Armature burning in AC motor

K

klem kedidelhopper

Guest
We have a motor that came out of a Rigid wood planer that had started
to burn at the commutator.
We took the armature out and noted that it was pretty blackened but
not noticeably worn or out of round. We buffed it up with a soft wire
wheel, cleaned between the segments, and except for a slight bit of
"raggedness" between the segments it shows little wear and it cleaned
up nicely. There were no shorts to ground and it looked good on the
growler as well. This motor was previously apparently operated with
worn brushes and I thought that this would be the extent of it when we
replaced them. The new brushes are making good contact on the segments
now, however severe burning is still taking place more so at one brush
than the other. We took it to a motor shop and they can't figure it
out either. The field does not look burned and checks good too. The
motor operates on 120V 60Hz. Does anyone have any ideas? Thanks, Lenny
 
klem kedidelhopper <captainvideo462009@gmail.com> wrote in message
news:2a12d90f-ec2b-4ba4-a72b-03aaaa9f9284@f5g2000vby.googlegroups.com...
We have a motor that came out of a Rigid wood planer that had started
to burn at the commutator.
We took the armature out and noted that it was pretty blackened but
not noticeably worn or out of round. We buffed it up with a soft wire
wheel, cleaned between the segments, and except for a slight bit of
"raggedness" between the segments it shows little wear and it cleaned
up nicely. There were no shorts to ground and it looked good on the
growler as well. This motor was previously apparently operated with
worn brushes and I thought that this would be the extent of it when we
replaced them. The new brushes are making good contact on the segments
now, however severe burning is still taking place more so at one brush
than the other. We took it to a motor shop and they can't figure it
out either. The field does not look burned and checks good too. The
motor operates on 120V 60Hz. Does anyone have any ideas? Thanks, Lenny
Click to expand...

intermittant wiring short when the motor is spinning ?
 
On Apr 19, 3:26 am, "N_Cook" <dive...@tcp.co.uk> wrote:
klem kedidelhopper <captainvideo462...@gmail.com> wrote in message

news:2a12d90f-ec2b-4ba4-a72b-03aaaa9f9284@f5g2000vby.googlegroups.com...

We have a motor that came out of a Rigid wood planer that had started
to burn at the commutator.
We took the armature out and noted that it was pretty blackened but
not noticeably worn or out of round. We buffed it up with a soft wire
wheel, cleaned between the segments,  and  except for a slight bit of
"raggedness" between the segments it shows little wear and it cleaned
up nicely. There were no shorts to ground and it looked good on the
growler as well. This motor was previously apparently operated with
worn brushes and I thought that this would be the extent of it when we
replaced them. The new brushes are making good contact on the segments
now, however severe burning is still taking place more so at one brush
than the other. We took it to a motor shop and they can't figure it
out either. The field does not look burned and checks good too. The
motor operates on 120V 60Hz.  Does anyone have any ideas? Thanks, Lenny

intermittant wiring short when the motor is spinning ?
At this point I'm at a loss so I suppose that anything is possible.
Click to expand...
Lenny
 
klem kedidelhopper Inscribed thus:

We have a motor that came out of a Rigid wood planer that had started
to burn at the commutator.
We took the armature out and noted that it was pretty blackened but
not noticeably worn or out of round. We buffed it up with a soft wire
wheel, cleaned between the segments, and except for a slight bit of
"raggedness" between the segments it shows little wear and it cleaned
up nicely. There were no shorts to ground and it looked good on the
growler as well. This motor was previously apparently operated with
worn brushes and I thought that this would be the extent of it when we
replaced them. The new brushes are making good contact on the segments
now, however severe burning is still taking place more so at one brush
than the other. We took it to a motor shop and they can't figure it
out either. The field does not look burned and checks good too. The
motor operates on 120V 60Hz. Does anyone have any ideas? Thanks,
Lenny
Click to expand...
Check interference suppression capacitors for o/c.

