Carbon brushes, how do they attach the wire?
 

I was taking to another poster via irc and I wondered how the copper leads are attached to
carbon brushes for motors. There isn't any way I'm trying to google that one.

Can anyone here explain the process?

Thanks,

Wes

Carbon brushes, how do they attach the wire?
 

"Wes" wrote in message
...
I was taking to another poster via irc and I wondered how the copper leads
are attached to
carbon brushes for motors. There isn't any way I'm trying to google that
one.

Can anyone here explain the process?

A lot of them are in molded Wes.
Go ahead and smash a bad one with a hammer sometime.


JC

Carbon brushes, how do they attach the wire?
 

Wes wrote:
I was taking to another poster via irc and I wondered how the copper leads are attached to
carbon brushes for motors. There isn't any way I'm trying to google that one.

Can anyone here explain the process?

Thanks,

Wes


All of the ones I've ever seen had a copper "cup" that the carbon brush sat in.

The copper thingie has a spring attached to the back side to apply pressure so
the brushes stay in contact with the rotor (stator?) in the motor.


Richard

Carbon brushes, how do they attach the wire?
 

"John R. Carroll" fired this
volley in :

A lot of them are in molded Wes.
Go ahead and smash a bad one with a hammer sometime.


Well... sintered.

The copper wire may be just embedded in the matrix, with some length
of it compressed in the finished form, or there may be a ferrule on
the end of the wire, or they may dip the end of the braid in some
copper/carbon/flux goo, and sinter that at the same time they're doing
the body of the brush.

In any case, after baking out in a kiln at several tens of tons per
square inch on the material, it becomes a near-homogenous solid, with
the wire, ferrule, or metal mix embedment firmly incorporated as part
of the structure.

LLoyd

Carbon brushes, how do they attach the wire?
 

On Fri, 23 Jan 2009 18:43:20 -0500, Wes wrote:

I was taking to another poster via irc and I wondered how the copper leads are attached to
carbon brushes for motors. There isn't any way I'm trying to google that one.

Can anyone here explain the process?

Thanks,

Wes

Others have said how "they" do it, as in production. It is also easy
to plate copper onto carbon, and then solder (or ultrasonically weld)
a lead to the copper. I've electroplated carbon rods for a carbon-arc
torch in a coke bottle using copper tube for an anode and copper
sulfate solution as juice.

Carbon brushes, how do they attach the wire?
 

Others have said how "they" do it, as in production. It is also easy
to plate copper onto carbon, and then solder (or ultrasonically weld)
a lead to the copper. I've electroplated carbon rods for a carbon-arc
torch in a coke bottle using copper tube for an anode and copper
sulfate solution as juice.

I assume you've done this. Does the copper carbon bond have good
mechanical strength? most servo motor brushes have a very small area
on the end of the brush.

Karl

Carbon brushes, how do they attach the wire?
 

On Jan 23, 6:43*pm, Wes wrote:
I was taking to another poster via irc and I wondered how the copper leads are attached to
carbon brushes for motors. *There isn't any way I'm trying to google that one.

Can anyone here explain the process?

Thanks,

Wes

Because carbon is conductive you can plate it with copper and then tin
the copper or solder to it. Not the only method as little metal boxes
and springs also can be used for a mechanical connection, so- it
varies.

Carbon brushes, how do they attach the wire?
 

On Sat, 24 Jan 2009 09:14:34 -0500, Karl Townsend
wrote:


Others have said how "they" do it, as in production. It is also easy
to plate copper onto carbon, and then solder (or ultrasonically weld)
a lead to the copper. I've electroplated carbon rods for a carbon-arc
torch in a coke bottle using copper tube for an anode and copper
sulfate solution as juice.

I assume you've done this. Does the copper carbon bond have good
mechanical strength? most servo motor brushes have a very small area
on the end of the brush.

Karl

I never tried brushes. I think it would work if one plated a "cap"
on, probably not if one just plated on a spot or pad. I think the
latter would peel fairly easily.

Carbon brushes, how do they attach the wire?
 

In many cases, contact is only by pressure against the spring inside the brush holder. This seems
to suffice for small motors in the sub-HP range.

Bob Swinney
"Don Foreman" wrote in message
...
On Sat, 24 Jan 2009 09:14:34 -0500, Karl Townsend
wrote:


Others have said how "they" do it, as in production. It is also easy
to plate copper onto carbon, and then solder (or ultrasonically weld)
a lead to the copper. I've electroplated carbon rods for a carbon-arc
torch in a coke bottle using copper tube for an anode and copper
sulfate solution as juice.

I assume you've done this. Does the copper carbon bond have good
mechanical strength? most servo motor brushes have a very small area
on the end of the brush.

Karl

I never tried brushes. I think it would work if one plated a "cap"
on, probably not if one just plated on a spot or pad. I think the
latter would peel fairly easily.

Carbon brushes, how do they attach the wire?
 

On Jan 23, 5:43*pm, Wes wrote:
I was taking to another poster via irc and I wondered how the copper leads are attached to
carbon brushes for motors. *There isn't any way I'm trying to google that one.

Can anyone here explain the process?

Thanks,

Wes

Many patents describe alternative ways of bonding the braid or shunt:
http://www.google.com/patents?q=carbon+brush+shunt
This one uses powder mixture with hot isostatic pressing (HIP):
http://www.google.com/patents?id=3-o...BAJ&dq=5168620

Carbon brushes, how do they attach the wire?
 

wrote in message
...
On Jan 23, 5:43 pm, Wes wrote:
I was taking to another poster via irc and I wondered how the copper leads
are attached to
carbon brushes for motors. There isn't any way I'm trying to google that
one.

Can anyone here explain the process?

Thanks,

Wes

Many patents describe alternative ways of bonding the braid or shunt:
http://www.google.com/patents?q=carbon+brush+shunt
This one uses powder mixture with hot isostatic pressing (HIP):
http://www.google.com/patents?id=3-o...BAJ&dq=5168620

Yeah, That's what we called "molded".

JC