Motor Connections

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Alwayslearningelec

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Location
NJ
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Estimator
Generally speaking if you have a motor with a disconnect switch the switch can either be loose and mounted by the electrician or come integral to the unit.

If it's a loose disconnect and you bring your circuit to the disconnect( if mount on the equipment) you usually then flex over to the motor.
My question is about the terminations. I assume if could vary depending on the motor. Is it usually just terminating the wires on terminals or lugs on the motors? Would you ever need to provide the lugs? I assume times it's just wires nuts if a small fractional HP motor??? Thanks.
 
ptonsparky said:
Larger motors may require lugs of some sort. You can get crimps suitable for the fine strand used in motors. Large to me is 200-300 HP. Not so for others.
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Yea I didn’t see any of our older motors 100 hp 50 hp motors having wire nuts but connector terminals wrapped or provided with insulation like polaris. Smaller motors all had wire nuts
 
retirede said:
On larger motors, we always used crimp-on lugs with brass hardware.
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I don’t know all the terminology for termination equipment so I call it how I can describe it. Brass and aluminum face plates being non magnetic? are required to be placed between nonmetallic conduits holding isolated phase conductors to equipment to reduce heat from transformer action but I’m not sure why brass hardware would be needed in motor terminations for conduits having all conductors in a single conduit (canceling phase magnetic fields)
 
Alwayslearningelec said:
Generally speaking if you have a motor with a disconnect switch the switch can either be loose and mounted by the electrician or come integral to the unit.

If it's a loose disconnect and you bring your circuit to the disconnect( if mount on the equipment) you usually then flex over to the motor.
My question is about the terminations. I assume if could vary depending on the motor. Is it usually just terminating the wires on terminals or lugs on the motors? Would you ever need to provide the lugs? I assume times it's just wires nuts if a small fractional HP motor??? Thanks.
Click to expand...
On most everything you get anymore, there are some kind of terminals already on the leads going to the armature. Yeah small motors sometimes just need wire nuts. But even most of those I have installed recently have a terminal block in the peckerhead, Usually you really only have to worry about the wires you are installing.

If it's ring terminals on both ends and you use nuts and bolts, I just wrap them with rubber tape and finish off with scotch 88

The way I was taught as a kid had friction tape in the mix of the wrapping, but I never have any. I don't think anyone really uses it much anymore
 
Wirenuts are often used for small motor terminations. IMO the bolt and ring terminal combination is the best way to make the connection to the motor. I often see guys cut off the ring terminals and use some other method like split bolts which creates it own problems.
 
Jpflex said:
I don’t know all the terminology for termination equipment so I call it how I can describe it. Brass and aluminum face plates being non magnetic? are required to be placed between nonmetallic conduits holding isolated phase conductors to equipment to reduce heat from transformer action but I’m not sure why brass hardware would be needed in motor terminations for conduits having all conductors in a single conduit (canceling phase magnetic fields)
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Corrosion resistance.
In this context, “hardware” means the nuts, bolts, washers, etc. used to join the ring terminals crimped on to the motor leads and supply conductors. Not conduit fittings.
 
I believe NFPA 79 had some wording against wire nuts at one time although I can't provide an article or section.
 
I rarely see any kind of terminal on the 9 leads of a typical 3 phase motor. Sometimes I do see smaller 3 phase (under 5 hp) motors of international design that have terminal blocks in the motor junction box.
For me the 9 or 12 lead motor will always be terminated using crimp rings, and screws or bolts with nuts. The is will be insulated with 130C, wrapped sticky side out per the instructions and followed with a few layers of 33+, or if available the insulation will be the reusable RayChem GelCaps
 
Interesting product... I've never used them but have seen them recommended.


 
roger said:
I believe NFPA 79 had some wording against wire nuts at one time although I can't provide an article or section.
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Wire nuts are usually not listed for fine stranded conductors. While there are millions of motors working just fine, it is not technically compliant with the installation instructions.
 
Jolted said:
Wire nuts are usually not listed for fine stranded conductors. While there are millions of motors working just fine, it is not technically compliant with the installation instructions.
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Neither are the standard crimp on connectors that I use.
 
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