6
R - 1 8 7 0
R - 1 8 7 1
OPERATION
DESCRIPTION OF OPERATING SEQUENCE
The following is a description of component functions
during oven operation.
OFF CONDITION
Closing the door activates the door sensing switch and
secondary interlock switch. (In this condition, the monitor
switch contacts are opened.)
When oven is plugged in, 120 volts A.C. is supplied to the
control unit. (Figure O-1).
1. The display will show SHARP, SIMPLY, THE, BEST,
PRESS, CLEAR, and PRESS, CLOCK.
To set any program or set the clock, you must first touch
the STOP/CLEAR pad. The display will clear, and " : "
will appear.
COOKING CONDITION
Program desired cooking time touching the NUMBER
pads. When the START pad is touched, the following
operations occur:
1. The contacts of relays are closed and components
connected to the relays are turned on as follows.
(For details, refer to Figure O-2)
RELAY
CONNECTED COMPONENTS
RY1
Oven lamp
RY2
Power transformer/ Stirrer motor
RY4
Turntable motor
RY5
Fan motor
2. 120 volts A.C. is supplied to the primary winding of the
power transformer and is converted to about 3.3 volts A.C.
output on the filament winding, and approximately 2000
volts A.C. on the high voltage winding.
3. The filament winding voltage heats the magnetron filament
and the H.V. winding voltage is sent to a voltage doubler
circuit.
4. The microwave energy produced by the magnetron is
channelled through the waveguide into the cavity feed-
box, and then into the cavity where the food is placed to
be cooked.
5. Upon completion of the cooking time, the power
transformer, oven lamp, etc. are turned off, and the
generation of microwave energy is stopped. The oven will
revert to the OFF condition.
6. When the door is opened during a cook cycle, monitor
switch, door sensing switch, primary switch and secondary
switch and secondary interlock relay are activated with
the following results. The circuits to the stirrer motor, the
cooling fan motor, the turntable motor, and the high
voltage components are de-energized, and the digital
read-out displays the time still remaining in the cook cycle
when the door was opened.
7. The monitor switch is electrically monitoring the operation
of the primary and secondary switch and secondary
interlock relay and is mechanically associated with the
door so that it will function in the following sequence.
(1) When the door opens from a closed position, the
secondary interlock relay, door sensing switch, primary
and secondary switch open their contacts, and then
the monitor switch contacts close.
(2) When the door is closed from the open position, the
monitor switch contacts first open, and then the
contacts of the primary and secondary switch close.
If the primary switch, secondary switch and secondary
interlock relay fail with their contacts closed when the door
is opened, the closing of the monitor switch contacts will
form a short circuit through the monitor fuse, secondary
switch switch, primary switch and secondary interlock
relay, causing the monitor fuse to blow.
POWER LEVEL P-0 TO P-90 COOKING
When Variable Cooking Power is programmed, the 120
volts A.C. is supplied to the power transformer
intermittently through the contacts of relay (RY2) which is
operated by the control unit within an interval second time
base. Microwave power operation is as follows:
VARI-MODE
ON TIME
OFF TIME
Power 10(P-HI)
32 sec.
0 sec.
(100% power)
Power 9(P-90)
30 sec.
2 sec.
(approx. 90% power)
Power 8(P-80)
26 sec.
6 sec.
(approx. 80% power)
Power 7(P-70)
24 sec.
8 sec.
(approx. 70% power)
Power 6(P-60)
22 sec.
10 sec.
(approx. 60% power)
Power 5(P-50)
18 sec.
14 sec.
(approx. 50% power)
Power 4(P-40)
16 sec.
16 sec.
(approx. 40% power)
Power 3(P-30)
12 sec.
20 sec.
(approx. 30% power)
Power 2(P-20)
8 sec.
24 sec.
(approx. 20% power)
Power 1(P-10)
6 sec.
26 sec.
(approx. 10% power)
Power 0(P-0)
0 sec.
32 sec.
(0% power)
Note: The ON/OFF time ratio does not correspond with the
percentage of microwave power, because approx. 2
seconds are needed for heating of the magnetron
filament.
Summary of Contents for Carousel R-1870
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