DC motor troubleshooting - Database & Sql Blog Articles

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1. The motor speed becomes slower, and the cause of the fault of the playback may occur in the electronic speed stabilization device and the motor itself. If there is no problem with the power supply, most of the motors are faulty. Repairs can be made by replacing the new motor with the motor. The repair of the motor is mainly to repair the brush, because the brush is prone to wear and tear.
2. The motor does not turn (the internal motor is good) The motor does not turn to the fault phenomenon, but the power supply voltage is connected to the inner motor and the operation is normal, so it can be determined that the electronic steady speed circuit is faulty. Because the adjustment transistor in the electronic steady-state circuit is damaged, an open circuit phenomenon is caused, and the motor does not rotate. Amplifying transistors in a steady-state circuit sometimes cause this failure as well.
3, the motor speed is too fast, and can not adjust the speed. This fault is mostly due to the short circuit of the adjustment transistor in the electronic steady speed circuit, so that the voltage across the motor increases close to the power supply voltage, the motor speed greatly exceeds the rated speed, adjusted Speed ​​potentiometer, the speed does not change.
4. The rotation speed is basically normal, but the reason why the rotation speed is unstable with the change of the power supply voltage is due to the failure of the electronic stability circuit, which is most likely caused by transistor breakdown. This breakdown is also different from the short circuit. The collector and the emitter of the transistor are equivalent to a linear resistance. When the applied voltage changes, the voltage is directly applied to both ends of the motor, so that the motor speed also changes. The same happens if the magnification of the transistor drops a lot.
5, the speed of the unstable motor with the speed is sometimes normal, and sometimes the phenomenon of instability, often due to poor contact with the trimmer potentiometer. Such potentiometers tend to be oxidized after a long period of use, causing poor contact, sometimes breaking or breaking, or causing instability of the belt speed due to changes in resistance.
6. The rotation speed oscillates, the current shakes uncertainly. Sometimes the motor runs normally, and the speed can be adjusted. However, after the load is applied, the rotation speed oscillates. If the current meter is used to detect the motor current, there is jitter. This may be caused by a fault in the regulation of the steady state of the load, and the resistance value becomes large, causing the positive feedback amount to be excessive. When repairing, replace the qualified resistor or use two resistors in parallel to make it more reliable.