We were using our Emglo and shut it down for a lunch break. When we came
back and tried to start it again all we got was a load electrical hum and
sometimes it would pop our 15 amp breaker.

I pulled the compressor/electric motor unit loose from the rest of the
compressor so I could get to its guts. When I turned the fan blade by hand
(it turned very easily) I could hear the compressor piston working. I even
connected the AC power back up but still heard the hum. When I gave the fan
a twist the motor started running the compressor. However, the motor won't
start the compressor on its own.

I tried a quick test of the start-up capacitor with my multimeter and it
appears to be OK. It slowly climbs in ohms until infinity. Reversed the
probes and it does the same thing. Sounds like the capacitor is OK to me.

I wanted to pull the electric motor loose from the case so I could see the
brushes and rotor. I removed all the mounting screws from everything I
could see, but I can't seem to pull the unit apart to get to the motor.
Everything is loose and I can twist the case a few degrees, but I can't pull
it apart.

Anybody know how I can get the motor out so I can look at its guts. Any
help is appreciated. Pretend I'm a dunce and be pretty specific.

Thanks,
Mike

Just because a cap doesn't leak at the low voltage provided by a VOM
does not mean it isn't leaking at working voltage. Try substituting
another cap and see if it helps. My outside air conditioning unit was
doing exactly the same thing. Diagnosis: bad starting cap. If your
motor uses two caps (one for start, one for run) check the centrufugal
switch
that controls the caps to see if it is broken.
Good luck. 73 Gary

Mike S. wrote:

We were using our Emglo and shut it down for a lunch break. When we came
back and tried to start it again all we got was a load electrical hum and
sometimes it would pop our 15 amp breaker.

I pulled the compressor/electric motor unit loose from the rest of the
compressor so I could get to its guts. When I turned the fan blade by hand
(it turned very easily) I could hear the compressor piston working. I even
connected the AC power back up but still heard the hum. When I gave the fan
a twist the motor started running the compressor. However, the motor won't
start the compressor on its own.

I tried a quick test of the start-up capacitor with my multimeter and it
appears to be OK. It slowly climbs in ohms until infinity. Reversed the
probes and it does the same thing. Sounds like the capacitor is OK to me.

I wanted to pull the electric motor loose from the case so I could see the
brushes and rotor. I removed all the mounting screws from everything I
could see, but I can't seem to pull the unit apart to get to the motor.
Everything is loose and I can twist the case a few degrees, but I can't pull
it apart.

Anybody know how I can get the motor out so I can look at its guts. Any
help is appreciated. Pretend I'm a dunce and be pretty specific.

Thanks,
Mike



It's probably still the start cap. Given the relatively low expense of
electrolytic capacitors, I'd just replace the start cap and see if that fixes
it. My guess is it will.

Take off the "bubble" on the side of the motor and look at the start cap. It may
obviously be defective, or maybe you can just get the numbers off it and take
them to Grainger or wherever you go to buy a new one. Easy to splice it back in,
simple fix. Even if that isn't the problem it won't hurt and it will probably
only cost you like $7.

GWE

The only thing I can think of is the unloader (if your compressor has one).
If it's sticking, there may be too much back pressure, and the motor isn't
powerful enough to overcome it.

"Ignoramus26433" wrote in message
...
Like others, I cannot think of anything beside the cap.

i

On Sun, 15 Jan 2006 15:53:43 -0800, Mike S. wrote:
We were using our Emglo and shut it down for a lunch break. When we
came
back and tried to start it again all we got was a load electrical hum
and
sometimes it would pop our 15 amp breaker.

I pulled the compressor/electric motor unit loose from the rest of the
compressor so I could get to its guts. When I turned the fan blade by
hand
(it turned very easily) I could hear the compressor piston working. I
even
connected the AC power back up but still heard the hum. When I gave the
fan
a twist the motor started running the compressor. However, the motor
won't
start the compressor on its own.

I tried a quick test of the start-up capacitor with my multimeter and it
appears to be OK. It slowly climbs in ohms until infinity. Reversed
the
probes and it does the same thing. Sounds like the capacitor is OK to
me.