--
Best Regards:
Baron.
 
klem kedidelhopper wrote:

We have a motor that came out of a Rigid wood planer that had started
to burn at the commutator.
We took the armature out and noted that it was pretty blackened but
not noticeably worn or out of round. We buffed it up with a soft wire
wheel, cleaned between the segments, and except for a slight bit of
"raggedness" between the segments it shows little wear and it cleaned
up nicely. There were no shorts to ground and it looked good on the
growler as well. This motor was previously apparently operated with
worn brushes and I thought that this would be the extent of it when we
replaced them. The new brushes are making good contact on the segments
now, however severe burning is still taking place more so at one brush
than the other. We took it to a motor shop and they can't figure it
out either. The field does not look burned and checks good too. The
motor operates on 120V 60Hz. Does anyone have any ideas? Thanks, Lenny
Click to expand...
If only a couple commutator slugs are burned, that is a sure sign of a
shorted turn in the associated armature winding. If there are no particular
slugs that are burned, then I'm thinking the field winding has a shorted
turn.
What happens in this case is the field is now out of phase with the AC
line and armature current, so the armature sees a lot higher line voltage
at the wrong part of the AC cycle. Does it seem to run at the wrong
speed, take a different amount of time to spin up, etc?

(I'm assuming this is a universal motor.)

Jon
 
klem kedidelhopper wrote:

We have a motor that came out of a Rigid wood planer that had started
to burn at the commutator.
We took the armature out and noted that it was pretty blackened but
not noticeably worn or out of round. We buffed it up with a soft wire
wheel, cleaned between the segments, and except for a slight bit of
"raggedness" between the segments it shows little wear and it cleaned
up nicely. There were no shorts to ground and it looked good on the
growler as well. This motor was previously apparently operated with
worn brushes and I thought that this would be the extent of it when we
replaced them. The new brushes are making good contact on the segments
now, however severe burning is still taking place more so at one brush
than the other. We took it to a motor shop and they can't figure it
out either. The field does not look burned and checks good too. The
motor operates on 120V 60Hz. Does anyone have any ideas? Thanks, Lenny
Click to expand...
You need to use a DCR bridge or Kelvin bridge meter and slowly rotate
the rotor looking for significant differences in turn windings on the
poles.

Also, check brush alignment.

Jamie
 
Jamie wrote:
klem kedidelhopper wrote:

We have a motor that came out of a Rigid wood planer that had started
to burn at the commutator.
We took the armature out and noted that it was pretty blackened but
not noticeably worn or out of round. We buffed it up with a soft wire
wheel, cleaned between the segments, and except for a slight bit of
"raggedness" between the segments it shows little wear and it cleaned
up nicely. There were no shorts to ground and it looked good on the
growler as well. This motor was previously apparently operated with
worn brushes and I thought that this would be the extent of it when
we replaced them. The new brushes are making good contact on the
segments now, however severe burning is still taking place more so
at one brush than the other. We took it to a motor shop and they
can't figure it out either. The field does not look burned and
checks good too. The motor operates on 120V 60Hz. Does anyone have
any ideas? Thanks, Lenny

You need to use a DCR bridge or Kelvin bridge meter and slowly rotate
the rotor looking for significant differences in turn windings on the
poles.

Also, check brush alignment.

Jamie
Click to expand...
Does the planer have a dynamic braking feature? If so, I'll bet that's
what's causing the burning. I have a Ryobi cordless drill that has dynamic
braking, and after running the drill, when the trigger is released, there is
some major sparking at the commutator & brushes.
I haven't seen anybody offer a reasonable fix that can be proven to work and
not disrupt something else in the circuit. I know that arc suppressors
and/or Tranzorbs might be viable fixes, but I haven't seen anything
definitive on it. A pointer to more info on arc suppression for dynamically
braked motors would be appreciated. Google turns up lots of patent
applications, but I haven't found anything that substantiates the claims.
--
Dave M
A woman has the last word in any argument. Anything a man says after
that is the beginning of a new argument.
 
klem kedidelhopper wrote:

On Apr 20, 6:12 am, "Dave M" <dgminala4...@mediacombb.net> wrote:

