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Default Air Compressor Problem - Motor Stalls


From the original post that started this thread:

... 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..."


Yes, those're the symptoms.


So it stalls first, then the unloader bleeds off pressure at the
compressor and allows it to restart?

I'm puzzled, but at this point I would disable the switch and unloader
and see if the compressor runs up to 120 as it used to.

You said the motor current is only 5 or 6 amps when it stalls?
Locked-rotor current for a 1/3HP motor should be much more than that,
at least 30 amps (I haven't looked it up). You're sure it's getting
full line voltage at that point? I don't see how it could be.

Alan
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Default Air Compressor Problem - Motor Stalls

On Mon, 08 Mar 2010 01:04:59 GMT, lid (Sparks
Fergusson) wrote:

PeterD wrote:

Typical small compressors the unloader opens when the pressure switch
activates and shuts off the compressor. This releases all pressure on
the compressor head, allowing the motor to start when pressure drops
down to the cutin PSI.


On this compressor, the check valve/unloader is completely separate
from the pressure switch. The unloader is similar to this one:
http://www.amazon.com/Control-Device...nloader-Check/


The URL above is 'dead'...

This is probably what you are trying to point to:

http://www.amazon.com/Control-Device...8055829&sr=8-1


IHMO it has not been said that the motor is stalling! A stalled motor
(called locked rotor) will cause input current to swing sky-high,
usually tripping the breaker, making a hell of a noise, and is very
obvious.


The voltage to the motor is never interrupted during the stop/start
cycle. Above a certain psi (about 95), the motor starts bogging down
and eventually stops. This occurs even if I bypass the pressure switch
and attach the cord directly to the motor leads. Then, after the
unloader vents the pressure, the motor will restart.


So the motor actually stalls, and there are no sounds (humming, etc.)
from it?


Input current does not swing sky-high, though, nor does the breaker
trip, nor is there a hell of a noise. It definitely comes to a dead
stop, though.


A most interesting set of symptoms... Motor stalls to locked rotor, no
significant current draw, odd...

How 'hot' is the motor? Is it possible the thermal cutout is tripping
(at too low a temperature, perhaps?)

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Default Air Compressor Problem - Motor Stalls

On Sun, 07 Mar 2010 21:56:03 -0500, Alan Douglas
wrote:


From the original post that started this thread:

... 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..."


Yes, those're the symptoms.


So it stalls first, then the unloader bleeds off pressure at the
compressor and allows it to restart?

I'm puzzled, but at this point I would disable the switch and unloader
and see if the compressor runs up to 120 as it used to.

You said the motor current is only 5 or 6 amps when it stalls?
Locked-rotor current for a 1/3HP motor should be much more than that,
at least 30 amps (I haven't looked it up). You're sure it's getting
full line voltage at that point? I don't see how it could be.

Alan


Well, he did say (in another post) he's bypassed the pressure switch
for a test run, and the symptoms persist. I think he's got a high
resistance point in the wiring too, but I'm not sure where.

Maybe monitor voltage at the motor terminals might give a clue.

As Alan says, locked rotor should result in very high current/power
draws. It is very noticable, and unless the compressor is on a circuit
that is vastly overfused result in a blown fuse/tripped breaker almost
immediately.

Can you (the OP) post specicifications from the motor's name plate,
and the compressor assembly? FWIW, no compressor has a fractional HP
motor, most are motors rated at 1 to 3 HP on small compressors.
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Default Air Compressor Problem - Motor Stalls


Sparks Fergusson wrote:

I only see one capacitor, so I'm assuming it's in the starting
circuit. I don't have a wiring diagram, and GE has no information on
it's website for this motor.



Don't assume. What is the capacitance? Some small split phase
motors only have a run capacitor. The fact that the current only rises
slightly indicates a bad capacitor or a poor connection to one winding.


--
Greed is the root of all eBay.
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Default Air Compressor Problem - Motor Stalls

In article , "Michael A. Terrell" wrote:

Sparks Fergusson wrote:

I only see one capacitor, so I'm assuming it's in the starting
circuit. I don't have a wiring diagram, and GE has no information on
it's website for this motor.



