Description And Function Of Components; Variable Cooking Control; Timer - Sharp R-771 OE Service Manual

VARIABLE COOKING CONTROL

The variable cooking control consists of the vari-motor,
vari-switch, gear, select lever bracket assembly, etc.
the purpose of the vari-motor is to rotate a cam which
is going to turn the vari-switch on and off within 30
seconds time base.
The vari-switch is operated ON by the cam lever and
cam which are linked to the vari-motor shaft. If the variable
LOW
MED. LOW (DEFROST)
MED.
MED. HIGH
HIGH

TIMER

Timer switch contacts:
The timer switch contacts are mechanically opened or
closed by turning the timer knob located on the timer
motor shaft.
These contacts control the current path
to the oven lamps and fan motor, etc.
Timer bell:
The bell striker is mechanically driven by the timer motor
and rings once at the end of the cook cycle.

DESCRIPTION AND FUNCTION OF COMPONENTS

ON
ON
9.8 Seconds I
ON
16.5 Seconds
ON
23.2 Seconds
ON
cooking control is set at LOW, MED. LOW, MED. or
MED. HIGH position, 240 volts A.C. is supplied to the
power transformer intermittently within a 30 seconds
time base. A half (l/2) of full power would be approx. 16
seconds of the switch on the 14 seconds of off time.
The following chart shows the vari-switch operation in
the various modes.
Microwave Power = Approx. 10%
OFF
(25 sec.)
Microwave Power = Approx. 30%
OFF
(20.2 sec.)
Microwave Power = Approx. 50%
OFF sec.)
Microwave Power = Approx. 70%
OFF (6.8 sec.)
Microwave Power = 100%
Timer motor:
Timer is dual speed type: cook time from 0 to 60 minutes
be selected. Up to 10 minutes the dial is divided in, 15
second intervals. From 10 minutes to 60 minutes the dial
is marked off in 5 minute intervals. The timer motor is
energized through the cook switch and therm0 cut-out
contacts. When the timer reaches the 0 point on the scale,
the timer switch opens the circuit to oven lamps, fan
motor, turntable motor, cook lamp, vari-motor and timer
motor, and the cook cycle stops.