Combination Cooking - Panasonic NN-L750WB Service Manual

3. When the temperature drops below the predetermined
temperature, the digital programmer circuit supplies power to
power relay RY5 resulting in the convection heater turning on.
Note: After the convection process, if the oven temperature is
higher than the predetermined temperature, the fan motor rotates
to cool the electronic components and the oven.

7.5. Combination Cooking

Combination cooking is achieved by operating the microwave and heater modes together
during one cooking cycle. There are three combination modes.
1. Combination (convection and microwave)
2. Combination (grill and microwave)
3. Combination (grill, convection and microwave)
The digital programmer circuit operators the power relays as shown in the figures below.
When the oven temperature reaches the predetermined temperature, the digital programmer
circuit stops supplying power to relay (RY5) resulting in the convection heater turning off.
During this time the digital programmer circuit continues to operate relay (RY1) so that
microwave activity continues at the duty cycle selected. The inverter control signal level is also
maintained. The microwave activity continues to cycle until the entire cooking program is
completed.
When the oven temperature drops below the selected temperature, the digital programmer
circuit operates power relay (RY5) switching on the heater elements.
In the case of grill combination the sequence applies with the digital programmer circuit
Figure1
Convection Cooking Duty Cycles
32