Induction motor gone bipolar?

[David Farber]

I have an automatic gate which uses a GE 5KH36HN62T motor to open and close
the gate. The gate intermittently will not open. You can hear the motor buzz
and it will start moving if given a gentle push. The motor uses a capacitor
start circuit to get it going. The other fault with the motor is that
sometimes it turns in the wrong direction. This is my analysis of the
situation so correct me if I'm wrong. The fact that the motor buzzes and
will start turning with a gentle assist probably means there is a fault in
the start circuit. I tested the capacitors and they are ok. So I'm thinking
the internal motor start switch is sticking open. As far as the motor
occasionally turning the wrong direction, that too can be attributed to the
faulty start circuit because not only does the start circuit get the motor
going from a stopped position, it determines the direction that motor will
turn. If the load is light enough, the motor now may turn in either
direction if the start windings are not giving it its initial boost. Does
this make sense?

Thanks for your reply.
--
David Farber
David Farber's Service Center
L.A., CA

 

[William Sommerwerck]

Bipolar? Lubricate it with lithium grease!

 

[Samuel M. Goldwasser]

"David Farber" <farberbear.unspam@aol.com> writes:

I have an automatic gate which uses a GE 5KH36HN62T motor to open and close
the gate. The gate intermittently will not open. You can hear the motor buzz
and it will start moving if given a gentle push. The motor uses a capacitor
start circuit to get it going. The other fault with the motor is that
sometimes it turns in the wrong direction. This is my analysis of the
situation so correct me if I'm wrong. The fact that the motor buzzes and
will start turning with a gentle assist probably means there is a fault in
the start circuit. I tested the capacitors and they are ok. So I'm thinking
the internal motor start switch is sticking open. As far as the motor
occasionally turning the wrong direction, that too can be attributed to the
faulty start circuit because not only does the start circuit get the motor
going from a stopped position, it determines the direction that motor will
turn. If the load is light enough, the motor now may turn in either
direction if the start windings are not giving it its initial boost. Does
this make sense?

Probably a bad start cap or a fault in the starting circuit.

An induction motor without the starging winding energized will do exactly
as you describe - have no real preference for direction and no starting torque.

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
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| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

 

[David Farber]

Samuel M. Goldwasser wrote:

"David Farber" <farberbear.unspam@aol.com> writes:

I have an automatic gate which uses a GE 5KH36HN62T motor to open
and close the gate. The gate intermittently will not open. You can
hear the motor buzz and it will start moving if given a gentle push.
The motor uses a capacitor start circuit to get it going. The other
fault with the motor is that sometimes it turns in the wrong
direction. This is my analysis of the situation so correct me if I'm
wrong. The fact that the motor buzzes and will start turning with a
gentle assist probably means there is a fault in the start circuit.
I tested the capacitors and they are ok. So I'm thinking the
internal motor start switch is sticking open. As far as the motor
occasionally turning the wrong direction, that too can be attributed
to the faulty start circuit because not only does the start circuit
get the motor going from a stopped position, it determines the
direction that motor will turn. If the load is light enough, the
motor now may turn in either direction if the start windings are not
giving it its initial boost. Does this make sense?

Probably a bad start cap or a fault in the starting circuit.

An induction motor without the starging winding energized will do
exactly
as you describe - have no real preference for direction and no
starting torque.

Thanks Sam! That's the answer I was hoping for.

--
David Farber
David Farber's Service Center
L.A., CA

 

[Wild_Bill]

I didn't get any results by searching the GE number provided, but your
description sounds as though the motor is a common capacitor start
split-phase AC motor, David.

Some of these types of motors have 2 AC capacitors.. a higher value start
capacitor (typically over 100uF), and a low value run capacitor (generally
under 30uF)

The behavior you've described sounds as though there is a fault in the start
circuit, as you suspected, and Sam suggested.
These motors will exhibit the symptoms you experienced as far as humming
when they fail to spin up, but run when the shaft is spun by external means.

This type of motor consists of a start capacitor, in series with a start
winding, a start/run centrifugal switch, and a run winding.
At rest, the start winding (and series capacitor) is connected in parallel
with the run winding, by the centrifugal switch.

If your motor doesn't include a centrifugal switch, then it's a different
type of motor than a split-phase motor.

In properly operating capacitor start split-phase motor, when power is
applied, the start winding spins up the rotor, the weights of the
centrifugal switch overcome the tension of the springs associated with the
switch, and the switch opens, allowing the run winding to take over.
When the power is removed, the rotor begins to slow, then a distinct click
is heard, when the centrifugal mechanism resets as the rotor approaches the
lower switch point speed as it continues to coast to a stop.

These types of motors aren't instantly reversible. If for some reason power
is re-applied before the rotor stops (not the usual start/stop procedure),
the motor will continue to run in the same direction the rotor was coasting.
This is a characteristic of these motors, in that the rotor needs to stop
before power is re-applied. This is important for applications where the
motor is wired to be reversible.

For visual inspection, you'll want to examine the areas of the shaft where
the bearings are situated in the case of sleeve bearings. If the sleeve
bearings are worn, the motor may have to be replaced, as these aren't
usually a service part.
When the sleeve bearings are badly worn, it may be noticable by looking for
signs that the rotor has been contacting/rubbing on the sectors of the
stator.

Another important component is the centrifugal switch. If the contacts are
badly pitted and/or burnt from arcing, the switch should be replaced (if
it's available as service part). Some folks are comfortable with filing or
dressing the contacts with abrasives (emery or sandpaper), then burnishing
the contacts.
If the contacts' connection has become high in resistance due to pitting
from arcing, the motor could fail to spin up in the way you've described.

