Ok, the wife has a long-arm quilting machine. The machine is basically a large-throated sewing machine meant to sew quilt tops to the backs with a layer of padding sandwiched between. Fairly powerful machine.
She's starting to have what we think is an electrical issue.
The machine includes incandescent lights, a motor, and some solid-state hardware of course.
The repair company is in Northern Ohio though she prefers to deal with the Michigan repair facility. To get the machine to Michigan (or Ohio for that matter) will cost a lot of money and time whether we drive or ship it.
The machine has worked flawlessly for years.
The symptom that started last week was that after a few minutes of usage, the motor would stall or stop. Cycling the power on the machine would allow the machine to continue for a few more minutes, then it would happen again. There's a start-stop switch on the operator's grip, but this would not bring the machine back - only a real power cycle would do it.
This intermittency seems to be heat related, though I could not find anything hot on the machine. That is, first thing in the morning, it would run for a while, then the failures would begin, and become more and more frequent.
Yesterday as per the repair shop (via phone support) I replaced a transformer. The new one is rated about 2.5 times the power of the old one. Since the replacement, the machine has halted once, after a much longer time than has been the norm lately.
But it still halted. So while the transformer may have played a role, it isn't the culprit, or it created a secondary problem.
Is the motor failing? It's a 90v dc model. Could the previous under-sized transformer have damaged the motor, and now the new transformer is doing what it should, but it's too late?
Of course the motor speed is controlled by a computer circuit, so if that circuit is failing all bets are off.
An incandescent light electrically attached to machine does not flicker when this happens.
What causes a DC motor to stop?