Compressor belt tension, 2 stage compressor

[hans109h]

I just set up a new to me 80 gallon 2 stage porter cable air compressor. I followed the manual for adjusting the belt alignment and tension, and after doing it a few times things are pretty good but it's a little more chattery than I expected.

When I watch the belt, below the pulleys it is very stable and follows a straight line. When I watch the belt above the pulleys the belt looks "strobed" where I can see that it is moving up and down, probably traveling a total of 1 to 1-1/2 inches. Is this normal or do I need to increase the tension on the belt to try to reduce this vertical belt travel?

As a side note, the manual calls for 1/2" if downward travel when applying 5 lbs of pressure to the belt.

Thanks for your thoughts,

Hans

 

[PoorOwner]

I think I have the same compressor. Haven’t really paid too much attention I just ran it as it came from factory. but the whole cage shakes like crazy. But has not fall apart yet. It’s not due to belt tension but poorly casted flywheel and unbalanced. You can maybe try to balance it by trial and error but to be honest no need to bother.

 

[sberry]

Tighten it a little.

 

[matt_i]

A little vibration in the slack side of the belt is not a problem. The reciprocation of the compressor is inherently jerky because the loads are not the same everywhere on the clock so to speak. A large flywheel helps to dampen this some, if the flywheel has been replaced with a regular sheave along the way it probably will be in danger of overheating plus be more jerky than normal.

If its not slipping on startup and you can run right to the pressure switch cutoff without slipping then you should be good for awhile.

 

[OccupantRJ]

If the unit starts jolting while running, or if the pulleys get hot, then there is likely slippage. A belt too tight can damage bearings. Some units come with jack bolts to tension the belt. This can be both good and bad.

 

[hans109h]

Thanks for all the responses. My thought pattern was leaning towards matt_i's comment regarding a jerkiness due to the difference between the up and down strokes of the piston. There doesn't appear to be slippage affecting the ability of the tool to do it's job.

The flywheel is original, the sheave is on the motor side.

Thanks again,

Hans

 

[Citation]

What kind of condition are the pulley groves in? This is on my mind since I'm dealing with a worn V-belt pulley on my home furnace. You might look to see if the sides of the pulleys are in good shape.

 

[seber]

For me that much motion would be unacceptable. The motor pulley on a compressor should be cast iron. If the alignment is good and tension is right then the most likely problem is an undersized flywheel pulley on the compressor. Not much you can do about it.

 

[hans109h]

The sheave pulley on the motor is brand new of cast iron. The flywheel is smooth, no signs of wear or distortion.