Subject: [Shop-talk] Air compressor took a dump.

From: Dave Cavanaugh <[email-masked]>
Date: Sun, 27 Mar 2016 19:27:50 -0700

This afternoon my air compressor locked up.  It's a two cylinder 60 
gallon Campbell-Hausfield that I bought at HD about ten or twelve years 
ago.  5 HP single phase, two cylinder, about 16 CFM at 90 PSI.  The 
first time I heard the belt squealing so I flipped the breaker and got 
the flywheel turning using a pipe wrench.  After a couple of rotations 
it seemed pretty free so I blew it down and it started ok, but when it 
came up to pressure and stopped the flywheel stopped dead; it didn't 
coast to a stop, and when I tried to start it again it was locked up again.

It's not making any more noise that usual, it's just freezing up.  I 
suspect something is getting hot and dragging.  I guess I'll pull the 
pump in the next week or so and tear it down, but I'm tempted to just 
order a new pump and call it good.  This is crappy timing because I'm in 
the middle of a furniture commission and my little portable hot dog 
compressor won't run my Dynabrades, plus I'm moving in about a year and 
building a new shop, which will have a new 7.5 HP, two stage compressor.

Yes, there is oil in the sight glass; in fact I just changed the oil a 
couple of months ago.  I used some 20 Wt ND I had on hand; probably 
should have used Mobil One....but what color cap?

Advice, opinions, suggestions?
thanks
Dave
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From: [email-masked]
Date: Mon, 28 Mar 2016 15:35:52 -0400 (EDT)

> This afternoon my air compressor locked up.  

I assume it has some sort of compression release so the pump/motor does not have to start against high pressure. Make sure that item is working. If it'll start/run with the tank empty but not when full then that might be the issue. 

Eric Russell
Mebane, NC

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From: "Randall" <[email-masked]>
Date: Mon, 28 Mar 2016 13:00:32 -0700

> If you blow it down does it turn freely? If so it sounds like 
> the pressure relief is not working. 

I think Pat is talking about the unloader valve that typically vents the line between the compressor and the tank when the
compressor is not running; so the compressor does not have to push against full tank pressure while the motor is getting started.
Makes sense to me.  Easy test might be to disconnect the outlet at the compressor head and see if it turns then.

Randall

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