The reason for the start cap is to create a close as possible 90° phase shift (L - C) in the start winding, if just a start winding, I doubt it is close to 90° but probably enough to get the initial spin & direction.. Sure a start capacitor increases starting torque, but may increase initial amp draw, makes sense as the cap needs to charge up, so maybe just making a bigger electrical hole to dump current into.
Do you think adding any value of start capacitor would lower current inrush?The reason for the start cap is to create a close as possible 90° phase shift (L - C) in the start winding, if just a start winding, I doubt it is close to 90° but probably enough to get the initial spin & direction.
Pump maker left it off to save money, as it is not really needed, but it was not optimal for every situation, like running off an inverter, I mean who does that, hah! Me.The reason is the sooner it comes up to speed, the lower the current, so the closer the phase shift angle in the start winding is to 90° the more efficient the start cycle/period.
The LC combination of the start winding and the cap value provides this phase angle difference.
|Thread starter||Similar threads||Forum||Replies||Date|
|Limiting capacitor-start motor inrush||Power Electronics||10|
|B||Substitute motor start capacitor?||General Electronics Chat||8|
|G||Start Capacitor values||General Electronics Chat||5|
|Start Capacitor Value for Compressor Motor||General Electronics Chat||9|
|Help please. I have a 240 volt AC induction motor with a start capacitor that gets very hot when running?||General Electronics Chat||2|
by Jake Hertz
by Jake Hertz