If this is your first visit, be sure to
check out the FAQ by clicking the
link. You must register
before you can post: click the register link to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.
Martin has done a great job in showing how to rebuild these motors which are very similar to all the little motors used over many years and locations.
I would like to add: IF you have a motor that runs but is running slowly there is a good chance it only needs to have the bushings oiled. The exposed shaft end is easy to work oil into - just add a drop. The enclosed end of the motor is not accessable unless it is disassembled. I have had good luck just drilling a small hole in the center of the motor's rear housing and adding a drop or two of oil via a pin oiler. Don't over do it but give the oil a chance to seep into the bushing. Moving the shaft for and aft as well as rotating it helps to work the oil into the bushing. A bit of sealer of your choice can close the hole you drilled.
Nothing is better than a complete cleaning and rebuild & I realize this is not the "correct" way to fix a problem but it might get a window or fan motor running smother and quieter without a tear down.
Wonderful series on repairing window/p/s motors. I'm sure this will save me from breaking parts and being frustrated later. How are you cleaning the armatures and stator? They come out looking brand new. Also, have you ever found a source for the washers used as shims inside the motors. Every once in a while some of these will come out broken.
Thanks again for the great post in TRL.
Nyles
Use contact cleaner and plenty of rags.
Do not sand the commutator segments. Brushes 'form' the copper by impregnating carbon into the surface. That lubricates the brushes and keeps them from wearing.
The only time we dress commutator segments is when they glaze from excessive grease & dirt deposits, or if they deform into 'cup', taper or egg shapes. These are extreme cases.
Scrape in between the copper segments so they are undercut, make sure the brushes slide freely and you're ready to go.
I found 2 different style motors when I rebuilt mine. One style has the brushes at the coupling end of the motor and the other style had the brushes located at the bottom of the motor opposite the coupling drive. The style with the brushes nearest the coupling requires more gentle handling as the brush holders can break really easily. If your motor still runs, I cleaned the end of the shaft by running the motor and using a fine grit sandpaper on the shaft to polish it. It still took a little effort to get the shaft out of the bearing. Once you get he motor apart, there is a felt washer around both of the brass bearings. I put a couple drops of oil in this area and the felt soaked it up. It should provide long term lubrication for the brass bushing/bearing. I used some .030" wire I had in the garage to make the pins to retain the brushes if you have the style where they are located in the bottom of the motor. Here is another link in the TRL with some more pics, just in case you missed it: http://www.squarebirds.org/images_mo...indexNyles.htm
Nyles
I've taken 6 of these apart that worked in one direction only. One set of field coils in each one is badly discolored and obviously the problem. Are there any fixes for this other than rewinding the coils?
Carl
...One set of field coils in each one is badly discolored and obviously the problem. Are there any fixes for this other than rewinding the coils?
Carl
No, and yes. It depends on how badly you want to save the motor.
If replacing the field coil is out of the question, you could mount and wire two relays and use it like a conventional two-wire motor.
One relay directs current for UP and the other relay reverses current for DOWN. (In crane language it would be, Hoist and Lower.)
This only works if your motor uses a separate ground wire, not connected to the case. Equally important is electrical interlock, where both UP and DOWN could become energized simultaneously. This shouldn't happen using a rocker switch but it certainly could using two (one mounted at each window). Properly wired relays prevent this. If one relay is energized, it opens the other from energizing.
I have relays and can provide this setup for you. With my setup, the window button only passes 'control power' for the relay coil. I let the relay contacts handle all the motor power. So at each motor, I require a power wire (constant on) and a solid ground wire. Power may be picked up from the power window wire that is already connected to the relay and circuit breaker on the firewall.
BTW, my setup works for GM-type motors as well. They only have two wires and are much cheaper and more plentiful than Ford motors. Later in years, Ford switched to those motors.
Dave, that's a great fix. Wouldn't have thought of using individual relays.
Carl, did you do resistance checks across the coils and compare the results against a good coil? Should give an indication if they are shorted. I had some dark coils in 2 of my motors, but they still work fine. You could also check with an electric motor shop to see if coils are available. I had a shop rebuild a skill saw for me and it was pretty cheap. Just a thought.
Fixed one motor so far this morning. It's a fairly easy process after viewing the information on this website. There was black greasy gunk on the shaft where the brushes touch. After cleaning with contact cleaner and a cloth, plus cleaning out the grooves, there is a VERY noticeable change in how the motor sounds. It sounds like "new"...
...There was black greasy gunk on the shaft where the brushes touch...
Yep, that's the commutator! Your finding is typical; current tries hard to arc through that greasy dirt. Sometimes, it leaves a hard glaze (which needs to be removed) but most of the time a good cleaning, like you did, is all that is necessary.
Another condition that is typical... I've never seen the brushes worn down. They don't really go very far, even in fifty years. It seems that all lubricating grease does is pick up dirt and get into everything inside. So, only give a light lube.
Nice job, Greg. You just made your motors good for another fifty years for the cost of a can of cleaner and a rag. Did you happen to take any pictures? - Dave
Comment