# frustrated, please help



## Kawelo (Jan 31, 2017)

I recently purchased an upright 80 gal Husky single stage compressor with 5 hp AC motor, C801H. I live off grid so I purchased a Champion dual fuel 7000w with 9000w Peak generator to run it. The compressor motor runs off 230V and 22amps so I figured the generator would be able to handle it. I brought them home and hooked everything up. The compressor has a suggested 20 minute break in period at 0psi. Everything ran fine for the 20 minutes. The volt meter on the generator showed 245v. After the break in I shut off the ball valve to build pressure in the tank. The compressor and generator worked fine and auto shut off at 155psi. I then re opened the ball valve to check the pressure switch cut in and when the compressor tried to restart at the cut in pressure the voltage dropped on the generator meter to below 100v. I shut off the compressor switch and bled out all the air from the tank and tried starting the compressor again but it caused the generator to drop voltage again and the compressor would only run at half speed. 
I have a feeling that the compressor motor is drawing too much w at kick in but I'm not sure how much draw it pulls or what size generator unit I will need to run this compressor. Both units are brand new. Please advise.


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## motormonkey (Jul 10, 2016)

It sounds like the generator should be adequate to start and run that compressor, at zero pressure or at full pressure. It also sounds like you understand how to calculate your generator's load. You might try seeing if the generator will power some other piece of equipment with similar load characteristics. That would at least tell you if the problem is with the generator or the load. Based on what that tells you, it's probably time to start talking to the people who sold you the equipment. There's obviously a problem with one of them.


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## grouchy-hermit (Nov 28, 2014)

I wonder if the compressor motor's start or run capacitor got smoked during testing.


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## Kawelo (Jan 31, 2017)

Thank you for your responses. I purchased the generator specifically to run the compressor and don't have any other equipment that run off 230V. I popped the cover on the compressor on/off switch and checked the voltage to both legs with the switch in the off position and was getting 120V at both legs. I'm not sure how to check the run capacitor on the compressor motor. The motor is manufactured by Century Motors.


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## motormonkey (Jul 10, 2016)

"I then re opened the ball valve to check the pressure switch cut in and when the compressor tried to restart at the cut in pressure the voltage dropped on the generator meter to below 100v. "

I wonder if the compressor is trying to start under a head of pressure. Maybe the unloader is not working.


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## davefred99 (Jan 20, 2017)

What is the startup amperage required for that 5hp motor. Is 22 amps the continuous or running amps because most motors can require 2 to 3 times there running amperage to get started which would far exceed your 33 amp max load amperage of your 7000/9000 watt generator. Also where you running off gas or propane because you loos 10% of load on propane (less horsepower). I am no expert but I think 2 to 3 hp is about max motor for that generator rating but I could be wrong.
Dave


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## Kawelo (Jan 31, 2017)

Thank you for your responses. I was thinking on the same lines with you davefred99. I'm thinking the 22 amps is the running amps and at start up the motor is drawing way more than that. The unloader was working as I heard it release head pressure when the compressor hit 155psi cut out. I'm not sure on what the initial amp draw is on start up for that motor and haven't been able to find any information on that. I've used compressors with 3hp motors in the past for spraying cars but they don't put out enough scfm and I'm forced to wait on the compressor to build up. I may need to go to a bigger generator but not sure what size I would need and what the cost would be.


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## Osviur (Sep 7, 2015)

Hi Kawelo,

Before to buy a new generator, you may try to increase the unloader " chamber" capacity, adding an extra tank (1/2 gal or so) connected between the discharge port and the unloader valve. In this arrangement, the pump will take some extra seconds to increase the pressure in the extra tank, allowing the motor to speed up in this time, without practically any load and taking a low amperage. At stop time the tank will be discharged to the atmosphere causing a little extra air loss.... and noise. The tank, of course, must be capable to withstand full compressor pressure.

I hope this help you.

Regards.


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