When these motors fail to spin up, a very likely cause is the start
capacitor.
Depending upon what type of tester was used, the results indicated when
testing AC capacitors may be inconclusive as to the quality of the
capacitor.
Testing the motor with a new AC capacitor is a better approach.

If a fault has developed within the start winding of the motor, the motor
will most likely have to be replaced.

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


"David Farber" <farberbear.unspam@aol.com> wrote in message
news:4a57b896$0$4078$bd467cd0@news.dslextreme.com...

I have an automatic gate which uses a GE 5KH36HN62T motor to open and close
the gate. The gate intermittently will not open. You can hear the motor
buzz and it will start moving if given a gentle push. The motor uses a
capacitor start circuit to get it going. The other fault with the motor is
that sometimes it turns in the wrong direction. This is my analysis of the
situation so correct me if I'm wrong. The fact that the motor buzzes and
will start turning with a gentle assist probably means there is a fault in
the start circuit. I tested the capacitors and they are ok. So I'm thinking
the internal motor start switch is sticking open. As far as the motor
occasionally turning the wrong direction, that too can be attributed to the
faulty start circuit because not only does the start circuit get the motor
going from a stopped position, it determines the direction that motor will
turn. If the load is light enough, the motor now may turn in either
direction if the start windings are not giving it its initial boost. Does
this make sense?

Thanks for your reply.
--
David Farber
David Farber's Service Center
L.A., CA

 

[Meat Plow]

On Fri, 10 Jul 2009 14:54:38 -0700, "David Farber"
<farberbear.unspam@aol.com>wrote:

I have an automatic gate which uses a GE 5KH36HN62T motor to open and close
the gate. The gate intermittently will not open. You can hear the motor buzz
and it will start moving if given a gentle push. The motor uses a capacitor
start circuit to get it going. The other fault with the motor is that
sometimes it turns in the wrong direction. This is my analysis of the
situation so correct me if I'm wrong. The fact that the motor buzzes and
will start turning with a gentle assist probably means there is a fault in
the start circuit. I tested the capacitors and they are ok. So I'm thinking
the internal motor start switch is sticking open. As far as the motor
occasionally turning the wrong direction, that too can be attributed to the
faulty start circuit because not only does the start circuit get the motor
going from a stopped position, it determines the direction that motor will
turn. If the load is light enough, the motor now may turn in either
direction if the start windings are not giving it its initial boost. Does
this make sense?

Thanks for your reply.

How did you test the start cap? If it's flaky it's not going to
advance the phase to start the motor and could possibly start
backwords.

 

[David Farber]

Meat Plow wrote:

On Fri, 10 Jul 2009 14:54:38 -0700, "David Farber"
farberbear.unspam@aol.com>wrote:

I have an automatic gate which uses a GE 5KH36HN62T motor to open
and close the gate. The gate intermittently will not open. You can
hear the motor buzz and it will start moving if given a gentle push.
The motor uses a capacitor start circuit to get it going. The other
fault with the motor is that sometimes it turns in the wrong
direction. This is my analysis of the situation so correct me if I'm
wrong. The fact that the motor buzzes and will start turning with a
gentle assist probably means there is a fault in the start circuit.
I tested the capacitors and they are ok. So I'm thinking the
internal motor start switch is sticking open. As far as the motor
occasionally turning the wrong direction, that too can be attributed
to the faulty start circuit because not only does the start circuit
get the motor going from a stopped position, it determines the
direction that motor will turn. If the load is light enough, the
motor now may turn in either direction if the start windings are not
giving it its initial boost. Does this make sense?

Thanks for your reply.

How did you test the start cap? If it's flaky it's not going to
advance the phase to start the motor and could possibly start
backwords.

I tested the caps with my Bob Parker ESR meter. There are two 130uF 330V
capacitors in parallel. I checked them out of circuit to make sure. I'm
fairly certain I tested them for shorts because the ESR was very low. I'm
going to have another visit with the gate this afternoon and specifically
test out the motor starting circuit.

Here is a schematic that I drew up a while back. Except for my head
scratching of what's energizing relay "B", I think the rest of the diagram
is accurate. It doesn't help that about 75% of the wires are all the same
color!

Schematic: http://www.pbase.com/mrfixit/image/81687434
For other pics of the electronics: http://www.pbase.com/mrfixit/gate

Thanks for your reply.
--
David Farber
David Farber's Service Center
L.A., CA

 

[David Farber]

"David Farber" <farberbear.unspam@aol.com> wrote in message
news:4a57b896$0$4078$bd467cd0@news.dslextreme.com...
I have an automatic gate which uses a GE 5KH36HN62T motor to open
and close the gate. The gate intermittently will not open. You can
hear the motor buzz and it will start moving if given a gentle push.
The motor uses a capacitor start circuit to get it going. The other
fault with the motor is that sometimes it turns in the wrong
direction. This is my analysis of the situation so correct me if I'm
wrong. The fact that the motor buzzes and will start turning with a
gentle assist probably means there is a fault in the start circuit.
I tested the capacitors and they are ok. So I'm thinking the
internal motor start switch is sticking open. As far as the motor
occasionally turning the wrong direction, that too can be attributed
to the faulty start circuit because not only does the start circuit
get the motor going from a stopped position, it determines the
direction that motor will turn. If the load is light enough, the
motor now may turn in either direction if the start windings are not
giving it its initial boost. Does this make sense? Thanks for your reply.

Wild_Bill wrote:

I didn't get any results by searching the GE number provided, but your
description sounds as though the motor is a common capacitor start
split-phase AC motor, David.

