My compressor motor is surging high to low rpm after just a few minutes?
by Screaming small engine powersports
(North waterboro me )
I have an older 60 gal twin cylinder air compressor, i just completely rebuilt the cast iron pump added new oil etc.Brand new motor and when i turn it on it runs good for a few then motor surges high to low rpm it is a single phase 1.5 hp motor same as what came off it.
I have a new pressure switch but it is from tractor supply one of the campbell hausfeld ones do you think that may be the issue? it is rated for same pressure.
I have hooked it up both 110v and 220v and same thing happens both ways.
I have it connected to proper amp breakers etc just cant figure this one out any help would be great
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Not being a motor expert, I’ll throw in a couple of thoughts, and then hope that someone that knows what they are talking about chimes in. 🙂
That the motor pulsation begins after a few minutes of running, and during that few minutes presumably you get some pressure build in the tank, then your motor may be reacting to increasing load.
If you are running the motor on 120 VAC as a norm, and you switched the motor to 220, did run a 220 feed?
That a new motor doesn’t run the same as an older motor of the same HP doesn’t surprise me. Cheaper and cheaper and cheaper seems to be the mantra today, and that philosophy is reflected in the quality of the products being supplied.
It is possible that the capacitor(s) in your new motor are causing a problem, and I would check them. See that page on this site.
I am curious to know if the amperage of the old motor and the new were the same?
Compressor motor will surge up and down?
by Nicholas Bennett
(Milpitas , CA united states)
Compressor drive motor will surge up and down in its speed “Wee yaa” is what it sounds like (Hunting)
CSIR motor jumps up and down over and over!
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Nicholas… not being a motor guy I had to do some research on CSIR motors. Here is what I found, courtesy of: franklin-electric.com
“The control box in a capacitor-start / induction-run (CSIR) system contains a relay and a start capacitor. The start capacitor is connected to the start winding in the motor (the red lead). The motor starts using both windings, but as the motor in the CSIR system comes up to speed, the relay removes the start winding and the start capacitor from the circuit. This happens in about one-third of a second, and the motor then runs on the run winding alone with no capacitor. This is why the current in the red lead
of a CSIR motor will be zero after the motor has started.”
I include this for information for you, for myself, and for other visitors.
From what you post, it is clear that something is affecting the motor running.
That something could be as simple as a change in supply to the compressor. Please confirm that you are plugging the compressor right into an outlet that isn’t being depleted by other items pulling power at the same time the compressor is running.
That there is load differential in the pump, against which the motor is running and changing speed, could be the cause. Let’s eliminate that if we can.
You don’t indicate if there are any changes in the pump, or if the compressor is even pumping air. Regardless, with the compressor off, dump all the air from the tank, remove the intake filter (this eliminates a plugged filter as the source of the motor problem), and disconnect the line from the top of the pump head that runs to the tank.
Plug the compressor back in and start it. What happens?
Post more info as a comment here, please.
