AC Motor

[Humble2000]

If I run an AC motor without a load, and the voltage drops current drops too.in what situation if the voltage drops ,current goes up. I guess when I have a load on the shaft and motor tries to compensate for that load right?
Please refer me to articles on this subject.

Thanks

 

[dpc]

I think the condensed MG-1 standard (it's free) has an explanation of the impact of variations in voltage and frequency on motor performance.

http://www.nema.org/stds/mg1condensed.cfm

A motor under load will draw more current when voltage goes down. Think of it this way: Power out of the motor needs to stay the same, so when voltage goes down, the current must increase to provide the same amount of output power.

As a first approximation, you can model an ac motor as a constant kVA device for power flow analysis.