Dumore Motor brush holder removal

I have a Dumore model 11-011 tool post grinder that needs a new power cord.

In order to replace the cord, I need to remove the commutator to access the field windings.

The field windings are attached to the brush holders as well as the power cord.

The wires going to the brush holders are somehow stuck to the brush holders.

The brush holders are held in place by a set screw.

I've removed the set screw from each holder but they won't budge.

Suggestions?

I've attached several pictures of the partially disassembled motor and closeups of the brush holders (both outside and inside the motor).

Gary

The terminal appears to be a crimped clip as shown in pics two and five.
Is this the case?

Yes. The wire is attached to the brush holder with a crimped spade terminal lug. One is completely seated. The other one has come partially loose such that I can see about half of it sticking into the air.

Gary

garyrice said:

I have a Dumore model 11-011 tool post grinder that needs a new power cord.

In order to replace the cord, I need to remove the commutator to access the field windings.

The field windings are attached to the brush holders as well as the power cord.

The wires going to the brush holders are somehow stuck to the brush holders.

The brush holders are held in place by a set screw.

I've removed the set screw from each holder but they won't budge.

Suggestions?

Gary

Click to expand...

Having done this myself, I am a little confused by your question......

You should have (and did) removed the brushes and pulled the armature and commutator assembly (the rotor).

At that point, you have as much access as you are going to have, unless you pull the field assembly, which should be possible without having to remove the brush holders.. At least I could on the model 44 I repaired.

There is not a lot of room in there, but there is "enough". I was able to do the repair without extra drama. You really only need to connect to the same wires the cord originally connected to.

The brush holders usually are made of Bakelite or a similar material and are easily broken. They are originally held in place by a set screw but they seem to swell, possibly from moisture, and they are often stuck. They will not stand much force, so if at all possible to work with them in place, do not try to remove them.

Bill

JST said:

You should have (and did) removed the brushes and pulled the armature and commutator assembly (the rotor).

At that point, you have as much access as you are going to have, unless you pull the field assembly, which should be possible without having to remove the brush holders.

There is not a lot of room in there

Click to expand...

Too true. In fact there is so little room that removing the field assembly is absolutely necessary to access the wires connected to the power cord.

Remember that a model 44 is slightly larger than my model 11.

Needle nose pliers should be the only tool I would need to unclip the spade terminal lugs from the brush holders. But the lugs won't budge.


Gary

Well it turns out that someone had been inside the grinder before and soldered the spade lugs to the brush holders.

I gave the end of the motor a bath in lacquer thinner followed by a bath in tarn-x. That process revealed the bright silver color of solder. A quick bit of heat from a soldering pencil loosened the lugs and the motor came apart easily.

Gary