Stepping Motor Driver Fault and Elimination Method
Abstract: Stepper motor drive principle is the operation of a stepper motor to have an electronic device to drive, this device is stepper motor driver,it converts pulse signal which output by control system into stepper motor angular displacement.Or to say: each pulse signal is generated by the control system,through stepper drive to make stepper motor rotate one step angle. So the speed of the stepper motor is proportional to the frequency of the pulse signal. Stepper motor drive failure, it will affect the normal use of stepper motor,we use some examples to illustrate the stepper motor driver troubleshooting in the following.
Once the stepper motor driver start, the drive external fuse is burned and the device can not run. After maintenance staff do inspection, find a power tube has been damaged, but without information of this components, can not figure out the role of the tube,think it is front push of power-driven,change a power tube, power on, the fuse is burned again,and the tube is also damaged.Checked by the maintenance engineer, the initial analysis is correct, that is,fuse burned again,the drive must have an abnormal high current, and check out a power tube damaged. But do not clear of the role of the tube. In fact the tube is stepper motor power drive tube, stepper motor is high-voltage start,so it need to bear high voltage and high current. Static check, find the pulse loop distributor line, the power to the ground side resistance is very small,but there is no short circuit. According to the number of components in the line and its power consumption analysis,the power to the ground side of the resistance should not be so small, so suspected there are components have been damaged in circuit.
Power on check,find a chip abnormal heat. Power off,cut off the chip's power pin, static check,it is normal of the increasing resistance from power to ground. Measured the chip's power to the ground resistance is very small. Check the chip model, a non-standard models,do not find in manuals. By circuit analysis, confirm that it is the main component in the board: ring pulse distributor.
For further confirmation the problem of the chip, first change a voltage resistance and current power equivalent to the stepper motor power drive tube,restore the chip's power pin, with a light-emitting diode circuit instead of stepping motor winding as the simulation load. After power on, the light-emitting diodes are bright, that is,the windings are energized, which is not meet the circuit requirements.Input the step pulse,there is no response, so confirm the chip is damaged. But market do not have this chip,in the case of the drive cover space allowing,aplly for combination circuit, that is,use the d flip-flop and the combination of non-gate design of a ring pulse generator,produced on a small print System board, remove the original chip,and install the small printed circuit board through the pin on the original chip pad. Still use the light-emitting diode for analog load, after power on,step pulse bright followed by sequential order. Remove the analog load, access the host, power on, equipment normally operate.