Motor Capacitor
Motor Capacitor
(OP)
I must have been asleep in my EE class, but could someone enlighten me on the purpose of a capacitor used with an electric motor? Is it to store energy in order to "jump start" the motor?
I'm looking at a cheap 115vac electric motor for a simple application and it says a 4 uF 370 VAC capacitor is required. How important is it to get a capacitor with exactly these specs? Will the motor run without this capacitor?
I'm looking at a cheap 115vac electric motor for a simple application and it says a 4 uF 370 VAC capacitor is required. How important is it to get a capacitor with exactly these specs? Will the motor run without this capacitor?





RE: Motor Capacitor
RE: Motor Capacitor
But before it gets started spinning, it developes no net torque (the forward torque is equal/opposite the backward torque). So it cannot start itself.
To overcome this, single phase motors need some kind of auxiliary winding with a time phase shift introduced. One of the means for doing this is putting a cap in series with that aux winding.
Without the cap, the motor will run but not start (you have to help it get started, which may not be a safe thing to do). I would think 10% or 20% variation in the starting capacitor value will not be a big deal in most cases.
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RE: Motor Capacitor
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RE: Motor Capacitor
RE: Motor Capacitor
RE: Motor Capacitor
In the UK, they are called "starting capacitors" so I guess electricpete is correct.
No lawsuits please!
Cheers
Harry
RE: Motor Capacitor