Description Of Operating Sequence - Panasonic NN-E251W Service Manual

4. DESCRIPTION OF OPERATING SEQUENCE

4.1 Variable power cooking control
The coil of power relay B(RY 1) is energized intermittently
by the digital programmer circuit, when the oven is set at
any power selection except for high power position. the digi-
tal programmer circuit controls the ON-OFF time of power
relay B contacts in order to vary the output power of the
microwave oven from "Warm" to "High" power. One com-
plete ON and OFF cycle of power relay B is 29 seconds.
The relation between indications on the control panel and
the output of the microwave oven is as shown in the table.
NOTE: The ON/OFF time ratio does not correspond with
the percentage of microwave power since
approximately 2 seconds are required for heat-
ing of magnetron filament.
4.2 Cyclic defrost
When defrost power and defrosting time is selected and
start pad is touched:
1. The digital programmer circuit (DPC) divides the total
defrosting time into 5 periods, consisting of 3 defrosting
periods, each followed by a standing period except last
defrosting.
2. During 1st defrosting power periods, power relay B ener-
gized for 17 seconds and de-energized for 12 seconds by
DPC.
3. During 2ND and LAST defrosting power periods, power
relay B energized for 14 seconds and de-energized for
15 seconds by DPC.
4. During standing periods, power relay B energized for 5
seconds and de-energized for 24 seconds by DPC.
NOTE: Defrosting time selected is converted into cer-
tain percent by the DPC but the display will
show selected time in minutes and seconds as
programmed. The total number of seconds is
divided into 5 different periods.
Example #2: If Defrosting time is selected for 10 minutes,
each operationg period will be as follows:
10minutes = 600seconds, 600/100 = 6seconds(1%)
20% - 20% -
(120sec.) - (120sec.) -
(2min.) - (2min.) -
4.3 Auto defrost, auto reheat cook control
When the auto control feature is selected and start pad is
touched:
1. The digital programmer circuit determines the power level
and cooking time to complete cooking and indicates the
operating state in the display window. The table shows
the corresponding cooking times for respective serving
by categories.
2. When cooking time in the display window has elapsed,
the oven turns off automatically by a control signal from
the digital programmer circuit.
10% - 40% - 10%
(60sec.) - (240sec.) - (60sec.)
(1min.) - (4min.) - (1min.)
POWER OUTPUT
SETTING POWER
APPROX.
HIGH 800W
LOW 470W
WARM 140W
CYCLIC 250W
DEFROST
AUTO DEFROST
CATEGORY
1.BREAD
2. MEAT
AUTO REHEAT
CATEGORY
1. REHEAT
2. JACKET POTATO
3. FROZEN VEG.
6
ON TIME OF OFF TIME OF
POWER RELAY B POWER RELAY B
ON(SEC) OFF(SEC)
29
17
5
Please refer to
description of cyclic defrost
WEIGHT TOTAL
DEFROSTING
TIME
80g 0m 40s
180g 3m 54s
WEIGHT COOKING TIME
300g 4m 00s
400g 8m 00s
500g 10m 00s
0
12
24