Jabsco Electric Conversion: Motor Commutator Refurbishment

[nigelmercier]

I've decided to have a go at refurbishing the seized motors on two Jabsco Electric Conversion kits...

The story continues with my Motor Commutator Refurbishment...

I wasn't exactly sure how many shims came out from behind each bearing, and one of them also has a spring washer under the bearing (I guessed it went at the top, where the commutator is [Later] this is correct); I also planned to omit the rubber gaskets and use silicone. Therefore I decided that I needed to refurbish the commutator to remove the ridge where the brushes originally rubbed.

This is one of them mounted in my lathe, you can see the ridge:

Tip of the day
I don't have a fixed steady for my lathe, nor an "armature chuck" with brass jaws. However, I had a brainwave: I inserted the (well-greased) shaft into a piece of 8mm copper pipe, then tightened it in the tailstock chuck, then backed it off a little. This worked so well that I'm going to keep a stock of small-bore copper bits in my shed.

Having turned down the commutator, I mounted it in a drill press and used various grades of sandpaper to polish it up (don't want grit in my lathe), this is part way through:

As you can see, the lathe caused the copper to spill over into the gaps, the best tool to fix this was a craft knife:

Both 24V motors run OK on my 12V supply, but one of them seems to be a bit noisy. They both have new bearings, so I'm not sure why.

 

[jerrytug]

A good practical job you're doing there!
Is the noisy one also vibrating? If not, the noise will probably go away, because whatever is causing it will just be worn away. Uneven commutator possibly, it looks like a fairly rough finish.

If the noise is accompanied by vibration, which gets much worse on the full monty 24v, then you have a bent armature shaft probably, you should examine for straightness as best you can.

Not likely to be causing the noise, but when you put the knife blade in the commutator gaps, did you cut a V groove, or a square-bottommed valley, or undercut the groove? All the txt-books say you should undercut. I will put a diagram up later if I can find one, cheers Jerry

edit, new brushes and springs? Best, if you have them available.

 

[nigelmercier]

I just used the tip of the blade to clear the swarf, the mica was still well down and flat. I used an X-Acto saw at one stage, this works well also: http://amzn.to/1rpR0Rl

Yes, the surface still looks rough. The one with pictures I did the craft knife thing before the polish on the drill press, as this did not cause further swarf.

Brushes are fine, I was really only doing this because the wear point may move.

Not too worried about the noisy one, I thought I would only get one of them going so I'm glad to have it as a spare.

 

[pampas]

best under cutting tool is to grind the SET off on both sides of a 6" hack saw blade, break off a piece about 1/2" long, make a little clamp then saw down the slot to a depth equal to the width of the slot, making sure no mica is left on the sides of the copper.

 

[nigelmercier]

Just a heads-up that I found yet another Jabsco Electric Conversion motor (in a really nasty state internally) so I took it apart and took pictures as I did so, including the various techniques that worked. I won't post them until someone asks.

I'm now going to sulk because nobody said how good my idea for a "copper pipe chuck insert" was

#JabscoElectricConversion #JabscoMotor

 

[nigelmercier]

Update.

Fitted the quieter of the two motors, it's less noisy than they have ever been.

But I'm confused about something: I had to swap the power leads to make it turn the right way! WTF?

 

[rogerthebodger]

It must be a permanent magnet motor

Direction of rotation depends on the direction of rotor field which depends on the connection polarity.

 

[vyv_cox]

But I'm confused about something: I had to swap the power leads to make it turn the right way! WTF?

I had the same problem when rebuilding my windlass. I did not mark the motor case before disassembly and put it back the wrong way around. Unfortunately i had rebuilt the windlass before I found out and had to strip the whole thing again.

 

[nigelmercier]

I had the same problem when rebuilding my windlass. I did not mark the motor case before disassembly and put it back the wrong way around. Unfortunately i had rebuilt the windlass before I found out and had to strip the whole thing again.

Yes of course, the case with the magnets would go on either way, although getting my head round how rotating the case would affect it will take some doing. I'm sitting here holding my thumb and two fingers at right angles ...

I did mark the case, but then sanded and painted it

I'm going to leave it until it breaks again.

 

[superheat6k]

Just a heads-up that I found yet another Jabsco Electric Conversion motor (in a really nasty state internally) so I took it apart and took pictures as I did so, including the various techniques that worked. I won't post them until someone asks.

I'm now going to sulk because nobody said how good my idea for a "copper pipe chuck insert" was

#JabscoElectricConversion #JabscoMotor

I have noted that one, but I do have a running centre.

 

[nigelmercier]

I have noted that one, but I do have a running centre.

Wouldn't be easy, no indent on the shaft.