Some of these types of motors have 2 AC capacitors.. a higher value
start capacitor (typically over 100uF), and a low value run capacitor
(generally under 30uF)

The behavior you've described sounds as though there is a fault in
the start circuit, as you suspected, and Sam suggested.
These motors will exhibit the symptoms you experienced as far as
humming when they fail to spin up, but run when the shaft is spun by
external means.
This type of motor consists of a start capacitor, in series with a
start winding, a start/run centrifugal switch, and a run winding.
At rest, the start winding (and series capacitor) is connected in
parallel with the run winding, by the centrifugal switch.

If your motor doesn't include a centrifugal switch, then it's a
different type of motor than a split-phase motor.

In properly operating capacitor start split-phase motor, when power
is applied, the start winding spins up the rotor, the weights of the
centrifugal switch overcome the tension of the springs associated
with the switch, and the switch opens, allowing the run winding to
take over. When the power is removed, the rotor begins to slow, then a
distinct
click is heard, when the centrifugal mechanism resets as the rotor
approaches the lower switch point speed as it continues to coast to a
stop.

Interesting point about the "click." I do here click(s?) when the gate stops
moving. I had always thought the click was being caused by the mechanical
movement of the switching relays.

These types of motors aren't instantly reversible.
There is about a 30 second delay before the gate starts to automatically

close after reaching the fully open positioned. I don't think it is possible
for the rotor to continue to turn if the gate has stopped unless there is
some intermediate transmission in the motor itself.

If for some reason

power is re-applied before the rotor stops (not the usual start/stop
procedure), the motor will continue to run in the same direction the
rotor was coasting. This is a characteristic of these motors, in that
the rotor needs to stop before power is re-applied. This is important
for applications where the motor is wired to be reversible.

For visual inspection, you'll want to examine the areas of the shaft
where the bearings are situated in the case of sleeve bearings. If
the sleeve bearings are worn, the motor may have to be replaced, as
these aren't usually a service part.
When the sleeve bearings are badly worn, it may be noticable by
looking for signs that the rotor has been contacting/rubbing on the
sectors of the stator.

Another important component is the centrifugal switch. If the
contacts are badly pitted and/or burnt from arcing, the switch should
be replaced (if it's available as service part). Some folks are
comfortable with filing or dressing the contacts with abrasives
(emery or sandpaper), then burnishing the contacts.

If it is the centrifugal switch, I'm hoping it easy to remove and replace.
What are the chances of that happening?

If the contacts' connection has become high in resistance due to
pitting from arcing, the motor could fail to spin up in the way
you've described.
When these motors fail to spin up, a very likely cause is the start
capacitor.
Depending upon what type of tester was used, the results indicated
when testing AC capacitors may be inconclusive as to the quality of
the capacitor.
Testing the motor with a new AC capacitor is a better approach.

If a fault has developed within the start winding of the motor, the
motor will most likely have to be replaced.

I think the easiest and most telling test will be to hook up an ohm meter
between the two start windings and see if there is continuity, then go from
there.

Hi WB,

You're right about the two capacitors. However they are wired in parallel in
this situation. Since I am not the original service guy on the gate, perhaps
it's not supposed to be that way. Here is the wiring diagram that I drew
from tracing out the connections.
http://www.pbase.com/mrfixit/image/81687434

Thanks for your reply.
--
David Farber
David Farber's Service Center
L.A., CA

 

[Wild_Bill]

Hi David, I think I should've mentioned that my motor comments were related
to testing a motor that's been isolated from any controls, as in bench
testing.
Bench testing would be where the click of the centrifugal switch mechanism
would be very noticeable.

I dunno if the motor in the gate controller is a typical motor, or a
special-purpose motor built for this particular appliance (custom built for
the OEM/gate control company's specific requirements). If all of the
switching circuitry is separate from the motor, then it's probably a typical
motor.
Typical meaning that the internal switches in the motor would just be the
centrifugal switch, and a thermal protection device.

Testing the controls (wuuf! that's a lot of contacts) may be simplified by
placing test lamps at the motor connector, instead of the motor.
Light duty test lamps won't absolutely confirm that the main contactor for
the motor is capable of passing the motor's required current, but the lamps
should indicate that the basic open and close functions are taking place.
There are probably some devices (possibly a single device) that act as
travel limit switches for the gate arm/linkage.

So, I would suspect that if you place lamps where the motor would be, when
you select Open, the one lamp would be on until you give the controller the
limit signal (it's open, so stop).
Then if I understand, the controller delay will cause a pause before the
controller will auto-cycle to Close, so the other lamp should light until
you give the controller the limit signal (it's closed, so stop).

Starting these types of motors repeatedly is severe duty for the start
windings and the start capacitor(s). What I mean by repeatedly would be the
motor starting more than 6 or 8 times per hour. And since each opening is
actually starting the motor twice, using test lamps for testing may be a
good idea.
If you had some heavier loads (6 to 10A) to substitute the motor with, that
would be more of an actual test of the controller, as the motor will draw
some serious current very briefly each time it starts.

Typically, the centrifugal switch for the start winding is located in the
end bell of the motor opposite the output shaft end (usually the end where
the leads enter the motor).
The switch contacts are generally secured to the end bell of the motor.

Removing the end bell of a general purpose utility-type motor usually means
removing the nuts from four long screws that secure the end bells and center
(stator section) together, by running thru the case with screw heads at one
end, and nuts at the other.
It's always a good idea to mark the orientation of the end bells to the case
by making distinct marks at both ends of the case and the end bells, where
the end bells meet the case.

Maybe Bob Parker would know the specific differences, but I believe that the
characteristics of AC capacitors used in induction motors are significantly
different than electrolytic capacitors typically found in electronic
equipment.

