Electrolux E30MO65GSSB, Technical & Service Manual

Page: 18 / 64

Operation
2-6
The relationship between the convection and microwave
power operations are as follows.
Compu Broil/ Compu Roast/
Compu Bake
COMPU BROIL/ ROAST/ BAKE will automatically
compute the oven temperature, microwave power and
cooking time for baking, roasting and broiling. Set the
desired program by touching the COMPU BROIL/
ROAST/ BAKE pad, and NUMBER pad. Enter the weight
by touching the NUMBER pads. When the START pad is
touched, the following operations occur:
1. The COOK indicator will light and the Convection Fan
Symbol will rotate.
2. The cooking time will appear on the display and start
counting down to zero. The cooking time is adjusted
automatically according to the weight of the food.
3. The shut-off relays (RY1, RY5 and RY6) are
energized, turning on the oven lamp, turntable motor,
cooling fan motor and convection motor. The power
supply voltage is applied to the heating element.
4. Now, the oven is in the convection cooking mode.
5. When the oven temperature has reached the
programmed convection temperature, the oven goes
into the programmed cooking mode.
6. At the end of the COMPU BROIL/ ROAST/ BAKE
cycle, the damper is returned to the open position
and the oven will go to the off condition. The cooling
fan will remain on until the oven has cooled.
Compu Defrost Cooking
The COMPU DEFROST key is a special function key to
defrost meats and poultry faster and better. When the
COMPU DEFROST is selected and the food weight is
entered by using the COMPU DEFROST pad, 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 ovens’ operation if there is a fire in the oven cavity
during microwave cooking. This is accomplished by the
LSI repeatedly measuring the voltage across the
temperature measurement circuit (thermistor) during its’
32-seconds time base comparing the obtained voltage
measurements. If the most recent voltage measured is
300mV 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
convection motor. The LSI also stops counting down and
closes the damper door so that no fresh air will enter the
oven cavity.
Operation
Please refer to the timing diagrams on next page.
1. 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 one (21) seconds after the thermistor is cut off
the LSI turns on the cooling fan for six (6) seconds.
The ON/OFF time ratio does not correspond with
the percentage of microwave power, because
approx. 2 seconds are needed for heating of the
magnetron filament.
During alternate Microwave/Convection operation,
the convection heater is energized only if the cavity
temperature drops below the set temperature.