Air compressor worked fine a day or so ago. Today I go to use it and notice the tank pressure is low. Motor doesn't start when I use air. Checked breaker, its on and not tripped. Reset button on motor has tripped. When I pushed it in the motor tries to start but only rolls over slowly. Motor and compressor both roll over easily under normal pressure on the belt from my hand so nothing is dragging... Is there a way to test the start capacitors mounted on top of the motor? The look normal/no evidence of melting etc... 5 HP 230 V motor. Thanks!
Capacitors
- Thread starter P Dubya
- Start date
56rpm
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Rookie2
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Ohm meter or ohm meter with a continuity range. 1)disconnect power 2) short capacitor with screwdriver 3) remove wire/wires on one capacitor terminal 4)place meter leads on capacitor 5) reverse meter leads 6) if meter deflects or beeps at step (5) it is not open. usually they are open when the motor fails to start.
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Rookie2... Using your method I find that I get a short tone for continuity every time I switch the leads back and forth. Same pattern on both capacitors. so by your method that tells me they are ok is that right?
larry_g... Can you be more specific? CF switch? Start winding?
Thanks!
larry_g... Can you be more specific? CF switch? Start winding?
Thanks!
LS6 Tommy
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machsnell
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They are 20 bucks replace it. In the last 3 weeks I have had 3 different heat pumps acting up and all three were the capacitor.
I learned on the last two and replaced them both for 20 bucks each and saved myself from a nagging wife because they worked.
Sent from my SM-G900V using Tapatalk
I learned on the last two and replaced them both for 20 bucks each and saved myself from a nagging wife because they worked.
Sent from my SM-G900V using Tapatalk
Rookie2
Well-known member
NO, my mistake some capacitors have a resistor soldered across the terminals ,then disregard or unsolder or cut. You will only hear a short beep or continuity one way.
www.surpluscenter.com for fair price on most capacitors , buy two !
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The start circuit of a motor comprises 3 components;
The start cap
The start winding
The start or centrifugal switch (CF).
Any one of the 3 fails and you get your symptom. The cap is the most common but the CF switch may have burned contacts and not be closing or mechanical problems. The start winding may be open or shorted and not giving the phase shift needed to start the motor.
lg
no neat sig line
The start cap
The start winding
The start or centrifugal switch (CF).
Any one of the 3 fails and you get your symptom. The cap is the most common but the CF switch may have burned contacts and not be closing or mechanical problems. The start winding may be open or shorted and not giving the phase shift needed to start the motor.
lg
no neat sig line
nehog
Well-known member
Fixed it for ya...
Tommy
I've been an EE for many, many years, and never seen a capacitor damaged by shorting to discharge. If a capacitor was damaged doing this, then I would say it had already failed.
And to test a capacitor, use a capacitor tester. Simple. I have one I will sell if anyone wants one. (Not a toy, not cheap, not light, not safe if used improperly...)