Other signs to look for in this type of unit would be discolored terminals
on wiring connections, which generally always indicates high resistance
connections that have overheated.

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


"David Farber" <farberbear.unspam@aol.com> wrote in message
news:4a58d6b9$1$9366$bd467cd0@news.dslextreme.com...

Interesting point about the "click." I do here click(s?) when the gate
stops
moving. I had always thought the click was being caused by the mechanical
movement of the switching relays.


These types of motors aren't instantly reversible.
There is about a 30 second delay before the gate starts to automatically
close after reaching the fully open positioned. I don't think it is
possible
for the rotor to continue to turn if the gate has stopped unless there is
some intermediate transmission in the motor itself.


If it is the centrifugal switch, I'm hoping it easy to remove and replace.
What are the chances of that happening?


If a fault has developed within the start winding of the motor, the
motor will most likely have to be replaced.

I think the easiest and most telling test will be to hook up an ohm meter
between the two start windings and see if there is continuity, then go
from
there.



Hi WB,

You're right about the two capacitors. However they are wired in parallel
in
this situation. Since I am not the original service guy on the gate,
perhaps
it's not supposed to be that way. Here is the wiring diagram that I drew
from tracing out the connections.
http://www.pbase.com/mrfixit/image/81687434

Thanks for your reply.
--
David Farber
David Farber's Service Center
L.A., CA

 

[Jamie]

David Farber wrote:

I have an automatic gate which uses a GE 5KH36HN62T motor to open and close
the gate. The gate intermittently will not open. You can hear the motor buzz
and it will start moving if given a gentle push. The motor uses a capacitor
start circuit to get it going. The other fault with the motor is that
sometimes it turns in the wrong direction. This is my analysis of the
situation so correct me if I'm wrong. The fact that the motor buzzes and
will start turning with a gentle assist probably means there is a fault in
the start circuit. I tested the capacitors and they are ok. So I'm thinking
the internal motor start switch is sticking open. As far as the motor
occasionally turning the wrong direction, that too can be attributed to the
faulty start circuit because not only does the start circuit get the motor
going from a stopped position, it determines the direction that motor will
turn. If the load is light enough, the motor now may turn in either
direction if the start windings are not giving it its initial boost. Does
this make sense?

Yes
check the centrifugal switch.

 

[Jamie]

David Farber wrote:

Meat Plow wrote:

On Fri, 10 Jul 2009 14:54:38 -0700, "David Farber"
farberbear.unspam@aol.com>wrote:


I have an automatic gate which uses a GE 5KH36HN62T motor to open
and close the gate. The gate intermittently will not open. You can
hear the motor buzz and it will start moving if given a gentle push.
The motor uses a capacitor start circuit to get it going. The other
fault with the motor is that sometimes it turns in the wrong
direction. This is my analysis of the situation so correct me if I'm
wrong. The fact that the motor buzzes and will start turning with a
gentle assist probably means there is a fault in the start circuit.
I tested the capacitors and they are ok. So I'm thinking the
internal motor start switch is sticking open. As far as the motor
occasionally turning the wrong direction, that too can be attributed
to the faulty start circuit because not only does the start circuit
get the motor going from a stopped position, it determines the
direction that motor will turn. If the load is light enough, the
motor now may turn in either direction if the start windings are not
giving it its initial boost. Does this make sense?

Thanks for your reply.

How did you test the start cap? If it's flaky it's not going to
advance the phase to start the motor and could possibly start
backwords.


I tested the caps with my Bob Parker ESR meter. There are two 130uF 330V
capacitors in parallel. I checked them out of circuit to make sure. I'm
fairly certain I tested them for shorts because the ESR was very low. I'm
going to have another visit with the gate this afternoon and specifically
test out the motor starting circuit.
ESR meter isn't telling you the full story...

You need to know the Farad value..
ESR is not a factor here.

 

[David Farber]

"David Farber" <farberbear.unspam@aol.com> wrote in message
news:4a58d6b9$1$9366$bd467cd0@news.dslextreme.com...

Interesting point about the "click." I do here click(s?) when the
gate stops
moving. I had always thought the click was being caused by the
mechanical movement of the switching relays.


These types of motors aren't instantly reversible.
There is about a 30 second delay before the gate starts to
automatically close after reaching the fully open positioned. I
don't think it is possible
for the rotor to continue to turn if the gate has stopped unless
there is some intermediate transmission in the motor itself.


If it is the centrifugal switch, I'm hoping it easy to remove and
replace. What are the chances of that happening?


If a fault has developed within the start winding of the motor, the
motor will most likely have to be replaced.

I think the easiest and most telling test will be to hook up an ohm
meter between the two start windings and see if there is continuity,
then go from
there.



Hi WB,

You're right about the two capacitors. However they are wired in
parallel in
this situation. Since I am not the original service guy on the gate,
perhaps
it's not supposed to be that way. Here is the wiring diagram that I
drew from tracing out the connections.
http://www.pbase.com/mrfixit/image/81687434

Thanks for your reply.

Wild_Bill wrote:

Hi David, I think I should've mentioned that my motor comments were
related to testing a motor that's been isolated from any controls, as
in bench testing.
Bench testing would be where the click of the centrifugal switch
mechanism would be very noticeable.

I dunno if the motor in the gate controller is a typical motor, or a
special-purpose motor built for this particular appliance (custom
built for the OEM/gate control company's specific requirements). If
all of the switching circuitry is separate from the motor, then it's
probably a typical motor.
Typical meaning that the internal switches in the motor would just be
the centrifugal switch, and a thermal protection device.

