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A Main Motor and Relay
Most of the dishwashers use 3450 RPM, 120V 60 Hz reversible type motor to drive the pump impellers
These motors utilize an external start relay and have two start or phase windings, a main or run winding and a
built-in overload protector
Direction of rotation of the armature or rotor is determined by the start winding selected through the timer
switch contacts See Figure 28
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FIGURE28
The relay is normally open with its coil connected in series with the main winding of the motor, and its switch con-
tacts connected in series with the motor slart winding (Since the relay is a gravity type device, it must be
mounted in an upright poshion ) See Figure 29.
BOTTOM OF RELAY
FIGURE29
When voltage is applied to the motor, as during the wash, rinse and drain periods of the dishwashing cycle, fi_e
momemary high current to the main winding energizes the relay solenoid The solenoid plunger is lifted, closing
the switch contacts The start winding is energized through the timer and relay contacts and the motor armature
begins to rotate_ As 1he motor approaches normal running speed, the current in the main winding, and in the
solenoid diminishes. When the current through the start relay drops below t0 amps the weight of the plunger
overcomes the weakening magnetic force of the solenoid coil and "drops out," disconnecting the motor start
winding
28