Jamie wrote:

klem kedidelhopper wrote:

We have a motor that came out of a Rigid wood planer that had started
to burn at the commutator.
We took the armature out and noted that it was pretty blackened but
not noticeably worn or out of round. We buffed it up with a soft wire
wheel, cleaned between the segments, and except for a slight bit of
"raggedness" between the segments it shows little wear and it cleaned
up nicely. There were no shorts to ground and it looked good on the
growler as well. This motor was previously apparently operated with
worn brushes and I thought that this would be the extent of it when
we replaced them. The new brushes are making good contact on the
segments now, however severe burning is still taking place more so
at one brush than the other. We took it to a motor shop and they
can't figure it out either. The field does not look burned and
checks good too. The motor operates on 120V 60Hz. Does anyone have
any ideas? Thanks, Lenny

You need to use a DCR bridge or Kelvin bridge meter and slowly rotate
the rotor looking for significant differences in turn windings on the
poles.

Also, check brush alignment.

Jamie

Does the planer have a dynamic braking feature? If so, I'll bet that's
what's causing the burning. I have a Ryobi cordless drill that has dynamic
braking, and after running the drill, when the trigger is released, there is
some major sparking at the commutator & brushes.
I haven't seen anybody offer a reasonable fix that can be proven to work and
not disrupt something else in the circuit. I know that arc suppressors
and/or Tranzorbs might be viable fixes, but I haven't seen anything
definitive on it. A pointer to more info on arc suppression for dynamically
braked motors would be appreciated. Google turns up lots of patent
applications, but I haven't found anything that substantiates the claims.
--
Dave M
A woman has the last word in any argument. Anything a man says after
that is the beginning of a new argument.


The motor is out of the unit. There are no brakes involved. Lenny
If you have a universal motor (most likely), then I suspect a problem
Click to expand...
in the field.

If you inspect the motor's wiring, you should see one of the leads
going to the field and back out and then to a brush, or, the motor
allows the wires out side for you to wire it this way.

It's common for these types of motors to short in the field there by,
heating up faster than it should and sparking a lot on the brushes.
Also, you may notice lack of power.

The field could look and check good on a mega but still have shorted
turns in it. You need to know the correct ohms to determine that.

Jamie
 
On Apr 20, 6:12 am, "Dave M" <dgminala4...@mediacombb.net> wrote:
Jamie wrote:
klem kedidelhopper wrote:

We have a motor that came out of a Rigid wood planer that had started
to burn at the commutator.
We took the armature out and noted that it was pretty blackened but
not noticeably worn or out of round. We buffed it up with a soft wire
wheel, cleaned between the segments,  and  except for a slight bit of
"raggedness" between the segments it shows little wear and it cleaned
up nicely. There were no shorts to ground and it looked good on the
growler as well. This motor was previously apparently operated with
worn brushes and I thought that this would be the extent of it when
we replaced them. The new brushes are making good contact on the
segments now, however severe burning is still taking place more so
at one brush than the other. We took it to a motor shop and they
can't figure it out either. The field does not look burned and
checks good too. The motor operates on 120V 60Hz.  Does anyone have
any ideas? Thanks, Lenny

 You need to use a DCR bridge or Kelvin bridge meter and slowly rotate
the rotor looking for significant differences in turn windings on the
poles.

 Also, check brush alignment.

 Jamie

Does the planer have a dynamic braking feature?  If so, I'll bet that's
what's causing the burning.  I have a Ryobi cordless drill that has dynamic
braking, and after running the drill, when the trigger is released, there is
some major sparking at the commutator & brushes.
I haven't seen anybody offer a reasonable fix that can be proven to work and
not disrupt something else in the circuit.  I know that arc suppressors
and/or Tranzorbs might be viable fixes, but I haven't seen anything
definitive on it.  A pointer to more info on arc suppression for dynamically
braked motors would be appreciated.  Google turns up lots of patent
applications, but I haven't found anything that substantiates the claims.
--
Dave M
A woman has the last word in any argument. Anything a man says after
that is the beginning of a new argument.
Click to expand...
The motor is out of the unit. There are no brakes involved. Lenny
 