Don't assume. What is the capacitance? Some small split phase
motors only have a run capacitor. The fact that the current only rises
slightly indicates a bad capacitor or a poor connection to one winding.


I don't think GE is making the motors anymore, and thats why you can't
get info. Either test the cap or replace it. Its probably a run cap.

greg


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Default Air Compressor Problem - Motor Stalls

The main problem is that the motor is being overloaded. As mentioned
already, induction motors don't get tired or exhibit lower power output with
age.

You don't state some of the most essential info.. namely, the brand name and
model number of the air compressor, and the size and type of air pump.
The complete info listed on the motor label should also be included.

We can't see it from where we are.

Forget the capacitor.. the motor is starting normally, so the cap isn't the
problem.

A mechanical failure in the motor may be contributing to the overload. The
motor bearings may be worn out, they're likely to be sleeve bearings in a
1/3 HP motor, and not replaceable, but all hope is not lost if the motor
shaft isn't scored.
FWIW, sleeve bearings can wear to the extent that the rotor begins to rub on
the stator segments (lots of friction and excess heat).
If the bearing surfaces aren't completely wiped out, re-orienting the end
bells of the motor may provide better bearing surfaces. If the bearings are
the sleeve type, and haven't been oiled regularly, it's likely they would be
worn or damaged.

I can't positively explain why the motor isn't already destroyed, or why the
circuit breaker isn't tripping.

It's very likely that the overloading of the motor is related to air
pressure from the tank resisting movement of the piston in the pump, if the
pump is a piston-type pump.
Normally on small air compressors, tank pressure is isolated from the piston
by a check valve at the tank fitting.
Additionally, (in a piston air pump) there are likely to be reed valves in
the head of the air pump that would separate the cylinder from the outlet
fitting (the tubing constitutes a manifold in air compressor nomenclaure, if
the unit doesn't have a separate part designated as a manifold).
If the air intake is restricted (or choked off from a clogged filter as many
small air compressors only have a piece of wool felt filters), this may
contribute to more load on the motor.

Many piston air pumps have oil lubrication in the pump's case. If the oil
becomes very dirty or the level is inadequate, bearings, the pison and
cylinder can be damaged, resulting in excess friction until a full failure
takes place.

It's possible that the motor's thermal protector is responding to high
current, and if this is the case in this particular situation, it's the
reason the circui breaker hasn't tripped, and likely saved the motor from
destruction.
It's fairly obvious that the restarting actions described are the result of
a self-resetting protective device.

With the power cord unplugged, and the belt removed from the air pump (if
it's a piston-type pump), the pumping action can be checked by placing a
finger over the outlet fitting and briskly turning the pump pulley by hand.
The pump's basic operations of intake and compress/ouput can be observed
with this fairly simple test.

Some of the same conditions included above may pertain to diaphram-type air
pumps, although many diaphram types are direct drive, where the motor and
pump are a single unit, which may make checking the pump's basic operation a
little more difficult.

--
Cheers,
WB
..............



"Sparks Fergusson" wrote in message
...

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...

snippage

Anyone have any ideas?

Thanks!


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Default Air Compressor Problem - Motor Stalls

On Mon, 08 Mar 2010 08:58:34 -0500, PeterD wrote:

On Sun, 07 Mar 2010 21:56:03 -0500, Alan Douglas
wrote:


From the original post that started this thread:

... 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..."

Yes, those're the symptoms.


So it stalls first, then the unloader bleeds off pressure at the
compressor and allows it to restart?

I'm puzzled, but at this point I would disable the switch and unloader
and see if the compressor runs up to 120 as it used to.

You said the motor current is only 5 or 6 amps when it stalls?
Locked-rotor current for a 1/3HP motor should be much more than that,
at least 30 amps (I haven't looked it up). You're sure it's getting
full line voltage at that point? I don't see how it could be.