I wanted to pull the electric motor loose from the case so I could see
the
brushes and rotor. I removed all the mounting screws from everything I
could see, but I can't seem to pull the unit apart to get to the motor.
Everything is loose and I can twist the case a few degrees, but I can't
pull
it apart.

Anybody know how I can get the motor out so I can look at its guts. Any
help is appreciated. Pretend I'm a dunce and be pretty specific.

Thanks,
Mike




--

On Sun, 15 Jan 2006 15:53:43 -0800, "Mike S." wrote:

We were using our Emglo and shut it down for a lunch break. When we came
back and tried to start it again all we got was a load electrical hum and
sometimes it would pop our 15 amp breaker.

I pulled the compressor/electric motor unit loose from the rest of the
compressor so I could get to its guts. When I turned the fan blade by hand
(it turned very easily) I could hear the compressor piston working. I even
connected the AC power back up but still heard the hum. When I gave the fan
a twist the motor started running the compressor. However, the motor won't
start the compressor on its own.

I tried a quick test of the start-up capacitor with my multimeter and it
appears to be OK. It slowly climbs in ohms until infinity. Reversed the
probes and it does the same thing. Sounds like the capacitor is OK to me.

I wanted to pull the electric motor loose from the case so I could see the
brushes and rotor. I removed all the mounting screws from everything I
could see, but I can't seem to pull the unit apart to get to the motor.
Everything is loose and I can twist the case a few degrees, but I can't pull
it apart.

Anybody know how I can get the motor out so I can look at its guts. Any
help is appreciated. Pretend I'm a dunce and be pretty specific.

Thanks,
Mike

There aren't any brushes in an AC induction motor.

Disconnect the start cap and check both leads for continuity to the
plug or mains connection (with it unplugged, of course!) You should
see continuity from both cap connections to both line connections,
though the (low) resistances will be different. If one of them
check open, there's your problem.

The most likely cause is a failed centrifugal start switch.

Hope someone can tell you how to get the motor loose.

Most capacitor start motors have t

Gary,

Thanks for the input. I'll try to find somebody local that can do a
heavy-duty test on this cap.

Mike

Hi Grant,

It's probably still the start cap. Given the relatively low expense of
electrolytic capacitors, I'd just replace the start cap and see if that
fixes
it. My guess is it will.

Take off the "bubble" on the side of the motor and look at the start cap.
It may
obviously be defective, or maybe you can just get the numbers off it and
take
them to Grainger or wherever you go to buy a new one. Easy to splice it
back in,
simple fix. Even if that isn't the problem it won't hurt and it will
probably
only cost you like $7.

Well, not quite. I've been told by two repair houses that this cap costs
$50. I want to make sure it's dead before I replace it.

Thanks,
Mike

Hi Bob,

The only thing I can think of is the unloader (if your compressor has
one).
If it's sticking, there may be too much back pressure, and the motor isn't
powerful enough to overcome it.

Don't think that's the case. When I removed the compressor/motor unit from
the rest of the compressor it also removed it from all the air tanks etc.
Like I said, spinning the compressor by hand was very easy. Its just that
the motor won't start on its own.

Thanks,
Mike

In article ,
Mike S. wrote:
Hi Bob,

The only thing I can think of is the unloader (if your compressor has
one).
If it's sticking, there may be too much back pressure, and the motor isn't
powerful enough to overcome it.

Don't think that's the case. When I removed the compressor/motor unit from
the rest of the compressor it also removed it from all the air tanks etc.
Like I said, spinning the compressor by hand was very easy. Its just that
the motor won't start on its own.

That virtually guarantees that the problem is one of two things:
1) stuck/bad (open) centrifugal switch for the start windings on the motor
2) bad start cap.


I'd be tempted to try some 'impact engineering' to see if one can induce
the centrifugal switch to close. Proceed at your own risk. grin

In article ,
Ignoramus7637 wrote:

I am surprised about the cost of caps that you were quoted. They
actually should cost a lot less. I have a few start caps that I bought
new for like $3 apiece, each about 180 uF. I can sell you a couple for
the same price, I have too many. If you arer local to Chicagoland, I
can loan you some.

