While operating a AC motor via AC drive, motors of rating > 5 HP are connected in delta while those of rating < 5 HP can be connected in star?

Happy new year to all the members of control.com in advance !

 

I guess I don't understand the question, but what they are working around is the current ratings. A given motor star connected draws less current at a given line voltage than the same motor connected delta. So if you have say a 20 amp drive with enough voltage capability to drive the star, you can run a bigger motor connected star than 20 amps connected delta. HTH, Google is your friend.

Regards
cww

 

Sensorless... I can think of one reason for using a delta, and not a wye, motor connection.

If wye-connected, the motor, like any other 3-phase, 3-wire load, exposes the windings to neutral-displacement, even neutral-inversion? This phenomenon causes the phase-to-ground voltages to become unbalanced, further stressing insulation integrity.

Phil Corso

 

Sensorless... correction to the last sentence in my 31-Dec-11 (2:30pm) post!

It should read, "... phase-to-winding midpoint voltages (Vao, Vbo, and Vco) become... !

Regards, Phil