Why Is The Spark Of The Micro DC Motor Too Large?

The frictional contact between the carbon brushes and the commutator is unavoidable when the micro DC motor is running. It is normal that the constant friction will produce weak sparks. If the sparks of the carbon brushes are too large, the wear will be accelerated, and the rotor will be burned in severe cases. So what is the cause of the excessive spark of the micromotor, and what should the motor do when it encounters this situation?

1) The carbon brush of the micro DC motor is too hard or does not meet the requirements. This problem can be solved by using the carbon brush that meets the requirements;

2) The pressure of the micro-motor carbon brush holder is uneven, and the pressure of the carbon brush can be balanced by adjusting the spring pressure appropriately;

3) The carbon brush holder is loose, and the brush holder bolts are fixed so that the brush holder and the commutator are parallel;

4) The distance between the brush holder and the surface of the commutator is too large, adjust the distance from the brush holder to the commutator, generally 1~3mm;

5) Poor contact between the carbon brush and the commutator may be caused by the failure of the carbon brush. Replace the carbon brush with a new one or grind the contact surface of the carbon brush;

6) The carbon brush and the brush holder are not properly matched, and the two should not be too tight or too loose to ensure that the brush can slide freely in the brush holder when it is hot. If it is too loose, a new carbon brush needs to be replaced;

7) The center position of the carbon brush holder is wrong, just move the carbon brush holder;

8) The commutation pole coil is short-circuited, and the coil is re-wound;

9) The armature winding is short-circuited, disassemble the motor, check the armature winding, and use a millivolt meter to find the open circuit. If it cannot be welded, rewind it, or replace it with a new armature.

If none of the above problems are true, it may be that the bearing is worn and the starting current is large; the contact area between the carbon brush and the rotor is small, the pressure of the carbon brush is small, and it is not fully contacted with the rotor.

If the spark is too large, don't panic, follow the above reasons to eliminate the cause of the motor's excessive spark step by step and solve it.