Testing the controls (wuuf! that's a lot of contacts) may be
simplified by placing test lamps at the motor connector, instead of
the motor. Light duty test lamps won't absolutely confirm that the main
contactor for the motor is capable of passing the motor's required
current, but the lamps should indicate that the basic open and close
functions are taking place. There are probably some devices (possibly
a single device) that act as travel limit switches for the gate
arm/linkage.
So, I would suspect that if you place lamps where the motor would be,
when you select Open, the one lamp would be on until you give the
controller the limit signal (it's open, so stop).
Then if I understand, the controller delay will cause a pause before
the controller will auto-cycle to Close, so the other lamp should
light until you give the controller the limit signal (it's closed, so
stop).
Starting these types of motors repeatedly is severe duty for the start
windings and the start capacitor(s). What I mean by repeatedly would
be the motor starting more than 6 or 8 times per hour. And since each
opening is actually starting the motor twice, using test lamps for
testing may be a good idea.
If you had some heavier loads (6 to 10A) to substitute the motor
with, that would be more of an actual test of the controller, as the
motor will draw some serious current very briefly each time it starts.

Typically, the centrifugal switch for the start winding is located in
the end bell of the motor opposite the output shaft end (usually the
end where the leads enter the motor).
The switch contacts are generally secured to the end bell of the
motor.
Removing the end bell of a general purpose utility-type motor usually
means removing the nuts from four long screws that secure the end
bells and center (stator section) together, by running thru the case
with screw heads at one end, and nuts at the other.
It's always a good idea to mark the orientation of the end bells to
the case by making distinct marks at both ends of the case and the
end bells, where the end bells meet the case.

Maybe Bob Parker would know the specific differences, but I believe
that the characteristics of AC capacitors used in induction motors
are significantly different than electrolytic capacitors typically
found in electronic equipment.

Other signs to look for in this type of unit would be discolored
terminals on wiring connections, which generally always indicates
high resistance connections that have overheated.

I had another look at the motor and mechanism this afternoon. The motor
start ciruit measured open. Whether it's the centrifugal switch or it's the
start winding, it needs repair. As for right now, I'm going to call some
local motor repair shops next and see if it can be fixed. I like the idea
have having an experienced person look at it and not having to worry about
for another 30 years. The capacitors look ok physically. No swelling,
cracking, or discoloration. The relays show a tiny bit of wear but nothing
too bad.

Thanks for your reply.
--
David Farber
David Farber's Service Center
L.A., CA

 

[Meat Plow]

On Sat, 11 Jul 2009 11:13:51 -0700, "David Farber"
<farberbear.unspam@aol.com>wrote:

Meat Plow wrote:
On Fri, 10 Jul 2009 14:54:38 -0700, "David Farber"
farberbear.unspam@aol.com>wrote:

I have an automatic gate which uses a GE 5KH36HN62T motor to open
and close the gate. The gate intermittently will not open. You can
hear the motor buzz and it will start moving if given a gentle push.
The motor uses a capacitor start circuit to get it going. The other
fault with the motor is that sometimes it turns in the wrong
direction. This is my analysis of the situation so correct me if I'm
wrong. The fact that the motor buzzes and will start turning with a
gentle assist probably means there is a fault in the start circuit.
I tested the capacitors and they are ok. So I'm thinking the
internal motor start switch is sticking open. As far as the motor
occasionally turning the wrong direction, that too can be attributed
to the faulty start circuit because not only does the start circuit
get the motor going from a stopped position, it determines the
direction that motor will turn. If the load is light enough, the
motor now may turn in either direction if the start windings are not
giving it its initial boost. Does this make sense?

Thanks for your reply.

How did you test the start cap? If it's flaky it's not going to
advance the phase to start the motor and could possibly start
backwords.

I tested the caps with my Bob Parker ESR meter. There are two 130uF 330V
capacitors in parallel. I checked them out of circuit to make sure. I'm
fairly certain I tested them for shorts because the ESR was very low. I'm
going to have another visit with the gate this afternoon and specifically
test out the motor starting circuit.

Here is a schematic that I drew up a while back. Except for my head
scratching of what's energizing relay "B", I think the rest of the diagram
is accurate. It doesn't help that about 75% of the wires are all the same
color!

Schematic: http://www.pbase.com/mrfixit/image/81687434
For other pics of the electronics: http://www.pbase.com/mrfixit/gate

Thanks for your reply.

It's not rocket science. It's a GE fractional horsepower induction
motor. If the start cap is ok then the mechanical switching inside the
motor is bad. And I don't recall ever seeing the need to parallel two
130's together to get a 1/6 HP motor to start. Maybe one for run and
one for start but usually smaller value for the run cap. Find a
drawing for the motor.

 

[David Farber]

"Meat Plow" <meat@petitmorte.net> wrote in message
news:2v9ha9.43j.17.5@news.alt.net...

On Sat, 11 Jul 2009 11:13:51 -0700, "David Farber"
farberbear.unspam@aol.com>wrote:

Meat Plow wrote:
On Fri, 10 Jul 2009 14:54:38 -0700, "David Farber"
farberbear.unspam@aol.com>wrote:

I have an automatic gate which uses a GE 5KH36HN62T motor to open
and close the gate. The gate intermittently will not open. You can
hear the motor buzz and it will start moving if given a gentle push.
The motor uses a capacitor start circuit to get it going. The other
fault with the motor is that sometimes it turns in the wrong
direction. This is my analysis of the situation so correct me if I'm
wrong. The fact that the motor buzzes and will start turning with a
gentle assist probably means there is a fault in the start circuit.
I tested the capacitors and they are ok. So I'm thinking the
internal motor start switch is sticking open. As far as the motor
occasionally turning the wrong direction, that too can be attributed
to the faulty start circuit because not only does the start circuit
get the motor going from a stopped position, it determines the
direction that motor will turn. If the load is light enough, the
motor now may turn in either direction if the start windings are not
giving it its initial boost. Does this make sense?

