Motor Terminals - Start and End Points

Look closely at the wires to see if they have numbers imprinted onto them, which would then conform to a standard diagram. Or are they perhaps colored?

I suspect there may be a way to connect a DC battery to each set of windings and use a magnet to check that all field directions are the same. Or you might be able see where each wire enters the stator, and connect them symetrically.

If it is a small motor, and it is a one speed motor, I think the easiest way is trail and error.

If you look at the possibilities, there are only 4 ways of connection.

• 1ste possibility ........L1=U1.......L2=V1.......L3=W1........and........starpoint= U2=V2=W2..........good way
• 2de possibility .........L1=U1.......L2=V2.......L3=W1........and........starpoint= U2=V1=W2..........wrong way
• 3de possibility .........L1=U1.......L2=V1.......L3=W2........and........starpoint= U2=V2=W1..........wrong way
• 4de possibility .........L1=U1.......L2=V2.......L3=W2........and........starpoint= U2=V1=W1..........wrong way

If the motor is running no load and the test takes only a small time, the motor will not be burned in this short time.

tanx a lot for ur brife ans. have u ever go through this trick.........?

First, it's not a trick and second it is the ONLY SAFE way to identify and phase the 3 windings of a 3 phase motor without risk of electrocution or damage to the motor, and Yes unfortunately I have had to do this many times.

You are very welcome to the answer.

Dear friend,

i told you one of the simple way to find the polarity of the winding, first see the continudty and mark like U1,U2;V1,V2;W1,W2. and connect U2&V1 give 230V AC between U1 and V2 and mesure the voltage between W1 and W2. if we assumed polarity is correct due to transformer action the voltage will induce if not correct the voltage will not come.

Sirs,

I have also learned from the answers, but I believe the assumption has been made that the motor is star (wye) connected. It may be a 6-lead motor with windings suitable for delta connection, depending on the input voltage. Since the star connection places a lower voltage across the windings, it is the correct one to use when first applying power to the motor. However, I believe that possibility of a delta connection should be remembered.

--John M.