Sharp Carousel R-880FS Service Manual - Page 11

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FUSE F10A 250V

1. If the wire harness or electrical components are short-

circuited, this fuse blows to prevent an electric shock or

fire hazard.

2. This fuse blows when the 1st. latch switch and 2nd.

interlock relay (RY2) remain closed with the oven door

open and when the contacts (COM-NC) of monitor

switch closes.

FUSE 15A

If the wire harness or electrical components are short-

circuited, this fuse blows to prevent an electric shock or fire

hazard.

HIGH VOLTAGE FUSE

The high voltage fuse blows when the high voltage rectifier

or the magnetron is shorted.

THERMAL CUT-OUT 125˚C (MG)

This thermal cut-out protects the magnetron against over-

heating. If the temperature goes up higher than 125˚C

because the fan motor is interrupted or the ventilation

openings are blocked, the thermal cut-out will open and

line voltages to the high voltage transformer will be cut off

and the operation of the magnetron will be stopped.

THERMAL CUT-OUT170˚C (OVEN)

The thermal cut-out located on the top of the oven cavity

is designed to prevent damage to the oven if the foods in

the oven catch fire due to over heating produced by

improper setting of the cooking time or failure of control

unit. Under the normal operation, the oven thermal cut-out

remains closed. However, when abnormally high tem-

perature are reached within the oven cavity, oven thermal

cut-out will open at 170˚C causing the oven to shut down.

The thermal cut-out will cut back in at 155˚C.

THERMISTOR

The thermistor is a negative temperature coefficient type.

The temperature in the oven cavity is detected through the

resistance of the thermistor, and then the control unit

causes the heating element relay to operate, thus the

current to the heating element is turned ON/OFF.

TURNTABLE MOTOR

The turntable motor drives the turntable roller assembly to

rotate the turntable.

FAN MOTOR

The fan motor drives a blade which draws external cool air.

This cool air is directed through the air vanes surrounding

the magnetron and cools the magnetron. This air is chan-

nelled through the oven cavity to remove steam and

vapours given off from heating food. It is then exhausted

through the exhausting air vents of the oven cavity.

CONVECTION MOTOR

The convection motor drives the convection fan and

provides the heated air.

NOISE FILTER

The noise filter assembly prevents radio frequency inter-

ference that might flow back in the power circuit.

TOP HEATERS

The top heaters are located on the top of the oven cavity

assembly. The top heaters send out heat to grill foods.

BOTTOM HEATER

The bottom heater is located on the floor of the oven cavity

assembly. The bottom heater sends out heat to grill foods.

ONVECTION COOKING SYSTEM

This oven is designed with a hot air heating system where

food is not directly heated by the top and bottom heaters,

but is heated by forced circulation of the hot air produced

by the top and bottom heaters. The air heated by the top

and bottom heaters is circulated through the convection

passage provided on the outer casing of the oven cavity by

means of the convection fan which is driven by the

convection motor. It then enters the inside of the oven

through the vent holes provided on the left side of the oven.

Next, the hot air heats the food on the turntable and leaves

the oven cavity through the vent in the oven cavity left side

wall. Without leaving the oven, this hot air is reheated by

the top and bottom heaters, passes through the convec-

tion passage and enters the inside of the oven cavity

again, in a continuing cycle. In this way, the hot air

circulates inside the oven cavity to raise its temperature

and, at the same time, comes into contact with the food

being cooked. When the temperature inside the oven

cavity reaches the selected temperature, the top and

bottom heaters are de-energized. When the temperature

inside the oven cavity drops below the selected tempera-

ture, the top and bottom heaters are energized again. In

this way, the inside of the oven cavity is maintained at

approximately the selected temperature. When the con-

vection time reaches 0, the top and bottom heaters are de-

energized and the convection fan stops operating and the

oven shuts off. Upon completion of the cooking time, the

audible signal will sound, and oven lamp, turntable motor,

cooling fan motor and convection motor are de-energized.

At the end of the convection cycle, if the cavity air tempera-

ture is above 120˚C, the circuit to RY5 will be maintained

(by the thermistor circuit) to continue operation of the

cooling fan motor until the temperature drops below 104˚C,

at which time the relay will be de-energized, turning off the

fan motor. Relay RY1 will however, open as soon as the

convection cycle has ended, turning off the convection fan

motor. This will now cool.

R-880F(S)