[GreenKeys] Safety tip - AC wiring

[Jones, Douglas W]

On Mar 8, 2017, at 10:31 AM, Nick wrote:

> Well, I am a rookie and don't know a whole lot about electronics. 
> What do you do with an old piece of equipment and a not so good looking wire coming out of the motor. I never opened up a motor housing to rewire the cord. 
> Is it possible and how difficult is it to replace  ???

Been there, done that.  See my writeups from Apr. 25 and 29, 2014:
-- http://www.cs.uiowa.edu/~jones/pdp8/UI-8/log2014b.shtml#2014-04-25

Click on the photos for an enlargement.  Typically, you'll need lacing tape, because the lacing on the ends of the stator windings typically holds the leads in place.  Then, you need crimp connectors to attach the new leads to the carefully scraped end of the enameled motor winding.  You end up having to replace all the old lacing with new lacing, and it's an interesting task to determine the lacing pattern and follow it.

Only connect one motor winding at a time, and try to match the wire colors so when you put the motor back into its circuit, it still turns the same way it originally did.

Typical induction motors have a few screws that run the length of the body, through holes toward the outside of the stator laminations.  Remove these screws, and the end caps are held on by friction.  Use a very sharp knife to get into the space between the motor end cap and the shell, and you can start it prying off.  You may as well pry off both end caps so the rotor is out of the shell before you work on it, because then the rotor isn't in the way and the stator assembly will sit comfortably on your work table.

(The motor in the photo is about the same size as a TTY motor, by the way.  It's a capacitor run motor, not capacitor start -- that makes everything easier because there's no starting switch or relay involved.

		Doug Jones
		jones at cs.uiowa.edu