On Apr 20, 10:24 pm, Jamie
<jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:
klem kedidelhopper wrote:
On Apr 20, 6:12 am, "Dave M" <dgminala4...@mediacombb.net> wrote:

Jamie wrote:

klem kedidelhopper wrote:

We have a motor that came out of a Rigid wood planer that had started
to burn at the commutator.
We took the armature out and noted that it was pretty blackened but
not noticeably worn or out of round. We buffed it up with a soft wire
wheel, cleaned between the segments,  and  except for a slight bit of
"raggedness" between the segments it shows little wear and it cleaned
up nicely. There were no shorts to ground and it looked good on the
growler as well. This motor was previously apparently operated with
worn brushes and I thought that this would be the extent of it when
we replaced them. The new brushes are making good contact on the
segments now, however severe burning is still taking place more so
at one brush than the other. We took it to a motor shop and they
can't figure it out either. The field does not look burned and
checks good too. The motor operates on 120V 60Hz.  Does anyone have
any ideas? Thanks, Lenny

You need to use a DCR bridge or Kelvin bridge meter and slowly rotate
the rotor looking for significant differences in turn windings on the
poles.

Also, check brush alignment.

Jamie

Does the planer have a dynamic braking feature?  If so, I'll bet that's
what's causing the burning.  I have a Ryobi cordless drill that has dynamic
braking, and after running the drill, when the trigger is released, there is
some major sparking at the commutator & brushes.
I haven't seen anybody offer a reasonable fix that can be proven to work and
not disrupt something else in the circuit.  I know that arc suppressors
and/or Tranzorbs might be viable fixes, but I haven't seen anything
definitive on it.  A pointer to more info on arc suppression for dynamically
braked motors would be appreciated.  Google turns up lots of patent
applications, but I haven't found anything that substantiates the claims.
--
Dave M
A woman has the last word in any argument. Anything a man says after
that is the beginning of a new argument.

The motor is out of the unit. There are no brakes involved. Lenny

If you have a universal motor (most likely), then I suspect a problem
in the field.

   If you inspect the motor's wiring, you should see one of the leads
going to the field and back out and then to a brush, or, the motor
allows the wires out side for you to wire it this way.

   It's common for these types of motors to short in the field there by,
heating up faster than it should and sparking a lot on the brushes.
Also, you may notice lack of power.

   The field could look and check good on a mega but still have shorted
turns in it. You need to know the correct ohms to determine that.

Jamie
Click to expand...
I would never be able to determine correct resistance. How about the
run current? If the brushes are sparking should I expect to see a
substantial increase in line current? On second thought the run
current would probably vary depending on load, so I don't really know
how much information I could get from that either. I really don't want
to give up on this thing but a new motor is more than 2/3 the cost of
replacement so it's starting to look that way. I just wish that there
was a definitive way to determine exactly what the problem is. Lenny
 
klem kedidelhopper wrote:

On Apr 20, 10:24 pm, Jamie
jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:

klem kedidelhopper wrote:

On Apr 20, 6:12 am, "Dave M" <dgminala4...@mediacombb.net> wrote:

Jamie wrote:

klem kedidelhopper wrote:

We have a motor that came out of a Rigid wood planer that had started
to burn at the commutator.
We took the armature out and noted that it was pretty blackened but
not noticeably worn or out of round. We buffed it up with a soft wire
wheel, cleaned between the segments, and except for a slight bit of
"raggedness" between the segments it shows little wear and it cleaned
up nicely. There were no shorts to ground and it looked good on the
growler as well. This motor was previously apparently operated with
worn brushes and I thought that this would be the extent of it when
we replaced them. The new brushes are making good contact on the
segments now, however severe burning is still taking place more so
at one brush than the other. We took it to a motor shop and they
can't figure it out either. The field does not look burned and
checks good too. The motor operates on 120V 60Hz. Does anyone have
any ideas? Thanks, Lenny

You need to use a DCR bridge or Kelvin bridge meter and slowly rotate
the rotor looking for significant differences in turn windings on the
poles.

