Galanz WP700AP20 - Door Interlock Switch

fuse main latch switch
—-—f
Si
pilot switch\ §
3
S2
door closed assistant latch switch
(a)
Fig. 2-5
door hook
latch switch
pilot switch
2.4.1 DOORINTERLOCK SWITCH
Drawing 2-5(a) is the circuit and construction diagram
of the door interlock switch of brand, EMN-109
microwave oven. It mainly consists of latch switch (S1,
S2), pilot switch (S3), door hook and starting
mechanism of the door interlock switch.
There fixed hooks on the oven door, and opened two
rectangle hole at the corresponding place at the right of
the oven and the hook. Inside each rectangle hole,
there fixed a micro switch. When the oven door closed,
the two hook on it would insert into the rectangle hole,
and just push down several micro switches. At that time,
S1, S2 arę closed, S3 is cut off, and the microwave
oven is under preparation of working. To that
mechanical control microwave oven, no sooner you
turn the time switch to set the heating time than the
power would be supplied to the back to start the oven.
To those touch control microwave oven, hardly do you
set the heating time and power, and touch the start
button when the power would supplied to the back to
start the oven. When press down the door release
button, S1, S2 arę cut off, S3 is closed, and the
microwave oven would stop operating immediately.
Provided due to some mań - madę or the appliance
itself reasons, when the door is open, S1, S2 arę
closed, due to the pilot switch (S3) still at conducted
condition would mąkę the 220V voltage short-circuited
and fused the fuse, and will never let the microwave
oven working when the door is open. From this we can
understand the function of the interlock switch is when
the door is unclosed, the oven wouldn't work, when the
door is opened when the oven is working, it would stop
the working immediately (FIG.2-5b).
2.4.2 TIME AND POWER DISTRIBUTOR
Time and power distributor is mainly composed of timer
motor and two sets of gear switch S4 and S5. When
the timer is at zero position, the gear switches arę cut
off, when the heating time is settled, the gear switch is
closed. When started the oven, the time motor starts
working. When it reaches the settled time, it would cut
off the gear switch (s4) to step the oven working. The
gear switch (S5) is designed for controlling the output
of the microwave oven, actually for controlling the
output of the magnetron. It mainly by the method which
mąkę the magnetron working internally at the same
working point to change the output of the magnetron.
This method was called "CONDUCTION RATIO
CONTROL". But there is another method which is
called "ELECTRIC LEVEL CONTROL" which is
through changing the working point (such as anodę
voltage or magnetic field) to change the output of the
Fig
2-6
magnetron. Because of conduction ratio control
method is Iow cost, high function and high reliability, it is widely used for those microwave oven which have the
door release button
Fig. 2-5 (b)
timer & power motor
l
220V
transformer
6