Panasonic NN-ST340M - Microwave Operating Sequences and Controls; Variable Power Control (NN-SM Models); Variable Power Control (NN-ST Models); Auto Controls (NN-ST Models)

4.1. Variable power cooking
control (NN-SM330M, SM330W,
SM320M)
The vari-power controller controls the ON-OFF time of the vari-
power switch to vary the output power of the microwave oven
from “Low” to “High”. The vari-power controller is a part of the
timer assembly. The timer assembly consists of timer motor,
timer switch, vari-power switch and the combination of gears,
cam and actuater level.
One complete cycle of the vari-power controller is 30 senconds,
in which the vari-power switch is turned “ON” or “OFF” by the
cam rotation in the 30 ± 2 second period.
By controlling the timing of the vari-power switch “ON” period,
the 220 or 240V AC supplied to the high voltage transformer is
interrupted intermittently so that the average output power of
the microwave oven is varied.
Table shows the timing chart of vari-power switch operation in
response to the power setting on the control panel.
NOTE:
The ON/OFF time ratio does not correspond with the
percentage of microwave power since approximately 2
seconds are required for heating of magnetron
filament.
Variable Power Cooking
OUTPUT ON-OFF TIME OF
POWER SETTING POWER(%) POWER RELAY B (RY1)
APPROX. ON(SEC) OFF(SEC)
HIGH 100% 30 0
MEDIUM-HIGH 80% 23.2 6.8
MEDIUM 55% 16.5 13.5
DEFROST 35% 9.8 20.2
LOW 15% 5 25
4.2. Variable power cooking
control (NN-ST340M, ST340W)
The coil of power relay B (RY1) is energized intermittently by
the digital programmer circuit, when the oven is set at any
power selection except for High power position. The digital
programmer circuit controls the ON-OFF time of power relay B
contacts in order to vary the output power of the microwave
oven from ”Low” to “High” power. One complete ON and OFF
cycle of power relay B is 22 seconds. The relation between
indications on the control panel and the output of the
microwave oven is as shown in table.
NOTE:
The ON/OFF time ratio does not correspond with the
percentage of microwave power since approximately 2
seconds are required for heating of magnetron
filament.
OUTPUT ON-OFF TIME OF
POWER SETTING POWER(%) POWER RELAY B (RY1)
APPROX. ON(SEC) OFF(SEC)
HIGH 100% 22 0
MEDIUM-HIGH 70% 17 5
MEDIUM 50% 13 9
DEFROST 30% 8 14
LOW 15% 5 17
4.3. Turbo Defrost, Auto Reheat,
Auto Cook control (NN-
ST340M, ST340W)
When those Auto Control feature is selected and the Start Pad
is tapped:
1. The digital programmer circuit determines the power level
and cooking time to complete cooking and indicates the
operating state in the display window.
Table shows the corresponding cooking times for
respective serving or weight 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.
Turbo Defrost
WEIGHT SELECTED COOKING TIME
1.0KG 14 min.30 sec.
Auto Reheat
WEIGHT SELECTED COOKING TIME
200g 2 min.00 sec.
Auto Cook
CATEGORY WEIGHT SELECTED COOKING TIME
Vegetables 250g 4 min.00 sec.
4 DESCRIPTION OF OPERATING SEQUENCE
8
NN-ST340M / NN-ST340W / NN-SM330M / NN-SM330W / NN-SM320M