Basic Description

Fig. 1 Compound wound rectangular windshield wiper motor. Shown w/washer pump installed:

Fig. 2 Rectangular windshield wiper motor electrical connections:

Description:
The rectangular motor, Fig. 1, consists of an armature, brush plate assembly, field coils and a housing which is attached to a gear housing. The motor electrical connections, park switch, and on some models a washer pump are also mounted on the gear box. A gear on the commutator end of the armature drives an intermediate gear and pinion assembly, which in turn drives the output shaft. A crank arm on the output shaft operates wipers through a pivot link (transmission) assembly.

Operation:
When ignition is on, battery voltage is supplied to motor terminal 2, Fig. 2. Current flows through the series field to a splice where it is divided, and part passes through the armature and part through the shunt field. The armature and shunt field circuits are completed to ground through the wiper switch, with motor speeds determined by resistance in the shunt field ground path.