SOI 12.06 FV
11/43
599 37 42-75
OPERATION SEQUENCE
OFF CONDITION
Closing the door activates the monitored latch switch and the stop switch.
IMPORTANT
When the oven door is closed, the contacts COM - NC of the monitored switch must be open.
When the microwave oven is plugged in a wall outlet (230V / 50Hz), the line voltage is supplied to the noise
filter.
( Figure O-1 )
1. The control unit is not energized. The display shows nothing (Fig. O-1 (a)).
2. Open the door. The contacts (COM-NC) of the monitored latch switch are closed and the control unit is
energized. Then contacts of relays RY1 and RY5 are closed, and the oven lamp will light and the display will
show "SELECT LANGUAGE" in 5 languages. (Fig. O-1(b)).
NOTE: Once the language is selected using the LANGUAGE key, the display will show "ENERGY
SAVE MODE TO GO OUT OF ENERGY SAVE MODE SET CLOCK" when the oven is plugged in.
3. Close the door. The contacts (COM-NC) of the monitored latch switch are opened and the contacts of
relay
RY1 are opened and the oven lamp will be turned off. The display will show " . 0". (Fig. O-1(c)).
NOTE: Energy save mode
1. If the oven has not been used for more than 3 minutes, the contacts of the relay RY5 will be opened and the
control unit will be not energized. Open and close the door, the control unit will resume.
2. If the clock is set, this energy save mode does not work.
3. If the display shows different messages from
ENERGY SAVE MODE,
the oven may be set in demo mode.
Close the door, see operation manual to cancel demo mode.
MICROWAVE COOKING CONDITION
HIGH COOKING
Enter a desired cooking time by touching the TIME keys and start the oven by touching START key.
Function sequence (Figure O-2)
CONNECTED COMPONENTS
RELAY
Oven lamp, Turntable motor
RY1
Power transformer
RY3
Fan motor
RY6
1. The line voltage is supplied to the primary winding of the high voltage transformer. The voltage is converted to
about 3.3 volts A.C. output on the filament winding and high voltage of approximately 2000 volts A.C. on the
secondary
winding.
2. The filament winding voltage (3.3 volts) heats the magnetron filament and the high voltage (2000 volts) is sent
to the voltage doubling circuit, where it is doubled to negative voltage of approximately 4000 volts D.C..
3. The 2450 MHz microwave energy produced in the magnetron generates a wavelength 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 single tone is heard and the relays RY1 + RY3 + RY6 go back to their
home position. The circuits to the oven lamp, high voltage transformer, fan motor and turntable motor are cut
off.
5. When the door is opened during a cook cycle, the switches come to the following condition.
CONDITION
SWITCH
CONTACT
DURING
COOKING
DOOR OPEN
(NO COOKING)
COM-NO
Closed
Opened
Monitored latch switch
COM-NC Opened Closed
Stop switch
COM-NO
Closed
Open
COM-NO
Closed
Opened
Monitor switch
COM-NC
Opened
Closed
The circuits to the high voltage transformer is cut off when the contacts of relay RY2, and the contacts (COM-NO) of
the monitored latch switch SW1 and the monitor switch SW3 are made open. The circuit to the fan motor is cut off
when the relay RY6 is made open.
