Electric Motor Repair

Electric Motor Repair

I was gathering parts to bring up to my car last week, and I’m about ready to install the rear panel that fits under the rear window. At this point, the safest place for this panel is installed on the car, but one last piece had to be fixed. I was about to bolt the blower motor onto the back of the panel when my better judgment wanted to test the motor. As I hooked a 12 volt power supply to the the motor, it sprang to life, but it sounded labored, and didn’t seem to push any air from the fins of the fan. There were no places on the housing for oil, so the motor had to be taken apart.

I’ve taken motors apart in the past, and had success in cleaning them and getting them to work again, but I always hesitate because of something I did when I was 13. I was a bored teenager, and one summer day I decided to take apart my father’s electric drill to see how it worked. I don’t know why, but the curiosity may have come from messing around with model electric cars that I raced on a table top track. I was teaching myself about electric motors, and wanted to see if the motor inside that drill was the same as the one in the little cars.

After about 15 minutes, I had the most of the drill apart, but when it came to putting it all back, I couldn’t get the parts back together. I tried, and tried, but my limited mechanical knowledge had been exceeded. Not knowing what to do, but knowing that I was in trouble if the truth of my actions came out, I threw the previously operational drill in the trash! A few months later, when my father had to buy a new drill because he couldn’t find the old one, I breathed a sigh of relief. My penance for this stunt is my eternal hesitation in taking any electric motor apart for fear that I may not be able to put it back together again!

My blower motor came apart pretty easily, and as soon as I cracked open the case, I could see the problem. Moisture had gotten into the housing, and rust was forming between the armature and magnets. Although the motor could spin, the rust was slowing things down. With some 400 grit sandpaper, I removed all the rust that was on the steel parts. The commutator was a little dirty from the brushes sitting idle in one spot for years. so I took some 800 grit sandpaper, and cleaned up the contact area. The brushes looked O.K., so I put the whole thing back together.

Not having a 12 volt power supply at home, I bagged the motor and took it to work today to check it. Now it spins with much more speed than it had, and will do a fine job when back in the car. At least I didn’t have to hide this motor in the trash!

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