Motor Connection

You might not be able to do this. If you know that you have a three phase induction motor, then you can make a reasonable assumption from ohmmeter measurements which wires are for which coil. But if you actually have a synchronous motor, a stepping motor, a DC servo motor or a universal motor then you may not be capable of wiring this motor in a delta configuration.

if u have 6 ends of 3 widings you can identify with the help of multimeter by measuring resistance

The ohmmeter gets you part of the way there, but you also need to determine that the windings are wired in the same direction. (Or more yet, which ones are in series or in parallel with each other in the case of a dual-voltage motor.) I think there are some battery-and-magnet tricks for this, but I don't recall them.

Depends on the number of leads you have coming out. Three leads no problem hook them up and see what the rotation is. six leads (double delta or star delta) the phase of the leads is important and a little hard to figure). 9 leads (dual voltage with some leads terminated in the motor) 12 leads (dual voltage all leads for all windings out--facilitates star delta starting). Some times if it is not a large motor or a critacle appilcation you may just hook it up and "let-er fly" wrong phasing will show.

Unfortunatly it is difficult to determim which "hand"
the winding is wound on which determines the phasing of the winding. ie: CW or CCW.

Hi Ammarkhan,

I have been faced with this problem before with a 3 phase 380vac squirel cage motor where I received the motor back from the winders with just the six wires coming out and I had to fit the terminal block. You can solve the problem in a couple of easy steps.

1. Identify the three seperate windings with the aid of your multi-meter on the ohms range.

2. Once you have identified the windings mark the tails of each winding as follows :- winding 1 - U1 & U2 winding 2 - V1 & V2 winding 3 - W1 & W2

3. Now connect the three windings in series i.e. wire U2 to wire V1 and wire V2 to W1.

4. Connect a single phase supply (220vac) to the windings i.e. Live to wire U1 and Neutral to wire W2.

5. Switch on the single phase power to the windings and with your multi-meter measure the volt drop across the following U1 & U2, V1 & V2, W1 & W2. You will be able to see that two windings have the same volt drop and the third is different. Reverse the connections of the winding with the different reading and re-test. All three windings should now have the same volt drop.

6. Switch off the 220v power and now re-mark the coil ends from the start of the series connection you have made as U1 start & U1 finish, V1 start & V1 finish, W1 start & W1 finish.

7. Now first disconnect the three coils and then connect the windings as follows :-

U1 finish connect to V1 start

V1 finish connect to W1 start

W1 finish connect to U1 start

The windings are now connected in Delta

8. With your multi-meter on ohms check the resistance between each of the three wires marked start (U1 to V1, U1 to W1 & V1 to W1). The resistance read should be equal.

9. You are now ready to run the motor by connecting your three phase supply to U1 start, V1 start & W1 start.

10. Check the current on each of the three supply lines to the motor - they should be equal. If they aren't there is a problem and you need to recheck.

I hope this helps you out of your predicament.

Now that's a cute technique. GA, and welcome to CR4.

I take it that the two like-directional windings induce a different voltage in the "backward" one, as shown in the voltage drop readings.

Why not do what I do, call the manufacturer, seems that they all have techs with a cad screen in front of them.