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7. The solid-state relays are energized (if the cavity temperature
is lower than the selected temperature) and the main supply
voltage is applied to the heating elements to return to the
selected cooking temperature.
8. Upon completion of the cooking time, the audible signal will
sound, and oven lamp, turntable motor, cooling fan motor and jet
motor are de-energized. At the end of the convection cycle, if the
cavity air temperature is above 230˚F, the circuit to RY5 will be
maintained (by the thermistor circuit) to continue operation of the
cooling fan motor until the temperature drops below 195˚F, at
which time the relay will be de-energized, turning off the fan
motor. Relay RY3 will however, open as soon as the convection
cycle has ended, turning off the convection fan motor.
SPEED BAKE COOKING
Touch SELECTA PROGRAM pad 8 times and touch SET pad.
Then touch SET pad to select desired temperature. Enter cooking
time. When the START pad is touched, the following operations
occur: (Figure O-3)
1. The contacts of the relays RY1, RY3 and RY5 are closed, and
the oven lamp, turntable motor, jet motor and fan motors are
energized.
NOTE : The rotate direction of the jet motor is the same as one of
the convection cooking.
2. The solid-state relays are energized and the main supply
voltage is applied to the top and side heating elements.
NOTE : After cooking, the operation of the fan motors is the
same as one of the convection cooking.
HIGH SPEED GRILL/ SPEED GRILL COOKING
Touch SELECTA PROGRAM pad 6 times and touch SET pad.
Enter cooking time. When the START pad is touched, the following
operations occur: (Figure O-4)
1. The contacts of the relays RY1, RY3, RY5 and RY6 are closed,
and the oven lamp, turntable motor, jet motor and fan motors
are energized.
NOTE : The rotate direction of the jet motor is reverse to one
of the convection cooking by the relay RY6.
2. The solid-state relays are energized and the main supply
voltage is applied to the top and side heating elements.
NOTE : After cooking, the operation of the fan motors is the
same as one of the convection cooking.
HIGH SPEED GRILL WITH MICRO/ SPEED GRILL
WITH MICRO/ SPEED ROAST COOKING
Touch SELECTA PROGRAM pad 9 times and touch SET pad.
Then touch SET pad to select desired temperature. Enter cooking
time. When the START pad is touched, the following operations
occur: (Figure O-5)
1. The contacts of the relays RY1, RY3 and RY5 are closed, and
the oven lamp, turntable motor, jet motor and fan motors are
energized.
NOTE : The rotate direction of the jet motor is the same as one
of the convection cooking for the first time. But for the
last 15 minutes, the direction is reverse by the relay
RY6.
2. The solid-state relays and relay RY2 are energized alternately,
and the main supply voltage is applied to the top and side
heating elements and the power transformer alternately.
NOTE : After cooking, the operation of the fan motors is the
same as one of the convection cooking.
AUTOMATIC COOKING
Automatic cooking will automatically compute the oven tempera-
ture, microwave power and cooking time. And the oven will cook
according to the special cooking sequence.
FIRE SENSING FEATURE (MICROWAVE MODE)
This model incorporates a sensing feature which will stop the
oven's operation if there is a fire in the oven cavity during micro-
wave cooking. This fire sensing feature will operate when the
microwave power level is set to 80% or more. This is accomplished
by the LSI repeatedly measuring the voltage across the tempera-
ture measurement circuit (thermistor) during it's 32-seconds time
base comparing the obtained voltage measurements. If the most
recent voltage measured is 300 mV greater than the previous
voltage measured, the LSI judges it as a fire in the oven cavity and
switches off the relays to the power transformer, fan motor and jet
motor. The LSI also stops counting down and closes the damper
door so that no fresh air will enter the oven cavity. Please refer to
the following section for a more detailed description.
Operation
Please refer to the timing diagrams below.
1. The fire sensing will start after 5 minutes when the oven is
started.
2. The thermistor operates within a 32-seconds time base and it
is energized for three (3) seconds and off for 29 seconds. Two
(2) seconds after the thermistor is energized, the voltage
across the temperature measurement circuit is sampled by the
LSI and twenty five (25) seconds after the thermistor is cut off
the LSI turns on the convection fan for three (3) seconds.
3. The above procedure is repeated. If the difference between the
first voltage measured (in step 1) and the voltage measured
when the procedure is repeated (step 2) is greater than 300 mV
the LSI makes the judgment that there is a fire in the oven cavity
and will switch off the relays to the power transformer, fan motor
and jet motor. The LSI also stops counting down and closes the
damper door so that no fresh air will enter the oven cavity.
4. Once the fire sensor feature has shut the unit down, the
programmed cooking cycle may be resumed by pressing the
"START" pad or the unit may be reset by pressing the "CLEAR"
pad.
0 2 3
28
ON
JET MOTOR
OFF
3 sec.
THERMISTOR
ON
OFF
ON
Sensing
Voltage
OFF
Sensing the voltage across temperature measurement circuit.
FAN MOTOR OPERATION
After cooking is completed, the fan motors will continue for 1
minute. At the end of the cooking cycle, if the cavity air temperature
is above 230˚F, the circuit to RY5 will be maintained (by the
thermistor circuit) to continue operation of the cooling fan motor until
the temperature drops below 195˚F, at which time the relay will be de-
energized, turning off the fan motor.
7
31 32 (sec.)
64 (sec.)
3 sec.
R-8000G
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