There are many types of DC servo motors, which can be divided into many types according to different methods. The editor also introduced them one by one last time. However, when DC servo motors are widely used, there are some unavoidable faults. When encountering these faults, we need to know how to repair them. Therefore, in practice, we need to have advanced repair knowledge. The following is an introduction to some common faults and causes of DC servo motors.
DC servo motors are mainly used as actuator drives in various digital control systems and power drives that require accurate control of stable speed or accurate control of speed change curves. It is easy to control, sensitive, quick to respond, can output larger power, simplifies the mechanical transmission structure, and is easy to maintain. Therefore, it is widely used in CNC machine tools.
1. Brake failure.
Most motors used on vertical axes are equipped with brakes. When the brake fails, it will cause overcurrent, overheating and other malfunctions in the motor.
When repairing a motor with a brake, the brake should be disengaged . The common method is to directly connect the power supply to the brake coil to disengage it. For example, it is more convenient to have a mechanical release device. Some brakes have rectifiers, which should be checked if there is a problem.
2. The motor vibrates when it rotates. There are several reasons:
1. There is a short circuit in the commutator.
2. The surface of the commutator is burned out and uneven.
3. Oil has penetrated into the brush or there is oil stain on the surface of the commutator.
3. Overcurrent and overload. When a DC servo motor used normally on a machine tool suddenly experiences this failure, there are some reasons:
1. The motor brushes and other parts are short-circuited to ground or poorly insulated.
2. The output power components and related parts of the controller are faulty.
3. Excessive mechanical load is caused by mechanical reasons. It will not affect the motor after troubleshooting. However, the motor often runs under overcurrent conditions, which may cause damage to the motor.
4. The torque decreases and becomes weak. An alarm will sound if there is slight resistance. The reasons for this type of failure are as follows:
1. The motor may be demagnetized.
2. The brush contact resistance is too large or the contact is poor.
3. The brush spring is burned out, causing the pressure to become smaller, resulting in excessive sparks under the brush.
4. The controller is faulty.
5. The DC servo motor rotates with noise or abnormal sound. The reasons are:
1. The commutator is rough or singed.
2. There is foreign matter in the motor or the magnet has become detached.
3. The mechanical connection part is incorrectly installed.
4. Bearing damage or other mechanical failure.
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