WIRE NUTS, VERSES LUG CONNECTIONS

[dArsonval]

The method, arrangement, practice, protocol, requirement, etc. related to physically connecting
motor leads to a power supply are numerous.

Obviously, an 18,000 HP motor is not going to be electrically connected using wire nuts.
And a 1/20 HP bathroom fan motor is not going to require soldered, lug connections.

When a typical NEMA Frame motor leaves a repair shop, should it have lugs on its leads?
Or, is it more common to leave that decision to the customer?

How do you send your repaired motors back to your customer?
Do you put lugs on the motor leads, or leave them empty?

John

 

[quickee]

Typically, if I send a motor in for repair it will be returned exactly the way I sent it in. If it had lugs, it returns with lugs. If it had bare wire ends, then that's what comes back.
Hope this helps,
Tim

 

[jraef]

In every industrial plant I have worked in or been associated with, wire nuts were contraindicated on anything that will experience vibration, i.e. motors (among other things). But does that mean people don't use them on 1/20HP bathroom fans? No, they do all the time and 99.99% of them are problem free. The sales literature from 3M and the like say they are a good solution for motor connections, but I personally would never use them, I have seen too many fail. I have found Blue wire nuts used to connect a 40HP motor, the vibration against the side walls wore right through the blue plastic and caused an arcing ground fault inside of the peckerhead.

But I don't thing there is a specific rule anywhere that prohibits the practice.


"Will work for salami"

 

[rhatcher]

In my opinion, compression lugs should always be used on NEMA frame motors. However, in my experience, I have seen some facilities that use Kearney split bolt connectors as shown in the link. I have also seen wire nuts used on smaller NEMA motors.

https://www.platt.com/search.aspx?q=kearney+split+bolt

That being said, the best practice is, as stated by quickee, to return the motors to the customer the same way that they were received. If you are not certain, you can always ask the customer if they have a preference.