5 – 1
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CHAPTER 5.
OPERATION SEQUENCE
[1] OFF CONDITION
Closing the door activates all door interlock switches (1st. latch switch
and 2nd. interlock relay control switch).
MPORTANT
When the oven door is closed, the monitor switch contacts (COM-NC)
must be open. When the microwave oven is plugged in a wall outlet,
rated voltage is supplied to the noise filter and the control unit.
Figure O-1 on page 14-1
1. The display shows "MICRO-", "WAVE" and "OVEN".
2. To set any programmes or set the clock, you must first touch the
STOP/CLEAR pad.
3. " . 0" appears in the display.
NOTE: When the oven door is opened, the oven lamp comes on at
this time.
[2] MICROWAVE COOKING CONDITION
1. HIGH COOKING
Enter a desired cooking time with the touching NUMBER pad and start
the oven with touching START pad.
Function sequence
Figure O-2 on page 14-1
1. The rated voltage is supplied to the inverter unit.
2. The inverter unit converts the rated voltage into high-voltage and
high frequency current. And the inverter unit drives the magnetron.
3. The 2450 MHz microwave energy produced in the magnetron gen-
erates a wave length of 12.24 cm. This energy is channelled
through the waveguide (transport channel) into the oven cavity,
where the food is placed to be cooked.
4. When the cooking time is up, a signal tone is heard and the relays
(RY1+RY2) go back to their home position. The circuits to the oven
lamp, inverter unit and turntable motor are cut off. The fan motor
will operate for one minute after cooking.
5. When the door is opened during a cook cycle, the switches come to
the following condition
The circuits to the inverter unit and turntable motor are cut off when the
1st. latch switch and 2nd. interlock relay control switch are made open.
The oven lamp remains on even if the oven door is opened after the
cooking cycle has been interrupted, because the relay RY1 stays
closed. Shown in the display is the remaining time. The fan motor will
operate for one minute after cooking.
6. MONITOR SWITCH CIRCUIT
The monitor switch is mechanically controlled by oven door, and
monitors the operation of the 1st. latch switch and 2nd. interlock
relay.
1) When the oven door is opened during or after the cycle of a
cooking program, the 1st. latch switch and 2nd. interlock relay
control switch must open their contacts first. After that the con-
tacts (COM-NC) of the monitor switch can be closed.
2) When the oven door is closed, the contacts (COM-NC) of the
monitor switch must be opened. After that the contacts of the
1st. latch switch and 2nd. interlock relay control switch are
closed.
3) When the oven door is opened and the contacts of the 1st. latch
switch and 2nd. interlock relay remain closed. The fuse F10A
will blow, because the monitor switch is closed and a short cir-
cuit is caused.
2. VARIABLE OUTPUT POWER COOKING
There are present eleven (11) microwave power levels. When the
microwave oven is preset for variable cooking power, the output power
of the magnetron is varied according to variable frequency which is
generated from the inverter unit.
[3] SENSOR COOKING CONDITION
Using the SENSOR function, the food is cooked without figuring time,
power level or quantity. When the oven senses enough steam from the
food, it relays the information to its microprocessor which will calculate
the remaining cooking time and power level needed for best results.
When the food is cooked, water vapor is developed. The sensor
“senses” the vapor and its resistance increases gradually. When the
resistance reaches the value set according to the menu, supplemen-
tary cooking is started. The time of supplementary cooking is deter-
mined by experiment with each food category and inputted into the
LSI.
An example of how sensor works: (JACKET POTATOES)
1. Potatoes at room temperature. Vapor is emitted very slowly.
2. Heat potatoes. Moisture and humidity is emitted rapidly. You can
smell the aroma as it cooks.;
3. Sensor detects moisture and humidity and calculates cooking time
and variable power.
CONNECTED COMPONENTS
RELAY
Oven lamp, Turntable motor
RY1
2
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CONDITION
SWITCH CONTACT
DURING
COOKING
DOOR OPEN
(NO COOKING)
1st. latch switch
COM-NO
Closed
Open
2nd. interlock relay
control switch
COM-NO Closed
Open
Monitor switch
COM-NC
Open
Closed
MICROWAVE
MICROWAVE
HUMIDITY SENSOR
R-350Y(S)