Can you remove belt (if it is a belted compressor) and see if the
motor starts by itself without a load?

Another test is to put a pull rope in the pulley (with no compressor),
turn the AC power on, and try to start it like a gasoline engine. Or a
RPC without pony motor or caps.

Joe Gwinn

We were using our Emglo and shut it down for a lunch break. When we came
back and tried to start it again all we got was a load electrical hum and
sometimes it would pop our 15 amp breaker.

I pulled the compressor/electric motor unit loose from the rest of the
compressor so I could get to its guts. When I turned the fan blade by hand
(it turned very easily) I could hear the compressor piston working. I even
connected the AC power back up but still heard the hum. When I gave the fan
a twist the motor started running the compressor. However, the motor won't
start the compressor on its own.

I tried a quick test of the start-up capacitor with my multimeter and it
appears to be OK. It slowly climbs in ohms until infinity. Reversed the
probes and it does the same thing. Sounds like the capacitor is OK to me.

I wanted to pull the electric motor loose from the case so I could see the
brushes and rotor. I removed all the mounting screws from everything I
could see, but I can't seem to pull the unit apart to get to the motor.
Everything is loose and I can twist the case a few degrees, but I can't pull
it apart.

Anybody know how I can get the motor out so I can look at its guts. Any
help is appreciated. Pretend I'm a dunce and be pretty specific.

Thanks,
Mike


Probably starting switch inside the motor that connects the cap to the
windings. Try tapping on the end bell of the motor when you try to
start it.... The "points" eventually get a bit pitted and blackened,
and typically cleaning them up is all it will need....
HTH
Ken.

"Ignoramus7637" wrote in message
...
On Mon, 16 Jan 2006 21:02:59 -0500, Joseph Gwinn
wrote:
In article ,
Ignoramus7637 wrote:

I am surprised about the cost of caps that you were quoted. They
actually should cost a lot less. I have a few start caps that I bought
new for like $3 apiece, each about 180 uF. I can sell you a couple for
the same price, I have too many. If you arer local to Chicagoland, I
can loan you some.

Can you remove belt (if it is a belted compressor) and see if the
motor starts by itself without a load?

Another test is to put a pull rope in the pulley (with no compressor),
turn the AC power on, and try to start it like a gasoline engine. Or a
RPC without pony motor or caps.

Yes, that's a good test, but make sure that all rope is gone off the
shaft before you turn AC on (could sound obvious, but needs to be
said).


Lots easier just to give the pulley a spin by hand.

--

-Mike-

oh come on, mike - a cap costs $5 to $20, just change the stupid thing
- it's almost for sure the problem, and it's cheaper than spending all
week trying to test it.

On Mon, 16 Jan 2006 07:35:19 -0800, "Mike S." wrote:

Gary,

Thanks for the input. I'll try to find somebody local that can do a
heavy-duty test on this cap.

Mike

Bill

www.wbnoble.com

to contact me, do not reply to this message,
instead correct this address and use it

will iam_ b_ No ble at msn daught com

"Ignoramus7637" wrote in message
news
I am surprised about the cost of caps that you were quoted. They
actually should cost a lot less. I have a few start caps that I bought
new for like $3 apiece, each about 180 uF. I can sell you a couple for
the same price, I have too many. If you arer local to Chicagoland, I
can loan you some.

Can you remove belt (if it is a belted compressor) and see if the
motor starts by itself without a load?

No belt. And when the motor/compressor unit was sitting on the bench it
still wouldn't start. If I gave the motor fan a spin and applied power it
started to run - although the start up time was very slow.

Mike S.

"Mike Marlow" wrote in message
...

Lots easier just to give the pulley a spin by hand.


Already tried that. Motor starts, but very slowly.

Mike

That virtually guarantees that the problem is one of two things:
1) stuck/bad (open) centrifugal switch for the start windings on the
motor
2) bad start cap.


I'd be tempted to try some 'impact engineering' to see if one can induce
the centrifugal switch to close. Proceed at your own risk. grin

I'd be glad to check the centrifugal switch - if I knew what it was and
where it's located. It's not on my exploded view diagram.

