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I have a problem to indentify which way to conect the winding. in a star-delta winding motor.

The case is:

The name tag on the motor is missing. All it has on the case is 480v and 4-15A induction motor. It has 6 wires come out.

When I ohmed them out. I can tell there are 3 set of windding of wire inside the motor.( But I dont know which is 1,2,,3,4,5,6,)

The question is

How can I indentify them? so that I can connect the current flow in a right direction.

What is the method or procedure to take to indentyfy the setting?

Thanks in advance you all

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Hi koi6456,


This is my suggestion;


Using a continuity tester (ie ohm meter), identify one winding and label one wire "U1" and the other wire "U2".


Identify the second winding and label one wire "V1" and the other wire "V2".


Identify the third winding and label one wire "W1" and the other wire "W2".


Next, connect wires U2/V2/W2 together to produce a 'star point'.


Now apply 3 phase (presumably 415VAC) via a suitable contactor to the three free motor wires with phase 1 connected to wire U1, phase 2 connected to wire V1 and phase 3 connected to wire W1.


If the result of this work is the motor starting and running smoothly in a clockwise direction when viewed from the shaft end, you've done well and been very lucky!


Chances are, it won't be that easy.


What will more than likely happen is that when power is applied the motor will make a load 'hum' and probably won't rotate at all (damage won't occur as long as you don't apply power for more than a few seconds). This behaviour would indicate a 'reversed winding'.


If this happens, choose any of the three winding (at this stage it doesn't matter which one, just remember it for later), lets use U1/U2 as an example. Reverse the connection, ie connect U1 to the star point and U2 to the contactor.


Apply power again. If the motor now starts and runs smoothly, good, you can move on and change the labels on this winding to suit, ie U2 becomes U1 and vise versa.


HOWEVER, if the motor still hums and doesnt run, SWAP THE U1/U2 CONNECTIONS BACK AGAIN and reverse another winding, say V1/V2. If this makes no difference swap that winding back again and try the third winding...


Eventually (there are three combinations), using this method you will identify the reversed winding and the motor will start and run smoothly.


At this stage the motor may start and run OK but in the wrong direction, ie counter clockwise. If this happens simply change the labels on TWO windings, ie change the U1/U2 winding lables to V1/V2 and the V1/V2 winding labels to U1/U2 (be sure not to reverse a winding again though).


Re-test. If the motor starts and runs smoothly in a clockwise direction when viewed from the shaft end, you're done, you have identified the motor connections!:D


I hope this all makes some sense, please feel free to ask for more info. if required.





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