Effect On Motor

[NCT]

 

What will happen if the start and finish of three phase star /delta winding are not connected properly. What will be its effects on motor performance.Kindly give a clear idea.

[AB2005]

As you know very well that a three phase motor has three windings and six wires come out in its terminal. The connection of these three windings should be in this manner that the direction of the rotating magnetic field, generated by each winding, should be in one direction. That’s why we connect U & Z with phase 1, V & X with phase 2 and W & Y with phase 3 in order to gain a one direction rotating magnetic filed.

Now for example, you inverts the connection of winding #1 and connects X & Z with phase 1, V & U with phase 2 and W & Y with phase 3 (prepare a drawing for a good understating) what happen? The rotating magnetic field of Winding #2 & 3 would be in, for example, clockwise direction and the rotating magnetic field of Winding #1 would be in anticlockwise direction. As a result, magnetic fields would appose each other, motor would draw a high current and the circuit breaker would trip.

 

Hope you will be clear.

 

[jraef]

But that is just one on many possible error scenarios.

 

Is this a rhetorical question or did you already do something wrong and want to know how much damage it may have caused? If so, what did you do?