6 Lead IEC Motor Normaclature

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Saturn_Europa

Saturn_Europa

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Fishing Industry
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Electrician Limited License NC, QMED Electrician
480v, 3 phase, motor. Taps are labeled U1, U2, W1,W2, V1, V2.

Is there an rule of thumb for the lead configuration? I am used to the NEMA 9 lead motors.

L1- 1

L2-2

L3- 3

4-7
5-8
6-9

I can do that in my sleep. But one of my plant mechanics called me at midnight about an IEC 6 lead motor and I had to tell him I didn't know. I googled it and ended up with more questions than answers.

He ended up going to another piece of equipment and just copying the way they wired that one. It's probably right.

He bumped tested the equipment and the mixer blade chopped up the thermal/seal cord. So it didn't really matter! One of the hazards of doing a two person job at midnight in a snow storm by yourself.
 

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Each letter is a winding. In NEMA they go by threes, in IEC they go by letters and they are usually six lead. 1 and 4 are equivalent to U1 and U2, 5 and 2 are V1 and V2, 3 and 6 are W1 and W2.

High voltage L1 T1, L2 T2, L3 T3, join 4,5,6.
In IEC L1 U1, L2 V1, L3 W1, join U2, V2, W2.
 
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Saturn_Europa said:
Why are there two wiring configurations? Multi-voltage motors?
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One is 230 volts delta the other is 400Y.




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ActionDave said:
Nice diagrams. If you substitute 1,4 with U1, U2 and so on it makes the translation from iec to nema easy.
Click to expand...

Thanks :) In the end they are both about the same.


Saturn_Europa said:
Thank you everyone for their posts.


What would happen if the leads are wired incorrectly and in the wrong pairs? Would it cause a short or just cause the motor not to run?
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I'd imagine a lot of current and the motor would get really hot... but thats just a guess. To be honest I can only guess.
 
Saturn_Europa said:
...What would happen if the leads are wired incorrectly and in the wrong pairs? Would it cause a short or just cause the motor not to run?
Click to expand...
Most of the time the motor won't start and either trip the breaker or kick the thermal. It depends on what kind of mistake is made. Make up the leads for low voltage and apply high and smoke happens.

Look at mbrooke's diagrams and you can see what each end of the wingdings look like inside the motor and what would happen if you connected power at any one of those junctions. If motors seem too magical just pretend each pair of letters is the ends of a heating element.
 
Saturn_Europa said:
Thank you everyone for their posts.


What would happen if the leads are wired incorrectly and in the wrong pairs? Would it cause a short or just cause the motor not to run?
Click to expand...

The motor would run making the most god awful grunting noise, draws high current and eventually burns out if you’re not on hand to stop it. Over the years I’ve had two motors returned from rewind with a reversed winding. It’s simple enough to sort out by testing but the easiest method is by trial and error.

BTW we rarely use 240V star connection simply because we don’t use 240V 3Ph. The connections are for star/delta starters, thankfully something I’ve few dealings with.
 
Tony S said:
BTW we rarely use 240V star connection simply because we don’t use 240V 3Ph. The connections are for star/delta starters, thankfully something I’ve few dealings with.
Click to expand...
If you don't use 240-3-50, THAT configuration won't allow star/delta. With a 400 supply, you would require sqrt(3)*400 (690V) winding for the star configuration.
 
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