Rebuilding a 75HP motor

Hey everyone,

Hope you're all keeping busy with your scrap ventures. I recently bought a 75hp electric motor from a farmer that was cleaning out their field. Since I currently have the highest prices on scrap electric motors in town ($0.10/lb) I usually get a few calls every once in a while for big motors. Anyhow, I figured it would be interesting to document what it takes to have one of these units refurbished for selling. I know scrapping them could bring in a good amount of copper, but if a motor this size can sell for a few thousand dollars it may be worth selling vs. scrapping.

The pictures don't do justice to the size of this motor, but it's about 18" in diameter and about 3-4 feet long.




The first thing I did was make sure it spins freely and inspected the wiring:

I removed the back fan guard to remove all of the loose dirt/sand that was sitting in the bottom of it. Since it was sitting out in field there's quite a bit of it.

I've also cleaned the wiring area out of the random junk and wasp nests in there. The good news is that this unit passed the motor winding resistance test (not burned out) so we'll see what the rebuild shop says tomorrow about going through it to prep it for selling.

Current Investment: $120

Originally Posted by 406Refining

Hey everyone,

Hope you're all keeping busy with your scrap ventures. I recently bought a 75hp electric motor from a farmer that was cleaning out their field. Since I currently have the highest prices on scrap electric motors in town ($0.10/lb) I usually get a few calls every once in a while for big motors. Anyhow, I figured it would be interesting to document what it takes to have one of these units refurbished for selling. I know scrapping them could bring in a good amount of copper, but if a motor this size can sell for a few thousand dollars it may be worth selling vs. scrapping.

The pictures don't do justice to the size of this motor, but it's about 18" in diameter and about 3-4 feet long.


The first thing I did was make sure it spins freely and inspected the wiring:

I removed the back fan guard to remove all of the loose dirt/sand that was sitting in the bottom of it. Since it was sitting out in field there's quite a bit of it.

I've also cleaned the wiring area out of the random junk and wasp nests in there. The good news is that this unit passed the motor winding resistance test (not burned out) so we'll see what the rebuild shop says tomorrow about going through it to prep it for selling.

Current Investment: $120

Wow! 75HP? That's a bigg'un. I used to work on 5HP circulation pump motors that looked physically about that size.

Looking forward to seeing this progress!

Great project! Looking forward to following your progress!

Interesting project. Looking forward to seeing the progress as well.

Looks like you've got a couple of high volume water pumps there too. ( The red things) They're pretty durable. It's been close to 20 years since i've worked on one of those, but of memory serves, the shaft seals have to be repacked every so often. (Not expensive or hard to do.) I'm thinking the impellers inside would be fairly good size and made of brass. Might be worth it to crack one open if they're just going to scrap.

I finally got a chance to put the motor on the scale and see it's real weight. It came in at 765 pounds. Not as big as I thought, but not a small one either. I dropped it off at the rebuild shop yesterday and The rebuild shop just tested it and the unit runs! They're going to clean it, replace the bearings (they are slightly worn out), and repaint the unit for $400. They also have a buyer for the unit already! I have to negotiate out the details on the shipping (buyer is in Idaho), but I would call this experiment a success so far.

Current investment: $520

That's awesome! Love it when a plan comes together like that!