start capacitor size

dragnuts

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have a Davey 3hp single phase submersible pump but the control box is missing the start capacitor. have been to davey dealers but the model numbers do not match apparently a limited model.Wondering if anyone has any information this model. The model number for the control box is #cp4h07-d, and for the pump motor #m4h07b-d-03.
 
have a Davey 3hp single phase submersible pump but the control box is missing the start capacitor. have been to davey dealers but the model numbers do not match apparently a limited model.Wondering if anyone has any information this model. The model number for the control box is #cp4h07-d, and for the pump motor #m4h07b-d-03.

That Pump Motor may have a centrifugal start winding switch built in, so a start capacitor would not be needed.
 
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If a pump has a control box, it requires a start cap. And no sumersible motor has a centrifugal switch in it, thank god. Not even the 2 wire ones. They have a biac switch and a split phase induction motor with HD start windings.
 
I think DonL said that because he doesn't think it is a submersible pump. I don't think Davey makes a submersible either. Still can't find that they do. All I see is the pond type submersible pumps, no well pumps. Can't find that model number anywhere either. When you Google any of those things, this thread is the only thing that comes up. Are you sure it is a Submersible?
 
The thing about start capacitors is that they need to be close to the Winding to be most affective.

Add a bunch of wire in series with the cap and it decreases it effectiveness. 3HP is a nice Load.

What is the formula for that ?
 
I suppose the formula is how Franklin winds its motors and oversizes its caps. Take a look at the Franklin "AIM" manual for a start on their very particular type of motor.
 
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