Problem with 3HP Craftsman Compressor ~ motor stalls and the breaker pops off
3hp craftsman.It runs from 0 psi with no problem & it goes off at 120 psi.Once I get down to 80 the motor stalls and the breaker pops off.The motor checked out ok,the reeds are working and the unit has oil..Any ideas?
Usually when a compressor reaches it's high pressure setting, the compressor stops.
When compressed air is used, the pressure of the air in the tank drops.
As the application runs, the pressure in the tank drops further and further (sometimes this only takes a few seconds if you are using a high demand air tool)until the pressure in the tank reaches the low pressure set point.
That pressure switch then closes, electricity flows to the compressor motor, and the cycle repeats.
From your description of your problem, I wasn't able to tell if the "motor stalling" occurred when the compressor tries to start, or after the pressure has moved up from the low pressure set point to 80 PSI. I expect it's the former, and it's my guess that you've got a problem with your pressure switch going to ground when it tries to switch the power on.
919.165230 blows fuses
This model is a 25 gallon upright take with what is said to be a 5.5 horsepower motor. I think this is grossly overrated on horsepower though.
The problem is as follows. When you turn the power on the motor turns very slow for about a second or 2 and then pops the breaker in the breaker panel.
I took the thing apart and the pump and motor were spinning freely. I then took the end off of the motor where it has what looks like a capacitor and a coil. There is a switch that is pressed by a clutch like system inside that cover. I manually held it and tried powering the system on repeatedly. Finally the motor just started up and ran at a very high rate. I left it running without a hose on the tank and it kept running for several minutes with no problem. I did release the switch inside the cover once it started also.
I then powered the compressor off and then tried powering it on again. It started up with me assisting the switch one time and then the next several times I tried to repeat this it ran slow and popped the breaker. I put the end cover back on and managed to get it to start without popping the breaker about 1-10 times now, which to me means the clutch system is pressing the switch that activates the start-up circuit.
Do you have any ideas that I can try on this unit?
Can you explain if the second thing inside that end cap on the electric motor is a coil or a capacitor? It says capacitor but it has more than 2 leads which is not how any capacitor I have seen looks.
Tom, this is beyond my simple skills. I'm hoping that a kindly reader will have a look, and comment with some sort of response.
Oh, and make sure the unloader valve is dumping, OK?