Also, check brush alignment.

Jamie

Does the planer have a dynamic braking feature? If so, I'll bet that's
what's causing the burning. I have a Ryobi cordless drill that has dynamic
braking, and after running the drill, when the trigger is released, there is
some major sparking at the commutator & brushes.
I haven't seen anybody offer a reasonable fix that can be proven to work and
not disrupt something else in the circuit. I know that arc suppressors
and/or Tranzorbs might be viable fixes, but I haven't seen anything
definitive on it. A pointer to more info on arc suppression for dynamically
braked motors would be appreciated. Google turns up lots of patent
applications, but I haven't found anything that substantiates the claims.
--
Dave M
A woman has the last word in any argument. Anything a man says after
that is the beginning of a new argument.

The motor is out of the unit. There are no brakes involved. Lenny

If you have a universal motor (most likely), then I suspect a problem
in the field.

If you inspect the motor's wiring, you should see one of the leads
going to the field and back out and then to a brush, or, the motor
allows the wires out side for you to wire it this way.

It's common for these types of motors to short in the field there by,
heating up faster than it should and sparking a lot on the brushes.
Also, you may notice lack of power.

The field could look and check good on a mega but still have shorted
turns in it. You need to know the correct ohms to determine that.

Jamie


I would never be able to determine correct resistance. How about the
run current? If the brushes are sparking should I expect to see a
substantial increase in line current? On second thought the run
current would probably vary depending on load, so I don't really know
how much information I could get from that either. I really don't want
to give up on this thing but a new motor is more than 2/3 the cost of
replacement so it's starting to look that way. I just wish that there
was a definitive way to determine exactly what the problem is. Lenny
a lot of those motors spark anyway. That is the nature of them. They
Click to expand...
don't last very long! that is, the brushes don't last long in them.

When I say spark as in normal, I am only talking about a slight visual
spark on the corners. You shouldn't be seeing blacken sparks with in a
couple of run times though.

How good is the bearings in this motor?

Jamie
 
klem kedidelhopper wrote:

On Apr 22, 1:26 pm, Jamie
jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:

klem kedidelhopper wrote:

On Apr 20, 10:24 pm, Jamie
jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:

klem kedidelhopper wrote:

On Apr 20, 6:12 am, "Dave M" <dgminala4...@mediacombb.net> wrote:

Jamie wrote:

klem kedidelhopper wrote:

We have a motor that came out of a Rigid wood planer that had started
to burn at the commutator.
We took the armature out and noted that it was pretty blackened but
not noticeably worn or out of round. We buffed it up with a soft wire
wheel, cleaned between the segments, and except for a slight bit of
"raggedness" between the segments it shows little wear and it cleaned
up nicely. There were no shorts to ground and it looked good on the
growler as well. This motor was previously apparently operated with
worn brushes and I thought that this would be the extent of it when
we replaced them. The new brushes are making good contact on the
segments now, however severe burning is still taking place more so
at one brush than the other. We took it to a motor shop and they
can't figure it out either. The field does not look burned and
checks good too. The motor operates on 120V 60Hz. Does anyone have
any ideas? Thanks, Lenny

You need to use a DCR bridge or Kelvin bridge meter and slowly rotate
the rotor looking for significant differences in turn windings on the
poles.

Also, check brush alignment.

Jamie

Does the planer have a dynamic braking feature? If so, I'll bet that's
what's causing the burning. I have a Ryobi cordless drill that has dynamic
braking, and after running the drill, when the trigger is released, there is
some major sparking at the commutator & brushes.
I haven't seen anybody offer a reasonable fix that can be proven to work and
not disrupt something else in the circuit. I know that arc suppressors
and/or Tranzorbs might be viable fixes, but I haven't seen anything
definitive on it. A pointer to more info on arc suppression for dynamically
braked motors would be appreciated. Google turns up lots of patent
applications, but I haven't found anything that substantiates the claims.
--
Dave M
A woman has the last word in any argument. Anything a man says after
that is the beginning of a new argument.

