DC motor commutator sparks

the principle of commutation spark division to maintain the brush and commutator in good working condition, to maintain excellent commutation performance is an important condition to ensure the safety of DC motor.

Under normal circumstances, the motor runs without spark (or runs under weak harmless spark), the oxide film on the surface of the commutator is uniform and shiny, and the brush and commutator wear are slight, etc., which can be considered as good commutation performance. On the contrary, strong commutation spark, commutator surface oxide film damage or abnormal, the sliding contact between the brush and the commutator is unstable, the brush and the commutator abnormal wear and so on are the symptoms of poor commutation, will directly threaten the motor operation.

spark is the arc discharge phenomenon between the brush and the commutator, which is the most obvious sign of poor commutation of DC motor.

Due to the slight brush spark release energy is weak, it will not constitute a hazard to the operation of the motor, so it is called harmless spark. Strong brush sparks will destroy the sliding contact between the brush and the commutator, burn the brush mirror and the commutator surface oxide film, increase the wear of the two, and cause a vicious circle. This kind of spark is harmful Spark.

what's more, due to the strong brush sparks, the air on the brush mill is free, and the ring fire accident caused by the arc overflight causes great damage to the motor, which poses a threat to the operation of the DC motor. Different commutation sparks have different effects and hazards on the operation of DC motors. In order to determine the effects and hazards of commutation sparks on the operation of DC motors, spark levels must be divided. The commutation spark is the amount of electromagnetic magnetic released in the commutation element when the brush and the commutator are out of contact, which is manifested in the form of arc discharge.

According to the commutation spark research shows that it is a broad spectrum of electromagnetic waves, the main range of the spectrum is 30KHZ to 1MHZ. The harmfulness of commutation spark should be based on the sign of spark energy, which can be used as a standard for evaluating commutation spark. However, because of the complexity and difficulty of spark measurement, spark brightness, density and size are usually used as the basis for dividing spark grade. The classification criteria for sparks vary from country to country, but all of these criteria are based on the brightness, intensity, size, and damage to brushes and commutators.

of the commutation spark level, since there is no instrument that can accurately measure the commutation spark level, it is determined by the observer's visual, so it is inevitable to have some subjective factors of the spark observer.