I doubt this can happen with a modern machine, but I was sewing sail-cloth on my old trusty 1926 Singer machine.
I know better than to try using a modern machine to sew Velcro onto sail-cloth!
Finally finished the job, re-spooled three empty spools and thought longingly of a cup of coffee, but when I took my foot of the peddle ,Mrs Singer just soldiered on!
Obviously, I disconnected the machine from the power supply and went and drank my coffee, then re-connected sewing machine. Same problem!
If this happens to you, check the peddle first. A pin had lodged itself between the button you press down on, on these old models and the side of the opening the button moves up and down in, thus creating the illusion that I was still trying to sew, or a continuous circuit I suppose is what an electrician would call it.
If this happens to you, don't panic.
Disconnect the power source and pull the plug out of the socket on the motor.
Find an old-fashioned screwdriver for screws that predate all the fancy headed modern screws, and unscrew the back plate of the peddle. The pin will then fall out. all on its own.
You may have to break off the rubber pads that Singer thoughtfully placed round the screws to prevent them scratching a floor. I had to, and not surprisingly in the course of the last 97½ years those rubber pads had turned rock hard and prevented my getting anywhere near the screws as long as they were in position.
Fasten the back plate into position again, and your trusty old sewing-machine will run as if she had just come off the assembly line.
How I blessed the old seamstress who told me, some forty years ago, that her sewing machine had played this trick on her, all because of a pin that had gone somewhere it shouldn't have.
