Sharp Carousel R-980E Instrukcja serwisowa - Strona 6

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R-980E

The following is a description of component functions

during oven operation.

Relay and Components Connection

RELAY

CONNECTED COMPONENT

RY1

Oven lamp/ Turntable motor

RY2

Power transformer

RY3

Convection heater

RY4

Damper motor

RY5

Convection motor

RY6

Fan motor

OFF CONDITION

Closing the door activates all door interlock switches:

upper latch switch, lower latch switch and stop switch. (In

this condition, the monitor switch contacts are closed.)

When oven is plugged in a wall outlet (230 - 240V, 50Hz),

rated voltage is supplied to the control unit. (Figure O-1):

1. The display flashes "SHARP", "MICRO-", "WAVE",

'OVEN".

To set any programmes or set the clock, you must first

touch the STOP/CLEAR pad.

" : " appears in the display and the time counts up

every minute.

NOTE: When the oven door is opened, the oven lamp

comes on at this time.

2. A signal is input to the control unit, energizing the coil

of shut-off relay (RY4).

RY4 contacts close, completing a circuit to the damper

motor. The damper motor now operates moving the

damper to the open position, thereby closing the

contacts of damper switch inputs a signal to the control

unit.

The coil of relay RY4 is de-energized, opening its

contacts, thereby turning off the damper motor.

MICROWAVE COOKING CONDITION

HIGH COOKING

Enter cooking time by pressing the NUMBER pads and

then select microwave cooking and power level by press-

ing the POWER LEVEL pad. When the START pad is

touched, the following operations occur:

1. The contacts of relays are closed and components

connected to relays are turned on (RY1, RY2, RY6).

(Figure O-2)

2. Rated voltage is supplied to the primary winding of the

power transformer. The voltage is converted to about

3.3 volts A.C. output on the filament winding and high

voltage of approximately 2260 volts A.C. on the high

voltage winding.

3. The filament winding voltage (3.3 volts) heats the

magnetron filament and the high voltage (2260 volts) is

sent to the voltage doubling circuit.

4 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.

OPERATION SEQUENCE

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, the

monitor switch, upper latch switch, lower latch switch

and stop switch are activated with the following results.

The circuits to the turntable motor, cooling fan motor

and high voltage components are de-energized, the

oven lamp remains on 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 upper latch switch and lower latch

switch and is mechanically associated with the door so

that it will function in the following sequence.

1) When the door opens from a closed potion, the upper

latch switch and the lower latch 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 upper latch switch and lower latch switch must be

closed.

If the common and normal open contacts of upper latch

switch and the lower latch switch fail with their contacts

closed when the door is opened, the closing of the monitor

switch contacts will form a short circuit through the fuse,

upper latch switch and the lower latch switch, causing the

monitor fuse to blow.

MEDIUM HIGH, MEDIUM, MEDIUM LOW, LOW

COOKING

When variable cooking power is programmed, the rated

voltage is supplied to the power transformer intermittently

through the contacts of the relay (RY2) which is operated

by the control unit within a 32-second time base. Micro-

wave power operation is follows:

VARI MODE

HIGH (100% power)

MED HIGH (approx. 70% power)

MED (approx. 50% power)

MED LOW (approx. 30% power)

LOW (approx. 10% power)

NOTE: The ON/OFF time ratio does not exactly correspond

CONVECTION COOKING CONDITION

PREHEATING CONDITION

Press the PREHEAT pad and then select preheating

temperature by pressing the temperature pad. When the

START pad is touched, the following operations occur:

1. The coil of shut-off relays RY1+RY5+RY6 are

energized, the oven lamp, cooling fan motor, turntable

motor and convection motor are turned on.

2. The coil of relay (RY4) is energized by the CPU unit.

The damper is moved to the closed position, opening

the damper switch contacts. The opening of the damper

switch contacts sends a signal to the LSI on the CPU

to the percentage of microwave power, because

approx. 2 seconds are needed for heating up the

magnetron filament.

ON TIME

OFF TIME

32 sec.

0 sec.

24 sec.

8 sec.

18 sec.

14sec.

12 sec.

20 sec.

6 sec.

26 sec.