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#1
Start by
abhishek sharma
12-15-2013 09:36 PM

why an induction motor always runs on lagging pf?

why an induction motor always runs on lagging pf? could it be made to run at leading pf?
12-16-2013 12:02 AM
Top #2
Alan Maltz
12-16-2013 12:02 AM
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.
12-16-2013 02:54 AM
Top #3
Raymond Lee
12-16-2013 02:54 AM
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.
12-16-2013 05:14 AM
Top #4
Vishnu Kumar Vishwakarma
12-16-2013 05:14 AM
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.....
12-16-2013 08:07 AM
Top #5
Sudipto Ghosh
12-16-2013 08:07 AM
It operates at lagging pf because it is an INDUCTION motor
12-16-2013 10:48 AM
Top #6
Mostafa Noorelahi Alamdari
12-16-2013 10:48 AM
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?
12-16-2013 01:34 PM
Top #7
Mostafa Noorelahi Alamdari
12-16-2013 01:34 PM
I am completely agree with Mr. Lee.
12-16-2013 04:28 PM
Top #8
James Toal
12-16-2013 04:28 PM
Abishek
The clue lies in the name. Anything inductive draws lagging current. QED
12-16-2013 06:45 PM
Top #9
Lester Philip Lualhati
12-16-2013 06:45 PM
yeah from the name itself... induction motors, inductive load.. -jQ, lagging current...
12-16-2013 08:48 PM
Top #10
Wook Kim
12-16-2013 08:48 PM
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.
12-16-2013 11:27 PM
Top #11
abhishek sharma
12-16-2013 11:27 PM
@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.
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