Mike

Ken Sterling (Ken Sterling) wrote in message
...
Probably starting switch inside the motor that connects the cap to the
windings. Try tapping on the end bell of the motor when you try to
start it.... The "points" eventually get a bit pitted and blackened,
and typically cleaning them up is all it will need....
HTH
Ken.

So if that's the case, how do I get to them?

Mike

Ken Sterling (Ken Sterling) wrote in message
...
Probably starting switch inside the motor that connects the cap to the
windings. Try tapping on the end bell of the motor when you try to
start it.... The "points" eventually get a bit pitted and blackened,
and typically cleaning them up is all it will need....
HTH
Ken.

So if that's the case, how do I get to them?

Mike


Mike,
Having trouble finding any kind of info on that particular model -
AM78-HV4V...... From your original post, it sounds like this is just
a motor, with a pulley, driving a larger pulley via a belt, as you
mentioned giving the "fan" a spin. Anyway, ya gotta locate the motor,
and take the end bell off to gain access to a centrifugal switch
internal to the motor. The switch has a set of contact points on it
which close with the motor at rest, putting the cap into the circuit.
When the motor starts up, centrifugal force causes the switch to open
up and takes the cap out of the circuit until it's needed for the next
start. Arcing, pitting, dust, dirt, etc., can keep the contacts from
making contact with each other when the motor is at rest. I suggested
tapping on the end bell of the motor when trying to start it as
sometimes that will let the contacts actually touch each other and get
the cap in the circuit to start the motor. That will tell you if the
cap is good or not as well as letting you know that the contacts are
dirty. I can't see the motor so it's hard to tell you how to take it
apart. Sorry.
Ken.

If you were quoted $50 for a capacitor, I'd seriously try to find
another place to deal with - what exact value capacitor do you need?
did you check local electronics supply/surplus houses (be sure to say
it's a motor start capacitor) - the last one I bought (three days ago)
was 600 uf at 220VAC for $12, generally lower capacitance values are
less expensive.

Bill

www.wbnoble.com

to contact me, do not reply to this message,
instead correct this address and use it

will iam_ b_ No ble at msn daught com

Hi Bill,

Don't have it in front of me any more. Sent it home with my brother. But,
if memory serves me correctly it's 60uF, 360VAC. The repair shop quoted
$50.00, the Emglo (DeWalt?) website quoted $43.00. Pretty pricey item, I
guess.

Mike

replying to Mike S., josh wrote:
no wrote:

We were using our Emglo and shut it down for a lunch break. When we came
back and tried to start it again all we got was a load electrical hum and
sometimes it would pop our 15 amp breaker.
I pulled the compressor/electric motor unit loose from the rest of the
compressor so I could get to its guts. When I turned the fan blade by hand
(it turned very easily) I could hear the compressor piston working. I even
connected the AC power back up but still heard the hum. When I gave the
fan
a twist the motor started running the compressor. However, the motor won't
start the compressor on its own.
I tried a quick test of the start-up capacitor with my multimeter and it
appears to be OK. It slowly climbs in ohms until infinity. Reversed the
probes and it does the same thing. Sounds like the capacitor is OK to me.
I wanted to pull the electric motor loose from the case so I could see the
brushes and rotor. I removed all the mounting screws from everything I
could see, but I can't seem to pull the unit apart to get to the motor.
Everything is loose and I can twist the case a few degrees, but I can't
pull
it apart.
Anybody know how I can get the motor out so I can look at its guts. Any
help is appreciated. Pretend I'm a dunce and be pretty specific.
Thanks,
Mike


Mike, I know this is OLD, but did you ever find out how to get inside to
the centrifugal switch? I have one w/the same symptoms and I don't wanna
ruin a $50 cap if the switch is stuck closed.

--
posted from
http://www.polytechforum.com/metalwo...or-467755-.htm
using PolytechForum's Web, RSS and Social Media Interface to
rec.crafts.metalworking and other engineering groups

josh fired this
volley in oups.com:

When I gave the
fan
a twist the motor started running the compressor. However, the motor
won't start the compressor on its own.


