i am working in pumping station in which pumps are running round the clock.the rating of induction motor is525KW.we are connected them 300kvar capacitor to improve system power factor to unity (current system pf is .0996) but now motors are running on leading p.f.tell me effect of leading p.f& if by chance motor will run on no load then what will happpen?
2006-07-30 20:46:20 · 2 answers · asked by manggessh p mane 1 in Science & Mathematics ➔ Engineering
It's impossible for an induction motor to run at a leading pf unless it's a synchronous induction motor (where you put a dc supply onto the rotor to 'lock' the rotor to the rotating field). By nature an induction motor runs at a lagging pf because its an inductor, only something capacitive can improve that. You can run a sync ind motor at a leading pf by altering the excitation. I don't think the motor coming off load would make much difference.
2006-07-30 21:12:14 · answer #1 · answered by Anonymous · 0⤊ 0⤋
By adding more capacitors to the cap bank will raise the PF to a leading PF (ie looking from the point of common coupling into the load). However, the voltage will rise and the added capacitance may cause ferro resonence in the transformer/cables etc. It is dangerous to let the PF get into lead.
The overall PF will rise substantially on NL and the terminal volts on the motors rise as well. This may also cause flash overs between phase windings and/or earth faultsl
Souce: Electrical engineer with 40 years experience
2006-07-31 08:41:43 · answer #2 · answered by Bazza66 3 · 0⤊ 0⤋