# Identifying the windings in a six lead motor



## dronai (Apr 11, 2011)

A good trick I found on another forum. Thought I would share



Can anyone explain how you would go about identifying the windings of a three-phase single speed, 6 lead AC induction motor?
It can be worked out which pairs of leads are the windings with an ohmic check but how do you find the correct orientation of each winding?

I once heard it can be done with a battery and galvanometer... but how? 
__________________


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## dronai (Apr 11, 2011)

Best answer



This is how you do it....

Step 1. Identify the 3 pairs of windings. This is easy, using a multimeter. Mark the ends A,A, for the first pair, then B,B, then C,C etc.

Step 2. Obtain a LOW voltage A.C supply. Around 10 volts will be sufficient. {Note that this will only work with an A.C. supply, not D.C.}. Connect this supply to the wire A,A. but do not turn on yet.

Step 3. Pick *one* end of the pair B,B, and connect it to *one* end of the pair C,C. With the remaining wires (one B and one C) connect to a multimeter set to volts AC.

Step 4. Turn on the supply. Check for a voltage reading on the multimeter. Now please note the following carefully...

The motor windings are referred to as "Starts" and "Finishes". If the connection between B and C is a "Start" joined to a "Finish", you will read a small voltage on the multimeter. 
If no voltage is present, then the connection between B and C is a "Start" joined to a "Start". 
If no voltage is detected, swap one of the wires at the connection between B and C.

Step 5. Lets say you have successfully produced a voltage..Should be around 4 volts..Where did this come from?? {I dont want to sound like a smart a$$, but this is important} If you get to the stage whereby a voltage is produced, then mark the B wire at the junction with C as B1. Mark the C wire at the multimeter as C1. This will give you the relationship between the B and C wires.

Step 6. The above procedure needs to be repeated for the A,A wires....

{Step 6a. Post back here if you are unsure of the steps outlined above}

Step 7. Join the wires A1, B1 and C1 to make a STAR (in Oz) or WYE (in USA) connection. Apply your 3 phase power to test your motor...Get ready to turn it off quick if something goes wrong!!

Good luck


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## dronai (Apr 11, 2011)

The follow up from the OP

IAN

That is perfect! It works... great. It's my new quiz for the workshop guys.

Many thanks


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