rise time.
The attached document from WEG is an interesting one but fails to highlight the impact of short distance between the VFD and motor.

 
Thanks for your comments, the reference to WEG publication is very interesting.I feel my original posting should have not be focused on inverter duty features only. The drive and motor are fully compatible in all technical terms. The EU drive supplier has become the UL certified facility, and ships to USA drives labeled UL 508C. The motor supplier has only IEC 60034 reference on the name plate, and it is not realistic to have them to re-certify their motors to NEMA standards.So we were looking to something proving that both stanards are correlated (in general terms), and could be accepted in USA as is (with IEC 60034 on the name plate).
 
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