Read Panasonic NN-SD381SZPE / NN-SD361MZPE Service Manual online
4.1. Variable power cooking
control
High Voltage Inverter Power Supply (U) controls output power
by the signal from Digital Programmer Circuit (DPC). Power
relay always stay on, but PWM (Pulse Width Modulation) signal
controls microwave output power.
NOTE:
by the signal from Digital Programmer Circuit (DPC). Power
relay always stay on, but PWM (Pulse Width Modulation) signal
controls microwave output power.
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.
percentage of microwave power since approximately 2
seconds are required for heating of magnetron
filament.
Variable Power Cooking
POWER SETTING
OUTPUT
POWER(%)
APPROX.
MANUAL MICROWAVE
DUTY
ON(Sec.)
OFF(Sec.)
HIGH
100%
22
0
MEDIUM-HIGH
65%
22
0
MEDIUM
50%
22
0
MEDIUM-LOW
30%
22
0
DEFROST
30%
14
8
LOW
20%
13
9
4.2. Inverter power supply circuit
The Inverter Power Supply circuit powered from the line
voltage, 220V 50Hz AC input supplies 4,000V DC to the
magnetron tube, and functions in place ofthe H.V. transformer,
the H.V. capacitor and H.V. diode.
1. The AC input voltage 220V 50Hz is rectified to DC voltage
voltage, 220V 50Hz AC input supplies 4,000V DC to the
magnetron tube, and functions in place ofthe H.V. transformer,
the H.V. capacitor and H.V. diode.
1. The AC input voltage 220V 50Hz is rectified to DC voltage
immediately.
2. DC voltage will be supplied to the switching devices called
IGBT. These devices are switched ON-OFF by the 20 to 40
kHz PWM (pulse width modulation) signal from the
microcomputer in the DPC.
kHz PWM (pulse width modulation) signal from the
microcomputer in the DPC.
3. This drives the High voltage transformer to increase voltage
up to 2,000V AC.
4. Then the half-wave doubler voltage rectifier circuit,
consisting of the H.V. diodes and capacitors, generates the
necessary 4,000V DC needed for the magnetron.
necessary 4,000V DC needed for the magnetron.
5. Output power of the magnetron tube is always monitored by
the signal output from the current transformer built into the
inverter circuit.
inverter circuit.
6. This signal is fed back to the microcomputer in the DPC to
determine operating conditions and output necessary to
control PWM signal to the Inverter Power Supply for control
of the output power.
control PWM signal to the Inverter Power Supply for control
of the output power.
4.3. Turbo defrost, Auto cook
When the Auto Control feature is selected and the [Start] pad
is tapped:
1. The digital programer circuit determines the power level and
is tapped:
1. The digital programer circuit determines the power level and
cooking time to complete cooking and indicates the
operating state in the display window.
operating state in the display window.
2. When cooking time in the display window has elapsed, the
oven turns off automatically by a control signal from the
digital programmer circuit.
digital programmer circuit.
Turbo Defrost
WEIGHT SELECTED
COOKING TIME
1.0KG
13min. 10sec.
Auto Reheat(Meal)
WEIGHT SELECTED
COOKING TIME
800g
8min. 00sec.
4 DESCRIPTION OF OPERATING SEQUENCE
7
NN-SD381S / NN-SD361M
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