Maybe your motor is spinning too fast.

It is also possible that your motor torque is too high, especially the starting torque. There are many reasons for jumping wires. If it is not because the car is too thick and the needle is broken and changed, then clean up the sundries of the thread feeder and shuttle bed of the sewing machine, and then change the needle on the oil truck. There is also to check whether the number of stitches matches the cloth. There is also the phenomenon that the thread feeder is too tight, which will also cause needle jumping. If the above situation cannot be improved, that is, the ordinary cotton and knitting in your car are jumping, then it is necessary to consider whether the needle bar position is high.