For the most part, rewinding a common size motor is not to be on the list of goals by the rewind shops. A rewind shop is quick to tell you that the motor is a scrap and it’s better to buy one, as a new motor can be bought cheaper from motor shops.
Motors contain significant quantities of metals that can be recycled for money. The copper windings are of the most valuable in the scrap motors. Next is the aluminum in windings or aluminum/steel armatures. Followed by the ferrous parts, which include cast iron or steel casings plus thin silicon steel sheets, or laminations.
With a lot of the older electric motors from AC/HVAC units or other units that found in various junk piles, dumpsters, auctions and yardsales, you can tear the motor apart for the copper inside them by using simple tools.
1. Make sure that the motor has not been used for at least one hour to limit the risk of electric shock. Then cut off what ever that are attached onto the motor.
2. Use a screw driver to loosen and remove the screws on the motor case, then remove the case. Usually there are 3 or 4 screws/bolts per motor that you need to remove. The weld on the housing can be cut or grind through.
You can also choose to use a hammer and a chisel to knock out the stator.
Then knocks the bushing/bearings/seals out of the end caps for the aluminium scrap pile.
3. Cut off one side of the copper looped wire off with wire cutters, bolt cutters or chop saw. Use a big screw driver or bar on the other end to pry the copper loops out.
Another way is to use a punch and hammer and push the strands threw the casing or pry them out threw the other side.
The copper is then cleaned of any insulated wire and put in the copper barrel. There are special copper recycling machinery for insulated wire processing. Scrap insulted wire processors can invest in either wire granulating machine or wire stripping machine for high efficiency copper recycling. Don’t burn it.
The copper content varies among different types of motors, while small motors have a higher percentage of copper per weight than heavy motors. On average, fractional electric motors are 9-10 percent copper by weight. AC motors average 7-9 percent copper; DC motors have 15-18 percent copper content.
4. The armatures and the laminates go in a scrap steel barrel.
If it is your first time to tear apart an electric motor it will take an hour or so. When you are familiar with the work, it only takes 10 to 20 minutes.