Lesson 4/Learning Event 3
Electric windshield wipers are the most popular type for use on modern automotive equipment.
Electric windshield wipers operate at a constant, easily controlled speed, making them much more
desirable than their vacuum counterparts. One of the drawbacks to using electric windshield wipers
in early automotive equipment was the heavy electric current requirements that their motor placed
on the vehicle's 6-volt electrical system. This problem was solved as 12-volt electrical systems
became standard. The electric wiper motor, through a worm gear, drives a shaft that is connected
to a crank. The circular motion of this crank is transformed into reciprocating motion by the wiper
transmission to operate the wiper arms. In addition to the control switch that is used to control the
windshield wipers, a separate, mechanically operated park switch also is incorporated into the
motor. The purpose of this switch is to provide power to the wiper motor long enough to return
the wiper arms and blades to a retracted position whenever they are switched off by the operator.