Air Compressor Problem - Motor Stalls
in [Repair]
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From: Sparks Fergusson on 4 Mar 2010 00:13 I'm having a problem with my 20 gallon, single stage electric air compressor. It's acting like the motor is underpowered - it pumps up to about 95 psi ok, but then the motor stalls. The unloader bleeds the pressure off, the motor restarts, runs for a couple of seconds, and then stops again...repeat...repeat... It worked fine for years (The pressure switch would shut it down at about 120 psi) but over the past few months, it's gotten worse and worse, and now will only make about 90-95 psi before the motor stalls. I cleaned and lubricated the compressor itself, and it spins freely and doesn't appear to be binding or otherwise have excessive friction. The check valve/unloader is working and the piping is all open and clear. It seems like the electric motor (1/3 hp) just no longer has the oomph it used to. It starts up fine, no humming, no smoking, no bad smells, no clunks. It just doesn't seem to have enough running torque to handle the load like it did before. Anyone have any ideas? Thanks!
From: TonyS on 4 Mar 2010 01:52 [] > It seems like the electric motor (1/3 hp) just no longer has the oomph > it used to. It starts up fine, no humming, no smoking, no bad smells, > no clunks. It just doesn't seem to have enough running torque to > handle the load like it did before. > > Anyone have any ideas? > > Thanks! If it's a DC motor, maybe it needs new brushes?
From: Sansui Samari on 4 Mar 2010 03:37 On Mar 3, 9:13 pm, hates...(a)invalid.invalid (Sparks Fergusson) wrote: > I'm having a problem with my 20 gallon, single stage electric air > compressor. It's acting like the motor is underpowered - it pumps up > to about 95 psi ok, but then the motor stalls. The unloader bleeds the > pressure off, the motor restarts, runs for a couple of seconds, and > then stops again...repeat...repeat... > > It worked fine for years (The pressure switch would shut it down at > about 120 psi) but over the past few months, it's gotten worse and > worse, and now will only make about 90-95 psi before the motor stalls. > > I cleaned and lubricated the compressor itself, and it spins freely > and doesn't appear to be binding or otherwise have excessive friction. > The check valve/unloader is working and the piping is all open and > clear. > > It seems like the electric motor (1/3 hp) just no longer has the oomph > it used to. It starts up fine, no humming, no smoking, no bad smells, > no clunks. It just doesn't seem to have enough running torque to > handle the load like it did before. > > Anyone have any ideas? > > Thanks! I agree to check the brushes, if it's not a brushless motor. Does the unloader bleed the entire tank off? If so, then the check valve is probably bad. It could also be that your shutoff set point has self adjusted back. Say your fill point is at 95 lbs, and your shutoff self adjusts down to around 95 lbs, it can cause it to continuously turn on and off. I had a compressor that used to do this to me for a while, until I put a little locktight on the adjustment screw. It could be just a worn out pressure switch as well. Maybe the spring has become weak in it.
From: PeterD on 4 Mar 2010 08:29 On Thu, 04 Mar 2010 05:13:31 GMT, hatespam(a)invalid.invalid (Sparks Fergusson) wrote: > >I'm having a problem with my 20 gallon, single stage electric air >compressor. It's acting like the motor is underpowered - it pumps up >to about 95 psi ok, but then the motor stalls. The unloader bleeds the >pressure off, the motor restarts, runs for a couple of seconds, and >then stops again...repeat...repeat... Bad pressure switch. The unloader is part of the pressure switch so if it is being activated, the pressure switch is 'saying' that the pressure is sufficient. Maybe it is just mis-adjusted. > >It worked fine for years (The pressure switch would shut it down at >about 120 psi) but over the past few months, it's gotten worse and >worse, and now will only make about 90-95 psi before the motor stalls. Check the adjusting screws, and reset the cutoff back to 120 PSI. Confirm the cuton is at 95 PSI. >...
From: GregS on 4 Mar 2010 10:03
In article <4b8f3f2a.47238118(a)news.eternal-september.org>, hatespam(a)invalid.invalid (Sparks Fergusson) wrote: > >I'm having a problem with my 20 gallon, single stage electric air >compressor. It's acting like the motor is underpowered - it pumps up >to about 95 psi ok, but then the motor stalls. The unloader bleeds the >pressure off, the motor restarts, runs for a couple of seconds, and >then stops again...repeat...repeat... > >It worked fine for years (The pressure switch would shut it down at >about 120 psi) but over the past few months, it's gotten worse and >worse, and now will only make about 90-95 psi before the motor stalls. > >I cleaned and lubricated the compressor itself, and it spins freely >and doesn't appear to be binding or otherwise have excessive friction. >The check valve/unloader is working and the piping is all open and >clear. > >It seems like the electric motor (1/3 hp) just no longer has the oomph >it used to. It starts up fine, no humming, no smoking, no bad smells, >no clunks. It just doesn't seem to have enough running torque to >handle the load like it did before. > >Anyone have any ideas? > Check the line voltage while opperating at the motor. I can do that stall with a long extension cord. greg |