Alan


Well, he did say (in another post) he's bypassed the pressure switch
for a test run, and the symptoms persist. I think he's got a high
resistance point in the wiring too, but I'm not sure where.

Maybe monitor voltage at the motor terminals might give a clue.

As Alan says, locked rotor should result in very high current/power
draws. It is very noticable, and unless the compressor is on a circuit
that is vastly overfused result in a blown fuse/tripped breaker almost
immediately.

Can you (the OP) post specicifications from the motor's name plate,
and the compressor assembly? FWIW, no compressor has a fractional HP
motor, most are motors rated at 1 to 3 HP on small compressors.


Additional comment. The five amps draw is perhaps normal for this
unit, as it appears to be a 240 volt setup. I was thinking it was 120
volt (US) but I appear to be wrong there... g

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Default Air Compressor Problem - Motor Stalls

PeterD wrote:

This is probably what you are trying to point to:

http://www.amazon.com/Control-Device...8055829&sr=8-1


Sorry, yes, that's the one.

So the motor actually stalls, and there are no sounds (humming, etc.)
from it?


Yes, it actually stalls. There's not super loud humming. There may be
some motor noise, but it's hard to hear over the sound of the
unloader.

A most interesting set of symptoms... Motor stalls to locked rotor, no
significant current draw, odd...

How 'hot' is the motor? Is it possible the thermal cutout is tripping
(at too low a temperature, perhaps?)


Well, it does get warm. It gets warm when running with the belt off,
too. When it goes into it's stall cycle, it's definitely warmer than
that. I can put my Mk I hand on it for about 8 seconds, which says
it's hot, but not super hot.
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Default Air Compressor Problem - Motor Stalls

Alan Douglas wrote:


So it stalls first, then the unloader bleeds off pressure at the
compressor and allows it to restart?


Yes, that's correct.

I'm puzzled, but at this point I would disable the switch and unloader
and see if the compressor runs up to 120 as it used to.


It's a mechanical unloader, integrated with the check valve, so
disabling it would be difficult. However, it's pretty obvious that the
unloader only opens after the motor stalls when the check valve
closes.

You said the motor current is only 5 or 6 amps when it stalls?
Locked-rotor current for a 1/3HP motor should be much more than that,
at least 30 amps (I haven't looked it up). You're sure it's getting
full line voltage at that point? I don't see how it could be.


There's definitely no current spike when it stalls, nor does it trip
the breaker, dim the lights, etc. Is it getting full voltage? It is at
the point the motor leads connect to the pressure switch. I can't
easily measure any closer than that because the leads run into the
motor and there's no easy way to get to them, especially when it's
running. But, it looks like I need to disassemble the motor and check
things out inside, so that'll be the next step.

Thanks!


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Default Air Compressor Problem - Motor Stalls

PeterD wrote:

Well, he did say (in another post) he's bypassed the pressure switch
for a test run, and the symptoms persist. I think he's got a high
resistance point in the wiring too, but I'm not sure where.


Yes, bypassing the pressure switch doesn't make any diffence. You may
well be right about a high resistance point.

Maybe monitor voltage at the motor terminals might give a clue.


I can't easily get to the internal terminals. The closest I can
measure is at the pressure switch, and the voltage looks fine there.

As Alan says, locked rotor should result in very high current/power
draws. It is very noticable, and unless the compressor is on a circuit
that is vastly overfused result in a blown fuse/tripped breaker almost
immediately.


It's on a standard outlet circuit with a 20A breaker. It hasn't
tripped. Nor have there been any of the signs that you mention for
high current draw.

Can you (the OP) post specicifications from the motor's name plate,
and the compressor assembly? FWIW, no compressor has a fractional HP
motor, most are motors rated at 1 to 3 HP on small compressors.


1/3 HP is what's on the nameplate. These days, it would probably be
rated at 1 or 2 "marketing HP" :-)

The compressor itself has long lost it's label. But, it's a single
cylinder reciprocating, belt driven compressor with about a 20 gallon
tank, a 3 inch pulley on the motor and a 9 inch on the compressor.