The motor is out of the unit. There are no brakes involved. Lenny

If you have a universal motor (most likely), then I suspect a problem
in the field.

If you inspect the motor's wiring, you should see one of the leads
going to the field and back out and then to a brush, or, the motor
allows the wires out side for you to wire it this way.

It's common for these types of motors to short in the field there by,
heating up faster than it should and sparking a lot on the brushes.
Also, you may notice lack of power.

The field could look and check good on a mega but still have shorted
turns in it. You need to know the correct ohms to determine that.

Jamie

I would never be able to determine correct resistance. How about the
run current? If the brushes are sparking should I expect to see a
substantial increase in line current? On second thought the run
current would probably vary depending on load, so I don't really know
how much information I could get from that either. I really don't want
to give up on this thing but a new motor is more than 2/3 the cost of
replacement so it's starting to look that way. I just wish that there
was a definitive way to determine exactly what the problem is. Lenny

a lot of those motors spark anyway. That is the nature of them. They
don't last very long! that is, the brushes don't last long in them.

When I say spark as in normal, I am only talking about a slight visual
spark on the corners. You shouldn't be seeing blacken sparks with in a
couple of run times though.

How good is the bearings in this motor?

Jamie


The bearings are fine, and as far as the sparking goes, I know what
you mean about a "slight" spark at the brush contact points. I've seen
that before. This however is like a a white hot spark mostly at one
brush only which is strange, and quite large too. You can even hear it
burning over the motor noise. Lenny
Click to expand...
Inspect the leads going in, if the arching brush is the one that gets
connected to the field inside, you have a short in the field. Could be
to case. This assumes that you have a 2 wire motor of course. I wonder
what would happen if you removed the ground wire from the motor and make
sure the case does not come in contact with ground? You could also place
a DMM between the case and ground to test for leakage when operating.

jamie
 
On Apr 22, 1:26 pm, Jamie
<jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:
klem kedidelhopper wrote:
On Apr 20, 10:24 pm, Jamie
jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:

klem kedidelhopper wrote:

On Apr 20, 6:12 am, "Dave M" <dgminala4...@mediacombb.net> wrote:

Jamie wrote:

klem kedidelhopper wrote:

We have a motor that came out of a Rigid wood planer that had started
to burn at the commutator.
We took the armature out and noted that it was pretty blackened but
not noticeably worn or out of round. We buffed it up with a soft wire
wheel, cleaned between the segments,  and  except for a slight bit of
"raggedness" between the segments it shows little wear and it cleaned
up nicely. There were no shorts to ground and it looked good on the
growler as well. This motor was previously apparently operated with
worn brushes and I thought that this would be the extent of it when
we replaced them. The new brushes are making good contact on the
segments now, however severe burning is still taking place more so
at one brush than the other. We took it to a motor shop and they
can't figure it out either. The field does not look burned and
checks good too. The motor operates on 120V 60Hz.  Does anyone have
any ideas? Thanks, Lenny

You need to use a DCR bridge or Kelvin bridge meter and slowly rotate
the rotor looking for significant differences in turn windings on the
poles.

Also, check brush alignment.

Jamie

Does the planer have a dynamic braking feature?  If so, I'll bet that's
what's causing the burning.  I have a Ryobi cordless drill that has dynamic
braking, and after running the drill, when the trigger is released, there is
some major sparking at the commutator & brushes.
I haven't seen anybody offer a reasonable fix that can be proven to work and
not disrupt something else in the circuit.  I know that arc suppressors
and/or Tranzorbs might be viable fixes, but I haven't seen anything
definitive on it.  A pointer to more info on arc suppression for dynamically
braked motors would be appreciated.  Google turns up lots of patent
applications, but I haven't found anything that substantiates the claims.
--
Dave M
A woman has the last word in any argument. Anything a man says after
that is the beginning of a new argument.

