3-1

PRODUCT OPERATION

SYSTEM OVERVIEW

ELECTRONICS

The functions of controlling the motor and the
user interface console are combined into a
single 16-bit micro controller on the main circuit
board.
The micro controller also controls a
transformerless 85 watt switchmode power
supply. The power supply uses a large drop-
ping resistor on the heater plate and phase
control of the line voltage to produce a variable
voltage supply. The micro controller can sup-
ply 5 - 85 volts to the various components.
The user interface has a circuit board for front
controls and a touch switch panel for internal
controls.

MOTOR & HALL SENSOR

The electronically controlled 80V, 60w, 3 phase,
4-pole, brushless DC motor runs at 2300-2850
rpm during wash cycles, and approximately
4200 rpm during drain.
The hall sensor is mounted on a small circuit
board clipped to the motor case, and monitors
motor speed and rotation.

HEATER PLATE

The heater plate is a porcelain enameled steel
plate that supports the motor at the base of the
tub and is clamped in place by a lock ring nut.
A thick film resistive circuit for the heater ele-
ment and the power supply dropping resistor
are printed on the dry side of the heater plate.
The heater element is only activated during
wash cycles. It is not used for drying. Tempera-
ture is maintained by the thermistor. Overheat
protection is provided by a thermal fuse located
on the heater plate.

AMOUNT OF WATER

The tub fills with 0.8 gallons of water, approxi-
mately level with the base of the spray arm.
Once this level is reached, the wash is primed
to pump water through the spray arm, which
will then rotate.
The load on the wash pump is constantly
monitored throughout the wash cycle and the
water level adjusted if necessary.

TUB HOME SENSOR

Using an infrared transmitter and receiver
mounted on the controller circuit board, the tub
home sensor detects when the tub is closed
and ready to start a cycle.
The transmitter sends infrared light through an
optical light pipe to the side of the tub. Another
optical light pipe leads from the infrared re-
ceiver to the side of the tub. When the tub is
closed, the two light pipes are optically con-
nected via a prism mounted in the side of the
chassis.

DETERGENT/RINSE AID

DISPENSER

The detergent/rinse aid dispenser door is
opened manually to load detergent, and then
manually closed to transport the detergent to
the tub by the inlet water. An electronically-
controlled inlet water diverter valve enables
each detergent chamber to be dispensed sepa-
rately.
A positive displacement pump and storage
tank is incorporated within the dispenser to
supply rinse agent. The electronic controller
regulates the amount of rinse agent dispensed.
A red light on the tank filler cap indicates an
empty rinse agent tank.