You never said anything about checking the unloader valve.
The Emglo compressors ALL have unloader valves (most compressors do), and
the compressors don't have a hope of starting up with any residual
pressure in the tank unless it's working.

LLoyd

On 2014-03-29, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
josh fired this
volley in oups.com:

When I gave the
fan
a twist the motor started running the compressor. However, the motor
won't start the compressor on its own.


You never said anything about checking the unloader valve.
The Emglo compressors ALL have unloader valves (most compressors do), and
the compressors don't have a hope of starting up with any residual
pressure in the tank unless it's working.

Or -- assuming a single-phase induction motor -- the start cap
could be blown, so it does not get that initial motion necessary for
the induction to generate pole pieces in the right place to pull the
motor round. (I didn't see the original posting -- could he be in my
killfile somehow?)

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"DoN. Nichols" fired this volley in
:

Or -- assuming a single-phase induction motor -- the start cap
could be blown, so it does not get that initial motion necessary for
the induction to generate pole pieces in the right place to pull the
motor round. (I didn't see the original posting -- could he be in my
killfile somehow?)


He checked all that, Don. Then, just turning the motor over by HAND, it
would start... that tells me it was dead-heading against pressure.

Lloyd

replying to Lloyd E. Sponenburgh , josh wrote:
lol. the original question was also how to separate the motor from the
pump to inspect the centrifugal switch. pump won't start up correctly
with 0 psi.

please look:

http://www.ereplacementparts.com/emg...189_15192.html

the main shaft can't be pulled out either way that I can see. the fan has
no apparent connection. it looks like it was put on and the end of the
shaft was tooled somehow to keep it in place. if it was popped off, would
it be conceivable to be put back on?

--
posted from
http://www.polytechforum.com/metalwo...or-467755-.htm
using PolytechForum's Web, RSS and Social Media Interface to
rec.crafts.metalworking and other engineering groups

On 2014-03-30, josh wrote:
replying to Lloyd E. Sponenburgh , josh wrote:
lol. the original question was also how to separate the motor from the
pump to inspect the centrifugal switch. pump won't start up correctly
with 0 psi.

please look:

http://www.ereplacementparts.com/emg...189_15192.html

Looking at that (the downloaded PDF, not the reduced drawing
visible on the page) it does not appear to even *have* a centrifugal
switch. I see the cap (item 220, with associated mounting nut and
lockwasher), and the stator, with what *looks* like four leads coming
out, and no visible terminal block or anything of the sort, unless that
is part of the "end cover" (item 235).

It is *possible* that this thing has a capacitor *run* motor
instead of a capacitor *start* motor, so there would be *no* centrifugal
switch. Look at the capacitor to see whether it has a full AC voltage
rating or just a DC one. The photo of it is too low contrast and too
small to read the ratings on the cap from here, but you have the actual
cap to look at.

the main shaft can't be pulled out either way that I can see. the fan has
no apparent connection. it looks like it was put on and the end of the
shaft was tooled somehow to keep it in place. if it was popped off, would
it be conceivable to be put back on?

Is 236 (a nut) used to hold the end cover in place, or the fan?

There is also item 846, which is called a "repair kit", and
which appears to have a couple of screws, a nut and a washer, or perhaps
two sizes of nuts, and three wires (or are those wrinkles in the plastic
bag?)

It might also be possible (if enough wires go into the pressure
switch) that it closes all contacts and then releases some to take the
task of a centrifugal switch.

Whatever it is, it is a weird device.

And it looks as though it is rather noisy when it *is* working.

Good Luck,
Don.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

replying to DoN. Nichols , josh wrote:
BPdnicholsBP wrote:

Looking at that (the downloaded PDF, not the reduced drawing
visible on the page) it does not appear to even *have* a centrifugal
switch. I see the cap (item 220, with associated mounting nut and
lockwasher), and the stator, with what *looks* like four leads coming
out, and no visible terminal block or anything of the sort, unless that
is part of the "end cover" (item 235).

Thank you Don I didn't even see the detailed pdf. There are a total of 8
leads coming from the motor: a ground at motor, 2 leads to the capacitor,
2 to a overload switch, and 3 head to pressure switch. One of those in
pressure switch is ground.