Thanks for your reply.

How did you test the start cap? If it's flaky it's not going to
advance the phase to start the motor and could possibly start
backwords.

I tested the caps with my Bob Parker ESR meter. There are two 130uF 330V
capacitors in parallel. I checked them out of circuit to make sure. I'm
fairly certain I tested them for shorts because the ESR was very low. I'm
going to have another visit with the gate this afternoon and specifically
test out the motor starting circuit.

Here is a schematic that I drew up a while back. Except for my head
scratching of what's energizing relay "B", I think the rest of the diagram
is accurate. It doesn't help that about 75% of the wires are all the same
color!

Schematic: http://www.pbase.com/mrfixit/image/81687434
For other pics of the electronics: http://www.pbase.com/mrfixit/gate

Thanks for your reply.

It's not rocket science. It's a GE fractional horsepower induction
motor. If the start cap is ok then the mechanical switching inside the
motor is bad. And I don't recall ever seeing the need to parallel two
130's together to get a 1/6 HP motor to start. Maybe one for run and
one for start but usually smaller value for the run cap. Find a
drawing for the motor.

Here are some additional specs I found on the motor label:

1/3 hp

Von Weise Gear Co., St. Louis, Missouri
Model V00358AG10
6 (six!) rpm.

Time Rating: cont.

I still cannot find any info regarding what value capacitor should be
installed with this motor. The motor with pulley and case weighs 30 pounds.
I saw a hefty spring inside the casing via an air vent near the bottom.

Thanks for your reply.

--
David Farber
David Farber's Service Center
L.A., CA

 

[Meat Plow]

On Sun, 12 Jul 2009 17:39:48 -0700, "David Farber"
<farberbear.unspam@aol.com>wrote:

"Meat Plow" <meat@petitmorte.net> wrote in message
news:2v9ha9.43j.17.5@news.alt.net...
On Sat, 11 Jul 2009 11:13:51 -0700, "David Farber"
farberbear.unspam@aol.com>wrote:

Meat Plow wrote:
On Fri, 10 Jul 2009 14:54:38 -0700, "David Farber"
farberbear.unspam@aol.com>wrote:

I have an automatic gate which uses a GE 5KH36HN62T motor to open
and close the gate. The gate intermittently will not open. You can
hear the motor buzz and it will start moving if given a gentle push.
The motor uses a capacitor start circuit to get it going. The other
fault with the motor is that sometimes it turns in the wrong
direction. This is my analysis of the situation so correct me if I'm
wrong. The fact that the motor buzzes and will start turning with a
gentle assist probably means there is a fault in the start circuit.
I tested the capacitors and they are ok. So I'm thinking the
internal motor start switch is sticking open. As far as the motor
occasionally turning the wrong direction, that too can be attributed
to the faulty start circuit because not only does the start circuit
get the motor going from a stopped position, it determines the
direction that motor will turn. If the load is light enough, the
motor now may turn in either direction if the start windings are not
giving it its initial boost. Does this make sense?

Thanks for your reply.

How did you test the start cap? If it's flaky it's not going to
advance the phase to start the motor and could possibly start
backwords.

I tested the caps with my Bob Parker ESR meter. There are two 130uF 330V
capacitors in parallel. I checked them out of circuit to make sure. I'm
fairly certain I tested them for shorts because the ESR was very low. I'm
going to have another visit with the gate this afternoon and specifically
test out the motor starting circuit.

Here is a schematic that I drew up a while back. Except for my head
scratching of what's energizing relay "B", I think the rest of the diagram
is accurate. It doesn't help that about 75% of the wires are all the same
color!

Schematic: http://www.pbase.com/mrfixit/image/81687434
For other pics of the electronics: http://www.pbase.com/mrfixit/gate

Thanks for your reply.

It's not rocket science. It's a GE fractional horsepower induction
motor. If the start cap is ok then the mechanical switching inside the
motor is bad. And I don't recall ever seeing the need to parallel two
130's together to get a 1/6 HP motor to start. Maybe one for run and
one for start but usually smaller value for the run cap. Find a
drawing for the motor.

Here are some additional specs I found on the motor label:

1/3 hp

Von Weise Gear Co., St. Louis, Missouri
Model V00358AG10
6 (six!) rpm.

Von Weise gear motor.

http://www.vonweise.com/
http://www.vonweise.com/address.html

Von Weise Gear Company
Industrial Park
Saint Clair, MO 63077

Tel. 636.629.1010


They should have info on their unit.

Time Rating: cont.

I still cannot find any info regarding what value capacitor should be
installed with this motor. The motor with pulley and case weighs 30 pounds.
I saw a hefty spring inside the casing via an air vent near the bottom.

I've repaired several Baldor 10/15 horse / 230 volt single phase
repulsion/induction motors. Repulsion motor on start for high torque
commutator is shunted at speed and then runs as repulsion motor. No
caps needed. When I say repair I mean assembled rebuilt parts and
dressed the comm. This motor weighs 370 lbs.

You are going to have to find someone familiar with the gearmotor call
Von Weise.

 

[Wild_Bill]

I was wondering earlier, if the motor was a gearhead motor. With an output
of 6 RPM, there wouldn't definitely be a need for high starting torque for
the motor shaft, since the geartrain provides output shaft torque.

