Stepper Motor Repair

Stepper motor malfunctions typically manifest as one or more phases of the windings burning out (short circuit or open circuit). This type of fault can be diagnosed by measuring the DC resistance of the motor's coils with a multimeter and comparing it to the resistance of a normal coil (in most cases, the motor coils will not burn out simultaneously; one or more groups will be intact). This helps determine if the motor coils are burnt out. For motors secured with screws, a screwdriver and pliers can be used to directly disassemble them. If the casing is welded in, a file or hacksaw must be carefully used to pry it open, being careful not to pry it forcefully to avoid deformation. After disassembly, the internal structure of the motor can be seen. If one or two phases of the motor coil are burnt out, as long as the coil frame is not deformed, you can rewind it yourself according to the original coil and number of turns. (When disassembling the burnt coil, be sure to count the number of turns and measure the wire diameter of the removed coil with a micrometer. Because the thickness of the enameled wire is different between imported and domestic wire, you need to use a gas lighter to burn off the enamel before measuring. The same method should be used to measure the substitute wire.) If the frame is deformed, the frame must be replaced. If a suitable frame cannot be found, a similar frame must be used for modification. Alternatively, you can make your own using high-temperature resistant, flame-retardant insulating material and glue it together to make it the same shape as the original frame. After winding, carefully install it together. Rotate the motor shaft by hand; there should be no obvious jamming. It should be noted that if the stepper motor is damaged, the stepper motor drive circuit should also be checked for damage before replacing the stepper motor.