Compressor belt bouncing

[sparky7]

Yeah my compressor belt is bouncing quite a bit on the bottom but doesnt slip at all or squeal, tension seems pretty good to me but what do i know.

Should i tighten it up a bit or is that pretty normal?

 

[Zeke]

Flat or v-belt? You don't need to tighten a belt beyond what it takes to not slip, but it shouldn't be flopping around. V-belts should move up and down about 3/4" using your hand and firm pressure. I think flat belts are pretty much the same. You could use your car as a general guide.

Over tightening reduces bearing wear as well as wearing out the belt.

 

[Cougar]

What kind of shape is it in. Does it have a chunk out of it.
Are the pulleys lined up.

Zeke: Did you mean to say, over tightening increases bearing wear?

 

[sparky7]

yeah i think he said it backwards.

Well its a year old quincy qt-54, i aligned the motor and pump/tensioned the belt myself when i bought it. It seems to be bouncing a little bit more now than it was a year ago. The manual says you have to apply a measured 2 lbs of pressure and have about a half inch of deflection.

I will try to find a tension meter tomorrow (cheap) and re tension it, i dont want to over do it, this thing was a major expense to me

 

[Panel Dan]

Hi Sparky,

Overtensioned belts increase bearing wear. This is correct.

What is the measurement of the belt? There should be markings printed with a letter (or letters) indicating the size of the V, and numbers indicating the length in either inches or millimetres.

Also, you say it's not slipping: Are you sure it's not slipping or is it just not squealing?

I normally tension industrial belts using the rule that you should be able to twist it 90 degrees with two fingers, but no more. 2lb x 1/2" deflection is not a huge amount, but an easy check is to twist the belt (WITH THE MACHINE UNPLUGGED). If it can twist considerably more than 90 degrees then it's too loose.

Also, depending on the wear on the V angle of the belt and the distance between the pulleys a bit of bounce may be normal. Check to see that the pulleys aren't worn too. I've seen hundreds of compressors that have had belts wear into the pulleys and instead of having straight V edges, they have rounded edges which means the belt is running on the root and not on the drive sides of the belt.

Take a few pictures and PM me if you need info. I've been in compressor field service for about 8 years and recips are generally pretty easy to sort out.

Cheers!

Danny

 

[socapots]

Will a new belt stretch a bit after some run time?

 

[Ray Kelly]

Will a new belt stretch a bit after some run time?

Yes!! And sometimes they just bounce. If it doesn't squeal, I wouldn't worry about it.

 

[rjpete]

There are two tension specs for belts. New installation and retensioning. The new spec takes into account the expected stretch that will occur.

So, Yes, a belt does stretch from new. They wear as use continues and will still become loose. Typical PM's should include belt tension adjustment.

 

[Panel Dan]

There are two tension specs for belts. New installation and retensioning. The new spec takes into account the expected stretch that will occur.

So, Yes, a belt does stretch from new. They wear as use continues and will still become loose. Typical PM's should include belt tension adjustment.

It will deflect less for the same tension rating once it has stretched out a little bit too.

 

[nehog]

Will a new belt stretch a bit after some run time?

No, belts don't stretch. What happens is that there is initial wear on the faces which looks like stretch. The cords in the belt keeps it from actually stretching.

 

[Zeke]

What kind of shape is it in. Does it have a chunk out of it.
Are the pulleys lined up.

Zeke: Did you mean to say, over tightening increases bearing wear?

yeah i think he said it backwards.

Well its a year old quincy qt-54, i aligned the motor and pump/tensioned the belt myself when i bought it. It seems to be bouncing a little bit more now than it was a year ago. The manual says you have to apply a measured 2 lbs of pressure and have about a half inch of deflection.

I will try to find a tension meter tomorrow (cheap) and re tension it, i dont want to over do it, this thing was a major expense to me

I said it backwards.