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Refer to the “WIRING DIAGRAM”
MICROWAVE COOKING
TIME COOKING
1. When the food is placed inside the oven and door is closed.
1) The low voltage transformer supplies the necessary voltage to the touch control circuit when the power cord is
plugged in.
2) The contacts of the interlock monitor switch open.
This switch creates short circuit to blow 15A fuse and stop magnetron oscillation when door is opened during
operation under abnormal condition (i.e. the contacts of the primary interlock switch do not open the circuit).
3) The contacts of the primary interlock switch close the primary circuit.
2. When cooking cycle, power and time are set by touching the function pads and the desired numerical pads.
1) The function indicating bar located on the digital light to indicate that the function have been set.
2) The time you set appears in the display window.
3) The touch control circuit memorizes the cooking program you set.
3. When the start pad is touched.
* The RELAY “1”, “2” are controlled by the touch control circuit.
1) 220VAC is applied to the high voltage transformer through the contacts of RELAY “1” (Fig. 1)
2) Fan motor starts rotating and cools the magnetron by blowing the air coming from the intake on the rear plate hole.
3) The oven lamp light the inside of the oven.
4) Indicator light turns on to indicate function operation. Cooking time starts count down.
5) 3.3 Volts AC is generated from the filament winding of the high voltage transformer. This filament voltage is applied to
the magnetron to heat the magnetron filament through two noise preventing choke coils.
6) A high voltage of 2000 Volts AC is generated in the secondary of high voltage transformer and this secondary voltage
is increased by the action of the diode and the charging of the high voltage capacitor. This resultant DC voltage is then
applied to the anode of the magnetron. As shown in Fig. 2 the first half cycle of the high voltage produced in the high
voltage transformer secondary charges the high voltage capacitor. Current flow is in the direction of the dotted-line
during the second half cycle, the voltage produced by the transformer secondary, and the charge of the high voltage
capacitor are combined and applied to the magnetron as shown by the solid line so that oscillations begin. The
disturbance wave generated by the magnetron is prevented by the choke coils of 3.2µH, filter capacitors of 16pF and
the magnetron’s shielded case so that TV and radio programs are not impaired by noise.
CIRCUIT DESCRIPTION
