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Old 05-18-2009, 02:03 PM   #10 (permalink)
Joe of Loath
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Location: Bristol, UK
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Quote:
Originally Posted by slurryguy View Post
It doesn't look as bad as many motors. Don't let the appearance scare you.

I have lots of comments. Many that you probably are not going to like, but at least I'm being honest.

1.You have very little drive end shaft to work with. This is probably the biggest potential problem. There is almost nothing there to attach a sprocket to. The good news is that the drive end shaft appears to be keyed, but it's difficult to tell from the picture. Extreme close up pictures of the drive end shaft might be helpful.

2.Are you saying that the drive end motor plate is bolted to the hydraulic pump and has the bearing in it? That's good.

3.If the Drive End motor plate is one piece permanently part of the hydraulic pump, that's probably a show-stopper for this motor for you. It would be a lot easier (and cheaper) to go try to find a better motor than to try to make your own drive end plate and seat a bearing in it. BE CERTAIN to solve this issue and fully understand how you are going to mate the drive end motor shaft with the rest of your drive train before investing ANOTHER PENNY in this motor.


4.As far as the rust goes. No problem. This motor is actually reasonably clean compared to some that get salvaged. A wire brush and sandpaper will go a long way. A good cleaning and a little paint will pretty it up. Just don't paint anything copper, and don't paint the brush holder area at all.


5.Inspect the armature windings very closely. Look for burned or melted windings. Anything like that is the kiss of death. Recycle the motor and find another one. You'll be glad you did. Trying to re-wind an armature is the punishment the devil gives to mass murders, rapists, and child molestors.

6.Inspect the field stator windings closely as well. Look for burned areas there too. Sometimes damaged field windings can be repaired if they aren't damaged too badly. Hopefully yours will only be dirty. You'll probably want to remove the bolts on the side of the field housing so that you can remove the field windings entirely. That will make it a lot easier to clean everything. That is also the best time to paint the housing your favorite glow-in-the-dark color.


7.I suggest 4 brand new brushes and 4 new springs, but only invest the money after you are positive that the rest of the motor is going to work for your application. You can probably clean the brushes and springs you have and get the motor to function for experimentation, but new brushes and springs are in order before you put this motor back into service.

8.You'll also want to confirm the direction the motor spins is correct for your application. You can drill new mounting holes for the CE plate to adjust the timing and/or change the direction that the motor spins. Again... before trying to do this, make sure you will be able to mount the DE to your drive train, and have confirmed the rest of the motor is okay first.

9.Spinning the commutator on a lathe wouldn't be a bad thing. It's hard to tell from this picture, but it looks to be in pretty good shape. Look at it closely. Look for burns or pits. Look for insulating mica trying to come out from between commutator contacts. (That would be the kiss of death for this motor too. Better to find another motor than to try to repair a commutator that's falling apart.)

10.You should also test the commutator electrically. Use an ohm meter to be certain that no adjacent commutator contacts are shorted together, but also make sure that the appropriate opposing contact has continutity. Shorts where they shouldn't be in the commutator/armature are the kiss of death. Send the motor to the recycler.


I hope this helps.

Have fun. If everything checks out, especially the armature/commutator, the DE plate/bearing, and you're positive you can mate the shaft to your drive train, this may be an excellent motor for you.

A little Love and Elbow Grease can change the appearance to make it look like new again.
Wow, lots of input here I numbered your comments in the quote so I can reply easier.

1. Yeah, it's pretty short, but keyed. I can machine up a mount to go in there, whether it ends up true is another matter...

2. The endplate is separate to the pump. I'll try get it apart later, but it might need some persuasion.

4. I Probably won't paint it, but I'll dig out my wire brush. It should end up OK.

5. The armature looks fine so far, but I can see what looks like either an oil sheen, or heat discolouration on some of the metal parts of the armature. As it looks ok, I think I'm ok.

6. I can't get the bolts on the housing (that hold whatever bits replace the magnet on series wound motors) off. They're phillips headed, and no amount of persuasion got them off before, so I doubt they're going to loosen off now.

7. OK, the brushes and springs probably come in sets of 4 anyway, and in the RC world (albeit with tiny little motors) it's good practice to replace them once you skim the commutator. Would I have to press the brush with the broken spring to get it to run? Or will it limp round with 3 brushes working?

8. The direction is noted on the serial number plate, and my friend and I switched the quad axle round to compensate. Strangely this is a clockwise motor, I've never seen one before.

9+10. I'll find the volt meter and have a look at the commutator. AFAIK it's intact, and actually barely worn compared to the untouched copper ends of it. I think it was a chance failure that got this motor chucked in the skip.

Sorry I'm doing the 'bulletproof monk' answering your questions with more questions, but I don't know much about series wound motors.

Thanks
Joe

P.S when people refer to motors as '8 inch' or '9 inch', is this referring to the length or diameter of the motor?
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