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Importance of Windscreen Wiper Motor Brushes in the Wiper Motor

Windscreen wiper motor brushes have played very important role in the construction of wiper motors. The motors used in windscreen wipers are also known as Ferrite magnet type motors as permanent magnets are used in them. These motors contain gears to control the speed of the wiper and three brushes to be used according to the speed of the wiper and the motor itself.

These three brushess include a high speed brush, a low speed brush and a common brush for the ground. The gear section of the wiper motor also contains a cam switch to stop the wiper every time at the same position.

In controlling the speed of the motor

The armature coils in the wiper motor generate a counter-electromotive force when it is turned to control the speed of rotation of the motor.

When low-speed brush from the three Windscreen wiper motor brushes provides current into the armature coils then they generate a large counter electromotive force to slow down the speed of rotation of the wiper motor.

But when high speed brush from the Windscreen wiper-motor brushes provides current to the armature coils then they generate a smaller force which allows the wiper motor to rotate at high speed.

In using cam switch

In order to stop wipers at a fixed position a system is used in the wiper motor known as Cam Switch. It allows the wipers stop at the bottom position of the windscreen after turning off the switch of wiper. This switch contains three contact pints along with a serrated cam plate.

The motor of your wiper operates when high or low current flowing through the Windscreen wiper-motor brushes passes through HI/Lo position of the wiper switch along with the voltage of car battery.

But when the switch of wiper is turned off even then sometimes wiper motor go on running. It happens due to 3 contact points on the cam plate. Suppose the second contact point is at other than serrated point then the voltage of battery will provide current to the wiper motor through Windscreen wiper motor brushes to let the contact point move from second to first point so that the wiper can stop at its fixed position by disconnecting the flow of current into the circuit almost instantly.

In this way, Windscreen wiper motor brushes play very important role in the construction as well as in the operation of the wiper motor.

Keywords in the article: Windscreen Wiper Motor, Horizontal Motor, Power Motor