why an induction motor always runs on lagging pf? could it be made to run at leading pf?

Because it is basically a big inductor composed of many windings around a magnetic core. It can't be forced to operate in leading power unless a properly sized capacitor is placed across its terminals.

By the nature of its electrical properties, NO it cannot. It is an induction motor and all asynchronous unit runs at a lagging PF.

If you require it to produce Vars instead of consuming Vars, then you will need a synchronous motor.

Hope that helps.

The nature of induction motor is inductive.....due to this it takes reactive power to produce magnetic field due to this induction motor is lagging pf nature.....

It operates at lagging pf because it is an INDUCTION motor

Dear Mr.Alan Maltz, Do you really think that with "a properly sized capacitor" we can change pf from lagging to leading? how is it possible? Do you have any calculations or documents about it?

I am completely agree with Mr. Lee.

Abishek
The clue lies in the name. Anything inductive draws lagging current. QED

yeah from the name itself... induction motors, inductive load.. -jQ, lagging current...

Of course you can run induction machine at leading power factor. But in that case, it supplies energy instead of absorbing, which means it becomes not the induction motor but the induction generator.

@Mr. Kim.
just by making pf leading an induction motor will not run as induction generator because slip of IM is positive but of induction generator is negative.i just want to know that is it possible to make an IM draw leading pf by using var compensators.