[Ken_Shea]

OK, Cold weather is almost here and once again my same unfixed issues is cropping up.
The 5hp air compressor motor in cold weather will trip either it's own overload protection or the supply circuit breaker (40 amp) in it's attemps to start up.

What has to be done is repeated attempts to start the motor and manually trip the supply breaker and wait a bit for head pressure to release before it trips on it's own and then wait till it cool to try again. The more attempts the further it goes in to full start rpm before it trips out the one or the other overload protection breakers then it eventually will start and run normally even during it's normal cycle of keeping to adjusted pressure.

Looking for suggestions on what it may be. It has two starter capacitors, maybe one weak or bad? or both?

Thanks
Ken

[ifixcnc]

Caps are easy to check or change, but not sensative to cold. Maybe put a lighter oil in it, or warm it up with a hair dryer.

[Al_The_Man]

Is this a twin piston type? If so look at some different sump oil, you may have a heavy oil in it, you can get compressor oil also that may be more suitable.
Al.

[Ken_Shea]

It's a single piston Al but IFix and you have made a good suggestion, I'll change it to proper oil, seems I had put 30 weight in it when the compressor pump was replaced.

[mactec54]

It's a single piston Al but IFix and you have made a good suggestion, I'll change it to proper oil, seems I had put 30 weight in it when the compressor pump was replaced.

Changing from 30W is not going to help very much, Does the Motor have enough Hp for the Compressor Pump, is your Pressure Switch working correct, this releases the Pressure for an easy start up, if you don't have a Pressure Switch, then this should be added & will most likely solve your problem

[Ken_Shea]

5hp, it is a replacement for the original with same hp, rpm unit though not compressor rated what ever that mean.
I am satisfied the pressure switch is working as required, as mentioned you can hear the head pressure bleed off and there is no real resistance when turning the large pulley at that point.

I may look into a smaller drive pulley, would cause it to pump longer but would increase starting torque.
Getting the original fixed is another option though not wanting to spend the money for that presently.

[Al_The_Man]

I I'll change it to proper oil, seems I had put 30 weight in it when the compressor pump was replaced.

If it only occurs with the onset of cold weather, this does not usually affect Motor rated run capacitors, so I would definitely look at the oil as a possible help, even if it does not happen to cure the problem completely, at least it is a move in the right direction, I have a twin cyl run off of a 2hp motor and put compressor sump oil in it.
It gets down to -40° around here in winter.
Al.

[Ken_Shea]

-40, I don't know how you deal with that, used to frequently hit -20 here in Ohio many decades ago but no so much any more, last year was a colder winter and I believe it hit -17 a few times but not for long, like overnight in low lying areas.
Going to get some 10 weight for the winter and try that.

[xjdubber]

5 HP motor should have FLA of about 20 amps, with cold weather the compressor head will be harder to get spinning. that motor could be drawing about 60 amps at startup and depending on the tripcurve on the the breaker it might be really close at warm weather, never mind cold weather.

[LeeWay]

You can use thinner oils in Winter. I think it needs to be non detergent oil though, so that may limit what you can actually use. Detergent oil can foam up badly. It all has cleaning properties, but detergent type actually has cleaning additives. I think some synthetics are non detergent as well. A little research on the brand choices you have in mind should find out for sure.

[Ken_Shea]

Did find this on the internet so it has to be true "Compressor Rated"
My be the culprit if true.

"Compressor duty" is a marketing term so it can mean anything but probably it means the motor has a NEMA rating of C or D. It is designed with a higher starting torque, maybe a specialized pull-up torque curve, and a heavier start winding. Not something you'd need on a table saw but necessary for something like a compressor or pump that doesn't have some sort of clutch"

[Ken_Shea]

I think it needs to be non detergent oil though, so that may limit what you can actually use. .

It does call for Non-Detergent and it may not be locally available, all you see in the parts stores are 30.
Think I'll call first before burning up gas. You may have saved me a trip and money with your post.

[Ken_Shea]

OK,
As suspected, the only two auto parts in the town and neither carry 10 weight.
Maybe they can order it in for me.

[LeeWay]

Check Lowe's Home Depot and many hardware stores. They usually stock compressor oil.

[Ken_Shea]

Lee,
They do carry a couple brands of compressor oil but no mention if viscosity for the synthetic and it's 30 weight for their petroleum based, the synthetic does say all weather but no way of knowing what that may mean by comparison to 30weigth Non-Det.

May have to order on-line, 10 weight non-det is available.

Just got a call back from O'Rileys, they can order the 10weight it in, can pick it up tomorrow.

I'll reply whether or not it helps, needs changed now anyway.

Ken

[LeeWay]

I live in South Alabama and it rarely gets cold for long here. It will be 32 degrees low this weekend though. My older compressor has had trouble starting it's whole life. It's about 10 years old and is on it's third motor. It is a 60 gallon Husky from HD. Older style twin cylinders.

I bought the newer version of the same unit for the new shop last year.

I always run 30 W in them, but will switch to 10 in the older one and see how it fairs. Right now I think it has a stuck valve or hole in the diaphragm or something. It just free wheels and I haven't had a chance to take the head off yet.

[Ken_Shea]

I know the original Ingersol-Rand motor is substantially heavier then the one used to replace it.
As mentioned, if the oil does not help I'll replace the pulley with one half it's size.
It's not used every day but used a lot when it is, air tire changer (It leaks air pretty bad) , bead blasting, high volume use at those times.
Next summer I'll look into fixing the original, it needs bearings as well but that is not a difficult job if I can find a simple fix for it not starting at all.

Sorry that you have to suffer through the 32º, it's gotta be tough


Ken

[LeeWay]

Sorry that you have to suffer through the 32º, it's gotta be tough


Ken

Go ahead. Rub it in. Maybe that will help me keep warm.

[Ken_Shea]

Was just joshing you really Lee, it's about 35 here now with light rain, not the least bit comfortable outside so 32 ain't no short sleeve weather.

[LeeWay]

I saw the smiley face. I spent many years in Germany and a lot of time in the Northern US. I'm no stranger to it, but I don't care for cold weather.
I do like it cold in my shop, but in the Summer time.

Oddly enough, one of my favorite things to do in Germany was snow skiing. Downhill. Not that cross country stuff.