So, the capacitors that were found may not be the original ones, and are not
likely to be for a 1/6 HP motor.
The motor shop where I get parts told me that a general guideline for start
capacitor (value) sizing is 500uF for 1 HP, for capacitor start split-phase
motors.
The capacitor value you found would be adequate for a capacitor start
split-phase motor of 3/4 HP to 1 HP.
Anything is possible with used equipment, and if the capacitor had failed in
the past, someone may have confused the resistors-in-parallel rule, with
capacitors in parallel.

Since the gear reduction unit provides a considerable amount of torque, it's
possible that the motor may be a PSC permanent split capacitor type, and not
a capaitor start split-phase motor.

The capacitor value would still be wrong for a PSC motor that size. PSC
motors are often used with gear reduction boxes to provide low RPM outputs,
but the capacitors used are very low values, as in single or double-digit
values, not 100+uF.

PSC motors are fairly simple, in that the stator is made up of two identical
windings in series, with the 3 terminals arranged like a center-tapped
transformer winding.
The connection of one of the capacitor's leads is changed for CW or CCW
rotation.

Commercial application PSC motors are very reliable, they often have ball
bearings for the motor shaft, and nearly always have internal thermal
protection, and they are commonly designed with impedance protection.

The PSC types don't have centrifugal switches, and the spring you saw thru
the vent is likely to be part of the mechanism for a centrifugal switch.

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


"David Farber" <farberbear.unspam@aol.com> wrote in message
news:4a5a829e$0$8678$bd467cd0@news.dslextreme.com...

Here are some additional specs I found on the motor label:

1/3 hp

Von Weise Gear Co., St. Louis, Missouri
Model V00358AG10
6 (six!) rpm.

Time Rating: cont.

I still cannot find any info regarding what value capacitor should be
installed with this motor. The motor with pulley and case weighs 30
pounds.
I saw a hefty spring inside the casing via an air vent near the bottom.

Thanks for your reply.

--
David Farber
David Farber's Service Center
L.A., CA

 

[David Farber]

"David Farber" <farberbear.unspam@aol.com> wrote in message
news:4a5a829e$0$8678$bd467cd0@news.dslextreme.com...

Here are some additional specs I found on the motor label:

1/3 hp

Von Weise Gear Co., St. Louis, Missouri
Model V00358AG10
6 (six!) rpm.

Time Rating: cont.

I still cannot find any info regarding what value capacitor should be
installed with this motor. The motor with pulley and case weighs 30
pounds.
I saw a hefty spring inside the casing via an air vent near the
bottom.

Thanks for your reply.

Wild_Bill wrote:

I was wondering earlier, if the motor was a gearhead motor. With an
output of 6 RPM, there wouldn't definitely be a need for high
starting torque for the motor shaft, since the geartrain provides
output shaft torque.

So, the capacitors that were found may not be the original ones, and
are not likely to be for a 1/6 HP motor.
The motor shop where I get parts told me that a general guideline for
start capacitor (value) sizing is 500uF for 1 HP, for capacitor start
split-phase motors.
The capacitor value you found would be adequate for a capacitor start
split-phase motor of 3/4 HP to 1 HP.
Anything is possible with used equipment, and if the capacitor had
failed in the past, someone may have confused the
resistors-in-parallel rule, with capacitors in parallel.

Since the gear reduction unit provides a considerable amount of
torque, it's possible that the motor may be a PSC permanent split
capacitor type, and not a capaitor start split-phase motor.

The capacitor value would still be wrong for a PSC motor that size.
PSC motors are often used with gear reduction boxes to provide low
RPM outputs, but the capacitors used are very low values, as in
single or double-digit values, not 100+uF.

PSC motors are fairly simple, in that the stator is made up of two
identical windings in series, with the 3 terminals arranged like a
center-tapped transformer winding.
The connection of one of the capacitor's leads is changed for CW or
CCW rotation.

Commercial application PSC motors are very reliable, they often have
ball bearings for the motor shaft, and nearly always have internal
thermal protection, and they are commonly designed with impedance
protection.

The PSC types don't have centrifugal switches, and the spring you saw
thru the vent is likely to be part of the mechanism for a centrifugal
switch.


Just to update what I found out in the past few days: The label on the motor

says 1/3 hp. I called some repair shops and asked if they knew about the
start capacitance value. One tech told me that the GE 5KH series was a split
phase motor and did not require any start capacitor. I finally found a local
guy who was able to come to my shop and call me back with an estimate. He
said the aluminum start windings were bad and that he would replace both the
start and run windings with copper wires. As to the question of starting
capacitance, he said adding a capacitor wouldn't hurt especially if it was
running that way for a long time. I'll be getting the repaired motor back
tomorrow and hopefully it will be as good as new.

Thanks for your reply.
--
David Farber
David Farber's Service Center
L.A., CA

 

[Wild_Bill]

I'm glad you found a solution, David. From what I've been hearing in recent
years, shops that are interested in repairing small motors are becoming
scarce.

I realized that I'd mis-stated the HP rating you stated from the motor label
after the reply was sent. Still, that value of capacitance is excessively
high for a small motor.

The guy that said a split-phase motor doesn't require a start capacitor is
correct, although when S-P motors are manufactured with a start capacitor,
they're capable of being used in applications that require higher starting
torques, hence the CS,S-P naming.
Many heavy duty motor applications, such as industrial-duty air compressors
require motors with both start and run capacitors.. CS,CR,S-P type.

Because of the high gear ratio to attain the 6 RPM output, the starting
torque requirement wouldn't be very high. The ratio is over 250:1 for a 1700
RPM motor.

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


"David Farber" <farberbear.unspam@aol.com> wrote in message
news:O788m.51973$9P.42991@newsfe08.iad...

