Hello all,
I reciently purchased a late 50’s 14″ Dewalt Radila Arm Saw. While replacing the cords I found that the wires coming out of the motor are very brittle. It is a dual voltage three phase 3 horse motor so there are nine leads. The leads are the old cloth insulated type and as I move them I can hear them cracking. I disturbed them as little as possible and have conected the new cord. I can’t see any places where the conductors are showing…. but this is obviously a bad situation. The insulation is very brittle, when I stripped the leads to make the new connections the insulation just crumbled. While I am rehabing this old monster I would like to replace these wires. So are these leads easily replaced? Is it a matter of just opening the back of the motor and resoldering new ones? Or is this something better left to a motor shop. I am generally pretty skilled at fixing these sort of things, but if it is overly difficult Ill just wait till the motor burns up (maybe never) and have the whole thing rebuilt.
Mike
Replies
Mud, I have faced that situation many times. Here's what I do:
Carefully peal back some of the insulation that usually is there to press those leads to the windings-this exposes the wire covering (cloth or rubber) which should be in good condition as it has not been exposed up to now. Then I use something known to me as "sister flex" which is a tubing that is slipped over the wire then warmed up with a hot air gun-it shrinks onto the wire. You can use that or there is also another type that just slips over-usually a heat resistant type.Then tie the leads back onto the windings.
Sometimes I have just cut the old leads near to where they emerge from the windings, soldered new ones on , and insulated the join with the magic shrinking stuff.Obviously when soldering take care not to drop solder onto the windings.
I am assuming that the motor has not been over heated. You may also consider taking it to motor rewinder who can check it out and if all is well they can re-varnish the windings and "bake", after sorting the leads out-while you are replacing bearings?
Philip,
Sounds like you know what the problem is. I thought about using shrink wrap tubing as well. But this is a TEFC motor so the leads dissapear into the motor housing with no way to get to them, without opening the motor housing that is. Sounds like you were describing soldering new leads to the windings. This is what I would like to do, but I am afraid that once I open the motor housing I will find it is more complicated than I thought. I really do not want to spend a day replacing these leads only to have a bearing go bad next month. After all the saw is about 50 years old. Ill check on a rebuild price as well.
Mike
You might want to take this question over to the Old Woodworking Machines forum. See http://www.owwm.com. I think the likely answer is that this job is best left to your local electric motor shop. These old Delta motors are outstanding, but some models are very tricky to get back together. The last one I worked on (with very similar lead problems) was a real bear.Pete
.That is what I am afraid of. I called a motor shop today and they told me it would be about $400!! and a full rebuild is $800. I think that those are very high prices. I'll try another shop tomorrow. The guy was actually very helpfull and told me I should just shrink wrap the exposed leads and not worry about the inner part. I will post on OWWM, thanks for the help.
MIke
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