It is *possible* that this thing has a capacitor *run* motor
instead of a capacitor *start* motor, so there would be *no* centrifugal
switch. Look at the capacitor to see whether it has a full AC voltage
rating or just a DC one. The photo of it is too low contrast and too
small to read the ratings on the cap from here, but you have the actual
cap to look at.

The cap is 250v 60uf. Does that indicate it's a capacitor 'run' motor? I
(for whatever reason) thought there would be another cap inside the end
cover with the motor.

Is 236 (a nut) used to hold the end cover in place, or the fan?

Nut-236 corresponds with bolt-230 which sandwiches the motor with the
crankcase-221 and end cover.

There is also item 846, which is called a "repair kit", and
which appears to have a couple of screws, a nut and a washer, or perhaps
two sizes of nuts, and three wires (or are those wrinkles in the plastic
bag?)

Yeah, that's a great illustration ain't it! Not sure what those are.

It might also be possible (if enough wires go into the pressure
switch) that it closes all contacts and then releases some to take the
task of a centrifugal switch.

Whatever it is, it is a weird device.
And it looks as though it is rather noisy when it *is* working.
Good Luck,
Don.

How'd you know it was a noisy bugger? I guess I'll bite the bullet and
order the cap and see how it performs. Thanks again Don.
Josh


--
posted from
http://www.polytechforum.com/metalwo...or-467755-.htm
using PolytechForum's Web, RSS and Social Media Interface to
rec.crafts.metalworking and other engineering groups

On 2014-04-02, josh wrote:
replying to DoN. Nichols , josh wrote:
BPdnicholsBP wrote:

Looking at that (the downloaded PDF, not the reduced drawing
visible on the page) it does not appear to even *have* a centrifugal

[ ... ]

Thank you Don I didn't even see the detailed pdf. There are a total of 8
leads coming from the motor: a ground at motor, 2 leads to the capacitor,
2 to a overload switch, and 3 head to pressure switch. One of those in
pressure switch is ground.

O.K. Hard to tell from that whether there is a centrifugal
switch hiding inside the housing -- but they sure don't list parts for
one.

It is *possible* that this thing has a capacitor *run* motor
instead of a capacitor *start* motor, so there would be *no* centrifugal
switch. Look at the capacitor to see whether it has a full AC voltage
rating or just a DC one. The photo of it is too low contrast and too
small to read the ratings on the cap from here, but you have the actual
cap to look at.

The cap is 250v 60uf. Does that indicate it's a capacitor 'run' motor? I
(for whatever reason) thought there would be another cap inside the end
cover with the motor.

Hmm ... what HP for the motor? I think that may be closer to
the value for a run cap instead of a start cap, but I'm not sure. Did
the rating on the cap say 250 VDC or 250 VAC? If it is an AC rating,
then it is likely a run cap -- and more expensive (and larger) than the
typical motor start cap.

[ ... ]

There is also item 846, which is called a "repair kit", and
which appears to have a couple of screws, a nut and a washer, or perhaps
two sizes of nuts, and three wires (or are those wrinkles in the plastic
bag?)

Yeah, that's a great illustration ain't it! Not sure what those are.

:-)

It might also be possible (if enough wires go into the pressure
switch) that it closes all contacts and then releases some to take the
task of a centrifugal switch.

Whatever it is, it is a weird device.
And it looks as though it is rather noisy when it *is* working.
Good Luck,
Don.

How'd you know it was a noisy bugger?

Direct drive compressors Tend to be very noisy. And oil free,
too?

I prefer belt drive oil wetted compressors -- even the small
ones are relatively quiet. Still not silent, but less likely to make
you throw something through the ceiling when they start up. :-)

I guess I'll bite the bullet and
order the cap and see how it performs. Thanks again Don.

No spare caps around the house to test it with? I guess that
your house is not like mine. :-)

And no way to measure the capacitance of the cap? For a very
coarse way, take an ohmmeter and see how long it takes to get to a
certain reading when you reverse the probes. Compare it to a smaller
voltage capacitor of the same nominal capacitance to see whether you're
in the ballpark.

You're welcome.

Good Luck,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---