Sharp R-880F User Manual

4
R-880F(S)
OPERATION SEQUENCE
OFF CONDITION
Closing the door activates the 1st. latch switch and 2nd.
interlock relay control switch.
IMPORTANT:
When the oven door is closed, the contacts COM-NC
of the monitor switch must be open. When the mi-
crowave oven is plugged in a wall outlet (230 - 240V
50Hz), the line voltage is supplied to the noise filter
and the control unit.
Figure O-1 on page 33
1. The oven display will show " SHARP MICRO- WAVE
OVEN " .
2. Press the STOP/CLEAR pad. The oven display will
show " : ".
3. Set the clock as follows.
3-1. Press the CLOCK pad once.
3-2. Enter the time of day by perssing the number
pads.
3-3. Start the clock by pressing the CLOCK pad.
NOTE:
1. If you do not set the clock, " : " will appear on the
display. When the operation of the oven is finished, " :
" will appear on the display instead of the time of day.
2. The oven can be also used when the clock is not set.
3. When the oven door is opened, the oven lamp does not
come on.
MICROWAVE COOKING CONDITION
100% (HIGH) COOKING
Enter a desired cooking time by pressing the number pads
and start the oven by pressing START pad.
Function sequence Figure O-2 on page 33
CONNECTED COMPONENTS RELAY
Convection motor RY1
High voltage transformer RY2
Grill heater (Top) RY3
Bottom heater RY4
Fan motor, RY5
Oven lamp, Turntable motor RY6
1. The line voltage is supplied to the primary winding of
the high voltage transformer. The voltage is converted
to about 3.3 volts A.C. output on the filament winding
and high voltage of approximately 2000 volts A.C. on
the secondary winding.
2. The filament winding voltage (3.3 volts) heats the
magnetron filament and the high voltage (2000 volts) is
sent to the voltage doubling circuit, where it is doubled
to negative voltage of approximately 4000 volts D.C..
3. The 2450 MHz microwave energy produced in the
magnetron generates a wave length of 12.24 cm. This
energy is channelled through the waveguide (transport
channel) into the oven cavity, where the food is placed
to be cooked.
4. When the cooking time is up, a signal tone is heard and
the relays RY2 + RY5 + RY6 go back to their home
position. The circuits to the oven lamp, high voltage
transformer, fan motor and turntable motor are cut off.
5. When the oven door is opened during a cooking cycle,
the switches come to the following condition.
Switch Contact Condition
During Oven Door
Cooking Open(No cooking)
1st. latch switch COM-NO Closed Opened
2nd. interlock relay
control switch
COM-NO Closed Opened
Monitor Switch COM-NC Opened Closed
The circuit to the high voltage transformer, fan motor, oven
lamp and turntable motor are cut off when the 1st. latch
switch and 2nd. interlock relay control switch are made
open. Shown in the display is remaining time.
6. MONITOR SWITCH CIRCUIT
The monitor switch is mechanically controlled by the
oven door, and monitors the operation of the 1st. latch
switch and the 2nd. interlock relay RY2.
6-1. When the oven door is opened during or after the
cycle of a cooking program, the 1st. latch switch and
2nd. interlock relay control switch must open their
contacts first. After that the contacts (
COM-NC) of the
monitor switch can be closed.
6-2. When the oven door is closed, the contacts (COM-
NC) of the monitor switch must be opened. After that
the contacts of the 1st. latch switch and 2nd. interlock
relay control switch are closed.
6-3. When the oven door is opened and the contacts of the
1st. latch switch and 2nd. interlock relay RY2 remain
closed, the fuse F10A will blow, because the monitor
switch is closed and a short circuit is caused.
70% (MEDIUM HIGH), 50% (MEDIUM), 30% (ME-
DIUM LOW), 10% (LOW COOKING)
When the microwave oven is preset for variable cooking
power, the line voltage is supplied to the high voltage
transformer intermittently within a 32-second time base
through the relay contact which is coupled with the cur-
rent-limiting relay RY2. The following levels of microwave
power are given.
SETTING
Note: The On/Off time ratio does not exactly correspond
to the percentage of microwave power, because
approx. 3 seconds are needed for heating up the
magnetron filament.
GRILL COOKING CONDITIONS
The oven has three grill cooking condition. They are the
TOP HEATER mode, BOTTOM HEATER mode and TOP
AND BOTTOM HEATER mode.
TOP HEATER MODE
In this mode, the food is cooked by the top heaters. Press
the GRILL pad once and then enter the cooking time by
pressing the number pads. When the START pad is
pressed, the following operations occur:
Figure O-3(a) on page 34
100%
32 sec. ON
70%
Approx. 70%
100%
24 sec. ON 8 sec. OFF
14 sec. OFF
20 sec. OFF
26 sec. OFF
50% Approx. 50%
18 sec. ON
30%
Approx. 30%
12 sec. ON
10% Approx. 10%
6 sec. ON

Sharp R-880F Specifications

General

Brand	Sharp
Model	R-880F
Category	Microwave Oven
Language	English