Brush Holder, as an important component in the motor, acts as fixing the brush and guide its stable transmission between its stationary part and rotating part. And, its performance will directly affect overall motor efficiency and its service life. To overall evaluate its brush strength, its related parameters should ensure that the brush will not be transformed or damaged in the process of its motor operating.
- Spring Pressure:
The spring will offer constant pressure for the brush in order to keep an excellent contact with its rotating commutator or slip ring. The pressure of the spring should be suitable because its excessive pressure will speed up its frictional loss and the wear of the brush whereas its insufficient pressure will lead to inefficient contact and to generate the spark.
Electric Parameters
Electric parameters directly reflect the capacity and efficiency of the current transmission of the brush holder.
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Nominal Voltage can be defined as the highest voltage values of the brush that can be operated safely. That value must be higher than its actual operating voltage of the motor to ensure its insulating safety.
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Nominal Current can be defined as the maximum current that can be passed with a long term and stability. This parameter mainly depends on its section area and detailed material of the conductive board (or lead) because if the current is excessive, its conductive component will over heat even burn to totally damage.
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Contact Resistance can be defined as its contact-point resistance between the brush and the commutator. An excellent brush holder system should decrease its contact resistance furthest to reduce its energy loss and heat generation.
Circumstance Parameters
Circumstance Parameters can be defined as external condition scope of brush holder that can be normally operated.
- Working Temperature can be defined as its circumstance parameters of Brush Holder that can be normally operated. In the process of the motor, the heat will be generated. Therefore, the material of Brush Holder must keep its stable performances within this range of the temperature in order to aged-free, transformation-free or insulation reduction.
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Prevention Level can be presented as its IP Code in order to reflect dust-free and liquid-resistance of the Brush Holder. For example, in the circumstance of related moisture or dusty, its prevention level should be chosen a higher level for Brush Holder in order to prevent the dust and the water to infiltrate its internal, avoiding its insulation performance or jamming of the brush.
Generally speaking, complete technology index system includes the structure of brush holder, electric system and its operating circumstance. If designing and selecting brush holder, the designer must synthetically consider those parameters to ensure a matched overall performances for the motor, which can guarantee a safe, high-efficient and long-period for the operating of the motor.