The motor was made by GE, and is labeled:

Model: 5KC42JG391AX
Volts: 115/230
Ph: 1
Amps: 6.0/3.0
HP: 1/3
HZ: 60
RPM: 1725

It's running on 120 volts.


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Default Air Compressor Problem - Motor Stalls

David wrote:

The problem turned out to be that wasps had plugged up the air input
holes with mud. Cleaned out the mud and away she went


Darn mud daubers! Not the issue with mine, though.

Thanks!

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Default Air Compressor Problem - Motor Stalls

On Thu, 04 Mar 2010 05:13:31 GMT, lid (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!

After reading all the posts, several things stand out. The most
significant: There is no excessive current draw when the motor stalls.
By all the laws of physics, that is flat out impossible. There are
two explanations (well, three, but I'm assuming you aren't making this
up). The first is slippage at the belt, motor pulley, or rotor.
Given the knowledge you have exhibited, I say that can't be the
problem; it's pretty hard to miss the fact that the motor is spinning
but the belt is slipping.

That leads to only one conclusion: The actual voltage to the windings
is dropping. Possible causes are a bad thernal overload protector,
bad run capacitor (some motors hide the starting capacitor inside,
while the run capacitor is in a cupola on the side), or a corroded
terminal so only one of the paired windings is used.

All of these possible causes result in a lot of heat generated at
one small point EXCEPT the single winding and the bad run capacitor.
The single winding explanation is unlikely because it would not
deteriorate gradually. That leaves the bad run capacitor.

PlainBill
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Default Air Compressor Problem - Motor Stalls



wrote in message
...
On Thu, 04 Mar 2010 05:13:31 GMT, lid
(Sparks
Fergusson) wrote:
After reading all the posts, several things stand out.
The most
significant: There is no excessive current draw when the
motor stalls.
By all the laws of physics, that is flat out impossible.
There are
two explanations (well, three, but I'm assuming you aren't
making this
up). The first is slippage at the belt, motor pulley, or
rotor.
Given the knowledge you have exhibited, I say that can't
be the
problem; it's pretty hard to miss the fact that the motor
is spinning
but the belt is slipping.

That leads to only one conclusion: The actual voltage to
the windings
is dropping. Possible causes are a bad thernal overload
protector,
bad run capacitor (some motors hide the starting capacitor
inside,
while the run capacitor is in a cupola on the side), or a
corroded
terminal so only one of the paired windings is used.

All of these possible causes result in a lot of heat
generated at
one small point EXCEPT the single winding and the bad run
capacitor.
The single winding explanation is unlikely because it
would not
deteriorate gradually. That leaves the bad run capacitor.

PlainBill


There is one more possible cause: Some or all of the
windings on the rotor that are supposed to be shorted are
open. An induction motor works because windings on the rotor
are shorted to induce the field needed to turn the rotor.

David


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Default Air Compressor Problem - Motor Stalls

David Inscribed thus:



wrote in message
...
On Thu, 04 Mar 2010 05:13:31 GMT, lid
(Sparks
Fergusson) wrote:
After reading all the posts, several things stand out.
The most
significant: There is no excessive current draw when the
motor stalls.
By all the laws of physics, that is flat out impossible.
There are
two explanations (well, three, but I'm assuming you aren't
making this
up). The first is slippage at the belt, motor pulley, or
rotor.
Given the knowledge you have exhibited, I say that can't
be the
problem; it's pretty hard to miss the fact that the motor
is spinning
but the belt is slipping.

That leads to only one conclusion: The actual voltage to
the windings
is dropping. Possible causes are a bad thernal overload
protector,
bad run capacitor (some motors hide the starting capacitor
inside,
while the run capacitor is in a cupola on the side), or a
corroded
terminal so only one of the paired windings is used.

All of these possible causes result in a lot of heat
generated at
one small point EXCEPT the single winding and the bad run
capacitor.
The single winding explanation is unlikely because it
would not
deteriorate gradually. That leaves the bad run capacitor.

