I just finished testing five extra sewing machine motors I have.
I got two of them used but in good shape from the LSMG, and three of them from Miriam.
As far as pics go, I’m sorry I didn’t take any before or during pics, only after pics.
The two motors from the LSMG, an Alpha Sew and a silver Brother were in great shape and needed nothing. They were complete with cords, plugs and brackets.
The blue Brother was seized up from lack of oil and had rust and mold inside. It was seized up when I got it, but the rust and mold came from when my basement flooded last June. The wiring was rotted and crumbled off with a touch. The bearings were so dry that even when I had been oiling the oil holes every day for nearly a month the oil had not soaked through the bearings. They were that dry. It took lots of cleaning to get the motor clean enough to rewire.
The black Montgomery Wards had been disassembled in an attempt to use some of its parts to fix another motor as its cord was bad. It was fairly clean inside. When the other motor would not be fixed the parts were reclaimed to make this motor a good one. I also used the bracket from the other motor to complete this one.
This motor gave me fits as I worked on it. One tiny field to brush wire broke and I had to replace it. There was also some verdigris on some of the wires and insulation that was difficult to clean off.
And the solder did not want to join the old wire to the new.
The insulation on the large field wires just crumbled away, so when I was able to solder the new wire to the old wire I had to use liquid tape to completely insulate the wires at the field coil. There was just no way to get the heat shrink tubing up close enough so it would cover all the wire as it shrank.
The silver Japanese motor was very clean and didn’t really need repaired, however someone had cut the wires off about 1 ½” from the body. Since there was some length of wire I decided to splice in a piece instead of disassembling the motor and doing a complete rewire.
When the new wire was spliced in and heat shrinked the silver motor ran good but smoked a bit like my blue clone, and got HOT! Much too hot for the little amount I sewed with it.
What I think happened with it is I used the wire from Sew-Classic that is miss marked and not 18-2, more like 20-2. (I did a thread on this some time back, don’t remember the title though.) I'm fairly sure there was an amperage drop with the lighter gauge wire that caused the motor to heat up.
Last week my wife was running errands and stopped at a local place that sells wire and bought some correct 18-2 SPT-1 wire from them. It's too late to send the wrong wire back to S-C.
I finished rewiring the motor yesterday and tested it today.
No problems now. The motor got a bit warmer than when cold, that's normal, but it did not get hot.
As a test I did nothing different to the motor. I simply unsoldered the lighter gauge wire and soldered in the correct gauge wire. I even used the same plug, cord block and foot controller.
I used Rusty to test the motors.
He was rough and cranky at first. I've been using him as a HC machine since I got the HC unit. After about the second motor he began to really smooth up and quiet down.
I'm thinking I just might put a motor on him and leave it. He's a good e-machine. Sews quiet and smooth.
Now some tips.
>ALWAYS wire the motor with the same gauge wire that the factory used. As I described above it does make a difference.
>Always check the actual wire diameter in the replacement cord you buy. The problem cord I bought IS marked 18-2 SPT-1 but the wire is NOT 18 gauge. Perhaps it’s 20 gauge, I don’t know as I don’t have any proven 20 ga to compare it with.
>Always try to identify the neutral side of the motor, either by the plug if it’s polarized, or the markings on the old cord, or the color of the field to brush wires. It can make a difference even though the motor isn’t polarized.
>If you are sure you have all your wiring insulated, and there isn’t any shorts, but you still get a buzz from the motor, unplug it, rotate the plug 180° and plug it back in. That matches up the polarity of the motor to the electrical source and in every case I’ve gotten a buzz, it’s stopped it.
>Don’t worry about over oiling an old motor. The two I totally disassembled were literally dry as a bone. The sintered metal (maybe bronze) shaft bushings were so dry I had to soak them in oil to get them to soak it up. Merely using the tiny oil hole in the housing wasn’t getting it done.
>I use denatured alcohol to clean my fingers and the electrical wires before I splice and solder them. The alcohol removes the oils from the wires and my fingers and helps the solder to fuse to the wire.
Refurbishing and re-wiring motors isn’t difficult or complicated, you just have to pay attention to what you are doing.