Looking for standard for LV electric motors specification

[Shahzad]

Hello everyone,

I am working on creating a specs document for low voltage electric motors as per NEMA, NFPA, CEC and IEEE and IEC guidelines. Does anyone know which standard I can refer to? Also, is there already a developed standard for low voltage motor specs? If so please let me know.

Such as I know IEEE 841 is typically referred. But is there any other document which I can refer to?

Thanks
Naveed

 

[tom baker]

Check to see if NEIS by NECA has a document. I would look at what NEMA has

 

[David Castor]

Talk with your favorite (or least disliked) motor manufacturer/distributor. They generally have guide specs that can serve as a starting point. You just have to edit out proprietary features.

 

[tjkusa]

Are the motors on VFD, are they in a hazardous location, wet location? Need to define application more. General thoughts to consider are ‘Class F insulation with Design B Rise’ to get some contingency built in to your motor, TEFC, and motor winding temp switch - klixon normally closed thermostats that open on high temp which can be embedded in the motor windings and wired in to the controller pilot circuit for shutdown on (or a little before) overload (nice option as it does not require use of special PTC relays complicating the circuiting). See if you can get a copy of NEMA MG1 from Scribd or other and do read over Parts 30 and 31 among others.
All that said, the motors spec should be Div 15 by mechanical or process engineer. EEs just give input. Us EEs are not great at bhp calcs, moment of inertia, ‘non overloading over the entire range’ topics.

 

[paulengr]

Hello everyone,

I am working on creating a specs document for low voltage electric motors as per NEMA, NFPA, CEC and IEEE and IEC guidelines. Does anyone know which standard I can refer to? Also, is there already a developed standard for low voltage motor specs? If so please let me know.

Such as I know IEEE 841 is typically referred. But is there any other document which I can refer to?

Thanks
Naveed

Ok so this is fairly clueless. You must be an armchair engineer, the worst kind.

IEEE 841 was written by a bunch of engineers sitting around pipe dreaming what a “severe duty” motor should be since there is no spec, by reading what others wrote without any motor designers in the room. So garbage in, garbage out. They got it severely wrong by also including a bunch of energy efficient garbage that causes 841 motors in severe duty applications to overheat. This is definitely not a standard motor spec and not recommended. If you want some 841 motors I can make you a deal…

NEMA and IEC have specific generic motor and generator standards. For instance NEMA MG-1 has been the standard for North America for motors for decades. IEC has a competing and similar standard used in Europe but there are many subtle differences. There are motors made to meet both specifications but you need to pick one. DO NOT mix. It will cause conflicts because the way the specs are defined is different.

CEC has standards for the motor controller, not the motor itself. NFPA contains NEC. Again very similar to CEC and they are the same except where they are different. Including both makes a spec with internal conflicts.

IEEE contains a lot of testing specs such as how to test insulation resistance and a very generic motor spec for specialty motors that are so generic they are useless.