PlainBill


There is one more possible cause: Some or all of the
windings on the rotor that are supposed to be shorted are
open. An induction motor works because windings on the rotor
are shorted to induce the field needed to turn the rotor.

David


Thats a possibility, I've seen open rotor bars on induction motors.
Sometimes they arc at the break and leave burn marks.

--
Best Regards:
Baron.
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Default Air Compressor Problem - Motor Stalls

On Thu, 18 Mar 2010 15:58:38 -0500, "David"
wrote:



wrote in message
.. .
On Thu, 04 Mar 2010 05:13:31 GMT, lid
(Sparks
Fergusson) wrote:
After reading all the posts, several things stand out.
The most
significant: There is no excessive current draw when the
motor stalls.
By all the laws of physics, that is flat out impossible.
There are
two explanations (well, three, but I'm assuming you aren't
making this
up). The first is slippage at the belt, motor pulley, or
rotor.
Given the knowledge you have exhibited, I say that can't
be the
problem; it's pretty hard to miss the fact that the motor
is spinning
but the belt is slipping.

That leads to only one conclusion: The actual voltage to
the windings
is dropping. Possible causes are a bad thernal overload
protector,
bad run capacitor (some motors hide the starting capacitor
inside,
while the run capacitor is in a cupola on the side), or a
corroded
terminal so only one of the paired windings is used.

All of these possible causes result in a lot of heat
generated at
one small point EXCEPT the single winding and the bad run
capacitor.
The single winding explanation is unlikely because it
would not
deteriorate gradually. That leaves the bad run capacitor.

PlainBill


There is one more possible cause: Some or all of the
windings on the rotor that are supposed to be shorted are
open. An induction motor works because windings on the rotor
are shorted to induce the field needed to turn the rotor.

David

I've never seen that, but it is definitely a possibility and would
also explain the symtoms.

PlainBill
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Default Air Compressor Problem - Motor Stalls



wrote in message
...
On Thu, 18 Mar 2010 15:58:38 -0500, "David"

wrote:



wrote in message
. ..
On Thu, 04 Mar 2010 05:13:31 GMT,
lid
(Sparks
Fergusson) wrote:
After reading all the posts, several things stand out.
The most
significant: There is no excessive current draw when the
motor stalls.
By all the laws of physics, that is flat out impossible.
There are
two explanations (well, three, but I'm assuming you
aren't
making this
up). The first is slippage at the belt, motor pulley,
or
rotor.
Given the knowledge you have exhibited, I say that can't
be the
problem; it's pretty hard to miss the fact that the
motor
is spinning
but the belt is slipping.

That leads to only one conclusion: The actual voltage
to
the windings
is dropping. Possible causes are a bad thernal overload
protector,
bad run capacitor (some motors hide the starting
capacitor
inside,
while the run capacitor is in a cupola on the side), or
a
corroded
terminal so only one of the paired windings is used.

All of these possible causes result in a lot of heat
generated at
one small point EXCEPT the single winding and the bad
run
capacitor.
The single winding explanation is unlikely because it
would not
deteriorate gradually. That leaves the bad run
capacitor.

PlainBill


There is one more possible cause: Some or all of the
windings on the rotor that are supposed to be shorted are
open. An induction motor works because windings on the
rotor
are shorted to induce the field needed to turn the rotor.

David

I've never seen that, but it is definitely a possibility
and would
also explain the symtoms.

PlainBill


PlainBill:
I once saw a fractional HP induction motor on a fan had
problems starting in a certain position. After moving the
rotor a bit, it would run. There was one open winding on the
rotor. The open was visible on the side of the rotor and
applying a significant amount of solder cured the problem.
There can be a lot of current in these shorted turns on a
loaded motor.