Just to update what I found out in the past few days: The label on the
motor
says 1/3 hp. I called some repair shops and asked if they knew about the
start capacitance value. One tech told me that the GE 5KH series was a
split
phase motor and did not require any start capacitor. I finally found a
local
guy who was able to come to my shop and call me back with an estimate. He
said the aluminum start windings were bad and that he would replace both
the
start and run windings with copper wires. As to the question of starting
capacitance, he said adding a capacitor wouldn't hurt especially if it was
running that way for a long time. I'll be getting the repaired motor back
tomorrow and hopefully it will be as good as new.

Thanks for your reply.
--
David Farber
David Farber's Service Center
L.A., CA

 

[mike]

Hey Wild Bill,

Elsewhere in this thread you mention adding a start capacitor to a
split phase motor, I'm wondering how one goes about gaining access to
the proper wires to hook it up, that is, is it usually straight
forward and easy to ID the proper hookup points, are the leads you
need to hook into usually long enough, or do you have to go digging
into the windings and add some wire and such?

Thanks,
Mike

Wild_Bill wrote:

I'm glad you found a solution, David. From what I've been hearing in recent
years, shops that are interested in repairing small motors are becoming
scarce.

I realized that I'd mis-stated the HP rating you stated from the motor label
after the reply was sent. Still, that value of capacitance is excessively
high for a small motor.

The guy that said a split-phase motor doesn't require a start capacitor is
correct, although when S-P motors are manufactured with a start capacitor,
they're capable of being used in applications that require higher starting
torques, hence the CS,S-P naming.
Many heavy duty motor applications, such as industrial-duty air compressors
require motors with both start and run capacitors.. CS,CR,S-P type.

Because of the high gear ratio to attain the 6 RPM output, the starting
torque requirement wouldn't be very high. The ratio is over 250:1 for a 1700
RPM motor.

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


"David Farber" <farberbear.unspam@aol.com> wrote in message
news:O788m.51973$9P.42991@newsfe08.iad...

Just to update what I found out in the past few days: The label on the
motor
says 1/3 hp. I called some repair shops and asked if they knew about the
start capacitance value. One tech told me that the GE 5KH series was a
split
phase motor and did not require any start capacitor. I finally found a
local
guy who was able to come to my shop and call me back with an estimate. He
said the aluminum start windings were bad and that he would replace both
the
start and run windings with copper wires. As to the question of starting
capacitance, he said adding a capacitor wouldn't hurt especially if it was
running that way for a long time. I'll be getting the repaired motor back
tomorrow and hopefully it will be as good as new.

Thanks for your reply.
--
David Farber
David Farber's Service Center
L.A., CA

 

[Wild_Bill]

In the typical utility type split-phase motor, the 120VAC line lead would go
directly to the centrifugal switch. The centrifugal switch is in series with
the start winding.
So, the terminals are generally available at the terminal board, although it
may be necessary to access the connections by removing the end bell from the
motor.
This usually makes it much easier to see/confirm the actual connections, and
check them with an ohm meter.
The capacitor can be prepared for connection by adding suitable leads to the
terminals, which will allow the connections to be made inside the motor's
case.

If the connection points are unclear, a motor book or the manufacturer's
wiring diagram may be helpful in determining the correct connection points.
Seek the help of a person that's qualified and experienced with motor wiring
if any of the comments mentioned here are unclear.

A suitably sized (value) AC capacitor with the properly rated working
voltage can be added in series with the AC line terminal and centrifugal
switch connector, which may just be quick connect, push-on terminals or
leads attached to screw posts with nuts.
Most fractional HP split-phase motors have these types of terminals, if
other types of connections are made, one would need to add some connections
that are properly insulated and isolated from rotating parts of the rotor.

Since the motor wasn't originally equipped with a starting capacitor, the
capacitor will need to be securely mounted to the motor case or near the
motor, with the terminal connections insulated.
An electrical workbox makes a good enlosure to house an external capacitor
in.

Thermal protection feature:
Fractional HP motors generally have self-resetting thermal protection
devices buried in the motor's windings, although larger output motors may
have manually resettable thermal protection switches which are externally
accessible, usually a red button marked Reset.
Thermal protection will help prevent damage to the motor caused from
overheating, from conditions such as reduced/blocked air flow or load
increase on the motor, but may not offer any protection in the event of a
jam or stall that takes place quickly.

Current protection devices can prevent motor damage by interrupting the
input power connections when over-current conditions take place.

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


"mike" <mlightner@survivormail.com> wrote in message
news:34106911-f39a-41d4-a3ba-ae4b6915dcda@m7g2000prd.googlegroups.com...

Hey Wild Bill,

Elsewhere in this thread you mention adding a start capacitor to a
split phase motor, I'm wondering how one goes about gaining access to
the proper wires to hook it up, that is, is it usually straight
forward and easy to ID the proper hookup points, are the leads you
need to hook into usually long enough, or do you have to go digging
into the windings and add some wire and such?

Thanks,
Mike

Wild_Bill wrote:
I'm glad you found a solution, David. From what I've been hearing in
recent
years, shops that are interested in repairing small motors are becoming
scarce.

I realized that I'd mis-stated the HP rating you stated from the motor
label
after the reply was sent. Still, that value of capacitance is excessively
high for a small motor.

The guy that said a split-phase motor doesn't require a start capacitor
is
correct, although when S-P motors are manufactured with a start
capacitor,
they're capable of being used in applications that require higher
starting
torques, hence the CS,S-P naming.
Many heavy duty motor applications, such as industrial-duty air
compressors
require motors with both start and run capacitors.. CS,CR,S-P type.

Because of the high gear ratio to attain the 6 RPM output, the starting
torque requirement wouldn't be very high. The ratio is over 250:1 for a
1700
RPM motor.

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