When i plug in my compressor it wont turn the pump with out help?

by kenneth mileski
(halifax massachusetts)

if i help the motor to go it will turn but otherwise nothing


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Bill says...

Hi Ken.

First check and see what else is on the same electrical circuit that your compressor is on. Make sure that none of those items are pulling power at the same time as your compressor is trying to start.

What helps the motor get going when you turn on the compressor is a start capacitor. This is like a battery for 120 Volts, but rather than trickle it out, it "dumps" it's charge into the circuit very quickly, providing the inrush current that your motor needs to get started, and which the existing circuit cannot supply. Once the motor gets going, there is enough juice in the circuit to keep the motor going.

I think you may have an issue with your start capacitor. I would take the motor off and go to an electric motor rebuild shop, and ask them to test it and the capacitor.

Cheers,

Bill

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Thermal cutout switch?????

by Ace Gardner
(Chatt.,Tn.)

I have a I.R. 5H.P. 80 gal tank and the thermal cutout switch on the motor keeps setting after four or five cycles of the compressor coming on and off.

I can let it cool down for about 30 minutes and it will run another four to five cycles and cut off.

I.R. help line said that the wiring was wrong. Not hard wired into breaker box and has caused damage to capacitors in motor. The compressor has run for three years set up the way it is currently with no problems. Bad Thermal Switch or Capacitors????? Thanks, Ace Gardner lodadeo@hotmail.com

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Bill says...

Impossible to tell. It were me, I'd either replace the thermal switch first, as it will be the cheapest, or I'd remove the motor and take it to an electric motor rebuild shop for testing.

They will be able to tell you if it's the thermal overload switch, the capacitor or the motor.

Cheers,

Bill

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Mar 04, 2012
Similar problems with emglo compressor
by: Adam Stalilonis

I was told the same thing by the help line for emglo, I had my compressor on a dedicated 20 amp circuit when 15 amp was min requirement. I ran my compressor for a couple months when i started having the same problem, had the warranty so they replaced it for me and had the same problem again with the new unit. Interested to learn what the outcome of your problem is.

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Motor won't start with high pressure

by Rocky
(north port FL)

When low pressure in tank unit starts right up. When there is pressure in the tank and it's topping off the pressure, electric motot jumps back and forth like it's trying to run in reverse. I'm guessing a starting capacitor on the motor!

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Bill says...

Rocky, if the motor starts OK at below the low pressure cut in, it should start fine too at normal cut in.

It doesn't sound like a start capacitor problem to me, though I'm not entirely sure what you mean by the motor "jumps back and forth like it's trying to run in reverse".

By all means, take the motor and capacitor to an electric motor rebuild shop to get it checked out.

I'd want to check out the pressure switch too.

Cheers,

Bill

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Compressor motor tries to start and pops a fuse

by James
(Grand Junction, CO)

Plug wiring

Plug wiring

Plug wiring
Safety switch wiring, blown fuse socket is empty
Compressor wiring
The fuse

Kobalt 5 HP 80-Gallon 155 PSI Electric Air Compressor

Compressor:
http://www.lowes.com/pd_48365-1126-TQ3126_0__?productId=3370338&Ntt=air+compressor&Ns=p_product_price|1

Safety switch:
http://www.lowes.com/pd_92606-296-L211N_0__?productId=3365260&Ntt=safety+switch&Ns=p_product_price|1

I bought this brand new a few days ago.

I have 50A service to my garage and hooked the compressor up using a 50A plug I used to use for my welder. Using 10 gauge wire I went from a 50A plug, to a 30A fused safety switch (see above) with 30A type T fuses, then to the compressor.

When I turn it on the motor starts moving and after about a second the fuse blows. So far the same fuse has blown four times in a row.

Some quick facts about the setup:
1) If I take the belt off the motor runs fine.
2) I can turn the pump pulley by hand
3) I have checked all the wires with my meter and I can't find a short anywhere.
4) With the power on I see the correct voltage at the motor
5) I swapped the legs and the same fuse blew again.

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