air compresser motor question?

[74757685k5]

my compresser will only turn on when it is empty. if it has pressure in it when it starts it will act like it has resistance and blowes the breaker.

I think the motor has like 2 speeds but only second works.

this is a camblehausfield 20gal 5hp

how can I fix this.

THANX

 

[diesel4me]

several things...

If it starts ok when its empty,but wont re-start with some pressure still in the tank,it could be the motor getting weak (worn brushes,armature,etc)...another possibility is it may have a valve on the compressor, or its pressure switch, that releases the "head pressure",so the motor wont be straining against air pressure in the cylinder(s) upon start up..also there is a check valve between the pump itself ,and the tank on most compressors..if that fails to hold pressure from flowing back into the pump it will cause much the same thing...usually you'll hear air leaking back into the compressor pump if either valve is leaking or defective..

Oh yeah,not sure about "speeds",most motors only have one used,even if its wired for more,on air compressors..and if the capacitor on the motor used for getting high torque during starting fails,it wont start under load either..

 

[74757685k5]

how can I test the capacitor. I have both capacitor lookin things off of the motor now

 

[AZ79K5Project]

Here are two ways to test. The link looks like a better way.

You can check a capacitor you suspect of being open by disconnecting it from the circuit and checking it with a capacitor analyzer. You can check a capacitor you suspect of being leaky with an ohmmeter; if it reads less than 500 kilohms, it is more than likely bad. However, capacitor troubles are difficult to find since they may appear intermittently or only under operating voltages. Therefore, the best check for a faulty capacitor is to replace it with one you know to be good. If this restores properoperation, the fault was in the capacitor.

http://www.applianceaid.com/micro4.html