The motor is out of the unit. There are no brakes involved. Lenny

If you have a universal motor (most likely), then I suspect a problem
in the field.

  If you inspect the motor's wiring, you should see one of the leads
going to the field and back out and then to a brush, or, the motor
allows the wires out side for you to wire it this way.

  It's common for these types of motors to short in the field there by,
heating up faster than it should and sparking a lot on the brushes.
Also, you may notice lack of power.

  The field could look and check good on a mega but still have shorted
turns in it. You need to know the correct ohms to determine that.

Jamie

I would never be able to determine correct resistance. How about the
run current? If the brushes are sparking should I expect to see a
substantial increase in line current? On second thought the run
current would probably vary depending on load, so I don't really know
how much information I could get from that either. I really don't want
to give up on this thing but a new motor is more than 2/3 the cost of
replacement so it's starting to look that way. I just wish that there
was a definitive way to determine exactly what the problem is. Lenny

a lot of those motors spark anyway. That is the  nature of them. They
don't last very long! that is, the brushes don't last long in them.

  When I say spark as in normal, I am only talking about a slight visual
spark on the corners. You shouldn't be seeing blacken sparks with in a
couple of run times though.

   How good is the bearings in this motor?

  Jamie
Click to expand...
The bearings are fine, and as far as the sparking goes, I know what
you mean about a "slight" spark at the brush contact points. I've seen
that before. This however is like a a white hot spark mostly at one
brush only which is strange, and quite large too. You can even hear it
burning over the motor noise. Lenny
 
The usual causes for excessive sparking at the brushes
and commutator when the brushes are new are;

- weakened brush springs which aren't holding the brushes
firmly enough against the commutator,

- or the brushes contact surfaces do not conform fully
to the curvature of the commutator


--
SeaMonkey
 
On Apr 22, 10:03 pm, SeaMonkey <SeaMonkey.9da7...@diybanter.com>
wrote:
The usual causes for excessive sparking at the brushes
and commutator when the brushes are new are;

- weakened brush springs which aren't holding the brushes
firmly enough against the commutator,

- or the brushes contact surfaces do not conform fully
to the curvature of the commutator.

--
SeaMonkey
Click to expand...
Well the brushes and springs are new and the brushes come pre curved
for the commutator so I don't think that is the problem. I'm going out
of town for two weeks but when I get back I'm going to take another
look at which brush it is that is excessively burning and I'll add it
to the thread. Thanks everyone for all the suggestions. Lenny
 
klem kedidelhopper wrote:
Well the brushes and springs are new and the brushes come pre curved
for the commutator so I don't think that is the problem. I'm going out
of town for two weeks but when I get back I'm going to take another
look at which brush it is that is excessively burning and I'll add it
to the thread. Thanks everyone for all the suggestions. Lenny
Click to expand...

Try running the motor on 12 to 24 VDC to seat the new brushes. I
used to polish the armature with a gray ink eraser while running the
motor this way, when I repaired vacuum cleaner motors.


--
You can't have a sense of humor, if you have no sense.
 
On Apr 24, 7:52 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:
klem kedidelhopper wrote:

Well the brushes and springs are new and the brushes come pre curved
for the commutator so I don't think that is the problem. I'm going out
of town for two weeks but when I get back I'm going to take another
look at which brush it is that is excessively burning and I'll add it
to the thread. Thanks everyone for all the suggestions. Lenny

   Try running the motor on 12 to 24 VDC to seat the new brushes.  I
used to polish the armature with a gray ink eraser while running the
motor this way, when I repaired vacuum cleaner motors.

--
You can't have a sense of humor, if you have no sense.
Click to expand...
The new brushes are pretty well shaped to the arc of the commutator
but I guess it doesn't hurt to try. You can do this to a 120VAC motor
without hurting it though? Lenny
 
klem kedidelhopper wrote:
On Apr 24, 7:52 pm, "Michael A. Terrell" <mike.terr...@earthlink.net
wrote:
klem kedidelhopper wrote:

Well the brushes and springs are new and the brushes come pre curved
for the commutator so I don't think that is the problem. I'm going out
of town for two weeks but when I get back I'm going to take another
look at which brush it is that is excessively burning and I'll add it
to the thread. Thanks everyone for all the suggestions. Lenny

Try running the motor on 12 to 24 VDC to seat the new brushes. I
used to polish the armature with a gray ink eraser while running the
motor this way, when I repaired vacuum cleaner motors.

