Parallel Motors Power Factor

[kduff70]

I came across a problem in complex imaginary problem dealing with induction motor and synchronous motors.

the problem states: A 3 phase motor bank consists of 4 motors : 2 of them are induction motors and the other 2 are synchronous motors. The synchronous motors are running in an overexcited state, while the induction motor operate with their usual lagging power factors. Compared to a situation where all motors running with a lagging power factor , what does this indicate for the overall system?

the choices are:

The overall system efficiency is increased

The overall system efficiency is decreased

The transmission supply line losses are increased

The transmission supply lie current are increased

Can some tell me what study material can help me get a good understanding of parallel motor and power factor?

 

[Flyer_PE]

This is just a power factor correction question. The only thing you have to know is that an overexcited synchronous motor will have a leading power factor. The synchronous motors will adjust the power factor for the entire system to a value closer to unity than would be present with all induction motors.

 

[kduff70]

I got it thank you very much for you response

 

[KatyLied P.E.]

If you are still looking for resources GA Tech does a good job of explaining it. I don't know how many CI tests you have but if you can work and understand all PF problems in all 4 books you will have a good handle on those types of problems.

 

[kduff70]

thank you Marcus