Sharp R-210A 用户手册

4

7-1. When the oven door is opened during or after the

cycle of a cooking program, the 1st latch switch and
2nd latch switch must open their (COM-NO) contacts
first. After that the contacts (COM-NC) of the monitor
switch can be closed.

7-2. When the oven door is closed. The contacts (COM-

NC) of the monitor switch must be opened and the
contacts (COM-NO) of the 2nd latch switch and the
1st latch switch must be closed.

7-3. When the oven door is opened and the (COM-NO)

contacts of the 1st latch switch and the contacts
(COM-NO) of the 2nd latch switch remain closed, the
fuse 13A will blow, the monitor switch is closed and a
short circuit is caused.

When the microwave oven is preset for variable cooking
power, the rated voltage is supplied to the power trans-
former intermittently within a 30-second time base through
the vari switch. The following levels of microwave power
are given.

HIGH

30 sec. ON

MEDIUM HIGH

Approx. 70%

Approx. 100%

23.2 sec. ON

6.8 sec. OFF

13.5 sec. OFF

20.2 sec. OFF

MEDIUM

Approx. 50%

16.5 sec. ON

MEDIUM LOW

Approx. 30%

9.8 sec. ON

25 sec. OFF

LOW

Approx. 10%

5.0 sec. ON

Note:

The ON/OFF time ratio does not exactly corre-
spond to the percentage of microwave power,
because approx. 2 seconds are needed for heat-
ing up the magnetron filament.

1. When the timer knob is at " 0 ", the oven is OFF

condition.

2. Closing the oven door activates the 1st latch switch, the

2nd latch switch and monitor switch.

IMPORTANT:
When the oven door is closed, the contacts COM-NC of
the monitor switch must be open.

HIGH COOKING
Set the variable cooking control to HIGH and then set the
timer.

1. Following components are energized.

Power transformer

H.V. capacitor

Timer motor

Magnetron

H.V. rectifier

Fan motor

H. V. fuse

Turntable motor

Oven lamp

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 2000 volts A.C. on the sec-
ondary winding.

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

magnetron filament and the high voltage (2000 volts) is
sent to the voltagedoubling circuit, where it is doubled
to negative voltage of approximately 4000 volts D.C..

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.

5. When the cooking time is up, the timer returns to "0",

the bell rings and the contacts of the timer are opened.
Then following components are turned off.

Power transformer

Magnetron

Timer motor

Turntable motor

H.V. capacitor

Fan motor

H. V. fuse

H.V. rectifier

Oven lamp

6. When the oven door is opened during a cooking cycle,

the switches come to the following positions and they
are common to the other cooking conditions too.

Switch

Contact

Condition

During

Oven Door

Cooking

Open(No cooking)

1st latch Switch

COM-NO

Closed

Opened

Monitor Switch

COM-NC

Opened

Closed

2nd latch switch

COM-NO

Closed

Opened

The circuit to the power transformer, turntable motor,
timer motor, fan motor and oven lamp are cut off when
the COM-NO contacts of the 2nd latch switch and 1st
latch switch are made open. The timer stops to indicate
how much cooking time remains.

7. MONITOR SWITCH CIRCUIT

The monitor switch is mechanically controlled by the
oven door, and monitors the operation of the 1st latch
switch and 2nd latch switch.

SETTING