The new brushes are pretty well shaped to the arc of the commutator
but I guess it doesn't hurt to try. You can do this to a 120VAC motor
without hurting it though? Lenny
Click to expand...

I rebuilt hundreds of motors with no problems. A variable power
supply is great. Most of the motors ran the right speed between 6 & 16
volts. The wide gray eraser is used to polish the surface and reduce
arcing. Polish the armature, and let the motor run at the reduced speed
for a while to seat the brushes. Use just enough pressure to just
slightly slow the motor. This will prevent the eraser from getting hot
& melting or burning. I used to refer to the process as a 'Briarhopper
Armature Lathe'. I refused to show anyone how I took a nasty, worn
armature and made them look brand new, but they kept coming back for
rebuilt motors for their used vacuum cleaner business. The best part
was that they would give me hundreds of motors that 'Aren't worth
fixing', then buy them back. ;-)

Even though the curve is close, they aren't a great match until they
are run for a while.

http://ak.buy.com/PI/0/500/208376870.jpg shows the type I used. I
used to be able to buy solid gray, but this type should work OK and
should be available anywhere that sells a decent selection of office
supplies.


--
You can't have a sense of humor, if you have no sense.
 
On 4/26/2012 8:04 AM, Michael A. Terrell wrote:
klem kedidelhopper wrote:

On Apr 24, 7:52 pm, "Michael A. Terrell"<mike.terr...@earthlink.net
wrote:
klem kedidelhopper wrote:

Well the brushes and springs are new and the brushes come pre curved
for the commutator so I don't think that is the problem. I'm going out
of town for two weeks but when I get back I'm going to take another
look at which brush it is that is excessively burning and I'll add it
to the thread. Thanks everyone for all the suggestions. Lenny

Try running the motor on 12 to 24 VDC to seat the new brushes. I
used to polish the armature with a gray ink eraser while running the
motor this way, when I repaired vacuum cleaner motors.

The new brushes are pretty well shaped to the arc of the commutator
but I guess it doesn't hurt to try. You can do this to a 120VAC motor
without hurting it though? Lenny


I rebuilt hundreds of motors with no problems. A variable power
supply is great. Most of the motors ran the right speed between 6& 16
volts. The wide gray eraser is used to polish the surface and reduce
arcing. Polish the armature, and let the motor run at the reduced speed
for a while to seat the brushes. Use just enough pressure to just
slightly slow the motor. This will prevent the eraser from getting hot
& melting or burning. I used to refer to the process as a 'Briarhopper
Armature Lathe'. I refused to show anyone how I took a nasty, worn
armature and made them look brand new, but they kept coming back for
rebuilt motors for their used vacuum cleaner business. The best part
was that they would give me hundreds of motors that 'Aren't worth
fixing', then buy them back. ;-)

Even though the curve is close, they aren't a great match until they
are run for a while.

http://ak.buy.com/PI/0/500/208376870.jpg shows the type I used. I
used to be able to buy solid gray, but this type should work OK and
should be available anywhere that sells a decent selection of office
supplies.


There used to be a specific abrasive 'stone' used for that process and
Click to expand...
it was very effective, especially where a high power tool had to be
ready for use immediately (seating the brushes that is).
 
Rheilly Phoull wrote:
There used to be a specific abrasive 'stone' used for that process and
it was very effective, especially where a high power tool had to be
ready for use immediately (seating the brushes that is).
Click to expand...

I heard about them about 30 years ago, but cound never find anyone
with them in stock, so I came up with the other method. I would get
catalogs of motor parts that listed them, but they were always on
backorder.


--
You can't have a sense of humor, if you have no sense.
 
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