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Dumore 44 how to breakdown motor?

Ralphxyz

Aluminum
Joined
Nov 22, 2015
I need to replace the cord on my Dumore 44 Tool Post Grinder.

I have not brokedown a motor in 50 years and then I do not remember if I got it put back together correctly.

So what do I need to do? I cannot find any motor repair shops locally so "think" I'll do it myself.

Any and all help/comments appreciated.

Ralph
 
Thanks redlee, if only it was that simple. You obviously do not know what Dumore #44 motor looks like.

I have seen reference in other threads where owners seemed to casually have taken the motor apart to examine the bearings.

I really do not want to do something wrong.
The motor works fine but the cord is raggard.

Ralph
 
Did that a while back, on the same model. I do not recall anything odd or tricky about it.

Do take out the brushes first, that way they will not snap in toward the shaft when you pull out the rotor. As I recall, you take out several visible screws on the end bell opposite the pulley shaft, and that end bell slides out. Then you can pull out the rotor. I believe you need to remove the stator assembly to get at the cord area. That is two more screws, and you need to keep the wires clear of the rotor when you re-assemble.

Do you have the manual with parts breakdown?
 
Thanks JST, yes I have the manual which illustrates the parts but not the procedure. Your explanation makes it easier it more or less confirms what I was thinking so it is a big help.

Ralph
 
Thanks redlee, if only it was that simple. You obviously do not know what Dumore #44 motor looks like.

I have seen reference in other threads where owners seemed to casually have taken the motor apart to examine the bearings.

I really do not want to do something wrong.
The motor works fine but the cord is raggard.

Ralph
Yup your right,thought it was a regular electric motor. Got a pic ?
 
Exploded view

afmhpaP.jpg
 
Ralph,

As JST mentions, the motor will have to be dismantled to gain access to its internal electrical connections.
For someone not accustom to this type of task, it will be intimidating.

Match-mark using a prick punch or permanent marker pen on the shaft end motor bracket (22) with the field housing (13) FIRST so upon reassembling,
the two components are put back in their proper arrangement.

Already mentioned, remove the brushes.
Remove the pulley from the motor shaft.

Next, remove the four end bracket screws labeled (23) on the parts breakdown.

Using a cold chisel (or a screw driver) and hammer, carefully break apart the mating register fit of the end bracket (22) with the motor field frame (13).

Carefully pry apart the end bracket from the field frame. The armature should stay with the end bracket
as it’s being pulled out.

The next steps are going to be the more difficult.

The two long screws (20) holding the wound field in the frame will have to be removed followed by
the internal fan shroud (19) and the two spacer bushings (18).

Carefully match-mark the wound field’s position in relation to the housing BEFORE REMOVAL to know
its proper position for reassembling. The mark should overlap one item to another so upon reassembly,
it is put exactly back in the very same position. (This has to do with the motor’s brush neutral which we won’t go further into).

In pulling out the field, the leads on it will likely not be very long and you will have to
disconnect –things- as you pull the field from the frame.

AGAIN! Mark and identify how the wires are connected.

Once the field is removed from the frame, you’ll have to assess your wiring job.
On a motor like this, there are typically small spring-like end connections to the brush holders
that will (may) have to be disconnected (pried off the brush holders) to fully remove the field.

Depending on the age of the machine, some of the wires may be brittle and require additional electrical
sleeving.

There’s not a lot of room for excessive length wires to be laying around inside the motor when
you begin to reassemble the item. So as you replace/install a new cord, consider the lengths of the original
wiring as a guide.

Re-assembling the motor will require it to likely be held in a position so you can drop things back in.
Gingerly hold the frame (13) in a vice with what will be the output shaft pointing toward the ceiling if you will.

One of the tricky tasks will be aligning the bushings on the field laminations with the field mounting holes
before replacing the internal fan shroud and so on.

And as mentioned earlier, as you begin re-installing –things- be on the lookout for how the internal
wiring finds its home. No wires should obstruct the armature from turning, or even remotely rubbing on it.

Reassemble in reverse order.

Good Luck!

John
 
Duh... Ha Ha, it did just occur to me... the pulley does not have to be removed from the motor shaft.
Sorry 'bout that.

John
 
Thanks everyone, used to be a day when I would just tear into something like this now I wish I could find a motor repair shop, possible I will look around further away. I "think" I can do it but ...

Ralph
 
There is uneven wear on one of the brushes. That is a link [one of the brushes] you can click on the + to get a bigger view but not very clear sorry.

About 3/16" no wear on the left. The one on the right shows normal wear.

Does this mean possible trouble?
So all the more reason to take it to a motor repair shop to do the cord?

Ralph
 
Can't see squat in the picture except that they are black in color....and may be motor brushes.

Not that unusual to see more wear on one brush, but not entirely normal. Might be a reason, might not.

Does it RUN? That is the first thing II'd check out. It may not be worth having a motor shop do anything with it, actually. It's a small TPG.... OK. I have one in my own shop, it's OK, nothing special. Just take it apart and fix the cord.

Remember, the folks who put it together were Wisconsin farm folks who were trained to put together TPGs.... Not to design them, or fix them. If they can do it, you can do it.
 
Thanks, the miss wear is noticeable only about 2/3 of the brush is making contact. Sorry about the picture. Could just be how that brush was setting the other brush looks normal.

The motor runs fine.

Ralph
 
Well work in progress!! I have the motor torn down ready to put it back together.

Went pretty easy no surprises or gotchas.

Ralph
 
I reassembled the motor, ta dah!!

Plugged it in and turned it on, NOTHING.

Well at least there wasn't any sparks.\

While looking at the motor thinking about having to tear it down again
I noticed something, DUH you can tell I am not used to working on motors, I forgot to re-install the brushes, DUH.

Re-installed the brushes, turned the motor on and ta dah it works!!

Thanks everyone for the help and JST for the encouragement.

Ralph
 








 
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