Reasons for Abnormal Noise of Miniature DC Geared Motors

The reasons for the abnormal noise of the miniature DC gear motor are roughly divided into: foreign objects in the motor, bearing damage, cracking of the dynamic balance glue, etc. We can analyze it from the following points:

Point 1: Whether the structural parts are loose can be judged by whether the armature moves axially and causes a collision.

The second point: connect the power supply of the motor electronic control system to the oscilloscope to see if the waveform is missing a wave head. Vibration and noise may occur during phase loss.

The third point: whether the compensation coil and the armature lead are reversed.

The fourth point: whether the spacer on the magnetic pole is still there, because it will affect the performance and running state of the DC motor.

Fifth point: electromagnetic noise problem. , you can turn the motor to the rated speed to see if it is within a certain range, and then cut off the power supply (the armature and the excitation are cut off at the same time) to see if there is still a process during the deceleration process. If not, it can be determined to be electromagnetic noise.

The causes of electromagnetic noise are:

1) The lengths of the stator and rotor do not match (too much difference).

2) The stator and rotor slots are not properly matched, and the iron core laminations are not tight

3) The inclination of the rotor slot is not enough.

4) Radial vibration of the rotor core.

5) Wrong winding pitch.

6) The cage bars of the cage rotor are welded or disconnected.

7) The coil of a certain pole phase group is reversed.

8) Voltage and frequency vary greatly. The voltage is seriously unbalanced and the frequency is too high, causing the electromagnetic sound to increase.

9) There is a branch circuit breakage in the parallel winding, and the stator winding is asymmetrical or short-circuited between turns.

The sixth point: The mechanical aspect may be lack of oil in the bearing, wear of the end cover, grinding of the fan blade, etc.

Damaged or poorly assembled bearings. When the motor rotates, place one end of the listening rod on the bearing end cover and the other end on the earlobe. Use your fingers to listen to the sound of the bearing rotating evenly and whether there is a periodic "click" sound. If there is any abnormal sound , It means that there is a problem with the bearing, which is generally caused by a serious lack of oil in the bearing, impurities in the oil, unqualified product quality or bearing wear.

The above points can basically find out the reason for the abnormal noise of the micro DC geared motor. Usually pay attention to maintenance, try to avoid the occurrence of various problems. The normal operation of the motor is also a great guarantee for the safety of users.