David




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Default Air Compressor Problem - Motor Stalls

In article , wrote:
On Thu, 18 Mar 2010 15:58:38 -0500, "David"
wrote:



wrote in message
. ..
On Thu, 04 Mar 2010 05:13:31 GMT,
lid
(Sparks
Fergusson) wrote:
After reading all the posts, several things stand out.
The most
significant: There is no excessive current draw when the
motor stalls.
By all the laws of physics, that is flat out impossible.
There are
two explanations (well, three, but I'm assuming you aren't
making this
up). The first is slippage at the belt, motor pulley, or
rotor.
Given the knowledge you have exhibited, I say that can't
be the
problem; it's pretty hard to miss the fact that the motor
is spinning
but the belt is slipping.

That leads to only one conclusion: The actual voltage to
the windings
is dropping. Possible causes are a bad thernal overload
protector,
bad run capacitor (some motors hide the starting capacitor
inside,
while the run capacitor is in a cupola on the side), or a
corroded
terminal so only one of the paired windings is used.

All of these possible causes result in a lot of heat
generated at
one small point EXCEPT the single winding and the bad run
capacitor.
The single winding explanation is unlikely because it
would not
deteriorate gradually. That leaves the bad run capacitor.

PlainBill


There is one more possible cause: Some or all of the
windings on the rotor that are supposed to be shorted are
open. An induction motor works because windings on the rotor
are shorted to induce the field needed to turn the rotor.

David

I've never seen that, but it is definitely a possibility and would
also explain the symtoms.

PlainBill



With all the talk, I would have liked to hear the final answer to
the story. Is the compressor working yet. Its
been a long time.

greg
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Default (Solved!) Air Compressor Problem - Motor Stalls

"Wild_Bill" wrote:

The main problem is that the motor is being overloaded. As mentioned
already, induction motors don't get tired or exhibit lower power output with
age.


It's taken longer than I hoped, but I have finally put my air
compressor motor back together and it's working again!

To review, over time, the compressor had developed a problem of the
motor stalling before it reached full pressure.

Bearing in mind everyone's suggestions, I took the motor apart and
found that the bearings looked good, there was no sign of rotor/stator
contact, and the internal wiring and connections looked OK. The only
obvious problem was somewhat burned contacts on the centrifugal
switch.

Unfortunately, as I was taking it apart, I broke the voltage selector
switch, and that's what's taken me so long to get around to fixing.

Finally, with some JB weld and spare circuit board material, I managed
to glue the switch pieces back together.

I then cleaned and reseated all the internal connectors. I measured
all the windings for continuity or shorts (they looked good.) I
installed a new start cap, lubricated, and reassembled the motor.

It ran, but wouldn't start. After disassembling it again, and some
careful bending of the centrifugal switch, it was starting and running
smoothly.

Then, the moment of truth, I put the pulley and belt back on and fired
it up. As I carefully watched the pressure gauge, I kept adjusting the
regulator upwards. I ran it up to 140psi, and there was no sign of
stalling or even slowing down! Success!

I then adjusted the regulator back down to 120psi and buttoned
everything back up.

So, thanks to one and all for your help and suggestions. I'm back in
business!

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Default (Solved!) Air Compressor Problem - Motor Stalls

It ran, but wouldn't start.

Am I missing something?




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Default (Solved!) Air Compressor Problem - Motor Stalls

William Sommerwerck wrote:
It ran, but wouldn't start.


Am I missing something?



Yeah, you can yank the pulley to get the motor turning, then
it runs. But it won't start turning on it's own.

Jeff

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Default Air Compressor Problem - Motor Stalls

On Wednesday, March 3, 2010 at 9:13:31 PM UTC-8, 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!


Just replaced a "run capacitor on my 5 H.P. Champion compressor that was having a similar issue...All is well now.
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Default Air Compressor Problem - Motor Stalls

On Wednesday, October 21, 2015 at 4:52:53 PM UTC-4, wrote:

Just replaced a "run capacitor on my 5 H.P. Champion compressor that was having a similar issue...All is well now.


Yes!

This will very most likely be the problem. The motor is an AC induction motor, no brushes. But the run capacitor is critical to proper torque. And, if you are already in there and the happens to be a start-cap, do that one too.

Peter Wieck
Melrose Park, PA
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