Sharp r-8580 manual Convection Heater, Convection Cooking System, Damper OPEN-CLOSE Mechanism

R-8580

CONVECTION HEATER

The convection heater is located at the left side of the oven cavity. It is intended to heat air driven by the convection fan. The heated air is kept in the oven and

force-circulated and reheated by the convection heater.

CONVECTION COOKING SYSTEM

This oven is designed with a hot air heating system where food is not directly heated by the convection heater, but is heated by forced circulation of the hot air produced by the convection heater.

The air heated by the convection heater 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

convection heater, passes through the convection 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 convection heater is

de-energized. When the temperature inside the oven cavity drops below the selected temperature, the con- vection heater is energized again. In this way, the in- side of the oven cavity is maintained at approximately the selected temperature.

When the convection time reaches 0, the convection heater is deenergzed and the convection fan stops op- erating and the oven shutts off.

Upon completion of the cooking time, the audible sig- nal 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 tem- perature is above 118 OC., the circuit to RY5 will be maintained (by the thermistor circuit) to continue op- eration of the cooling fan motor until the temperature drops below 118 OC., at which time the relay will be de-energized, turning off the fan motor. Relay RY3 will however, open as soon as the convection cycle has ended, turning off the convection fan motor.This will now cool and allow the damper door to open.

DAMPER OPEN-CLOSE MECHANISM

Usually, the damper is in the open position except during convection cooking.

Damper position is set automatically by damper motor, damper switch, motor cam and damper shaft.

These components are operated by a signal that judges if microwave cooking or convection cooking operation is selected by the CPU unit.

Microwave Cooking:

Damper is in the open position, because a portion of cooling air is channeled through the cavity to remove steam and vapors given off from the heating foods.

It is then exhausted at the top of the oven cavity into a condensation compartment.

Convection Cooking:

Damper is in the closed position, so that no hot air will be allowed to leak out the oven cavity.

Damper Operation

I, When power supply cord is plugged in:

l-l. When power supply cord is plugged in, a sig- nal is sensed in the control unit, and operates shut-off relay (RY6).

1-2. Contacts of shut-off relay (RY6) close, the

damper motor is energized, opening the damper door.

1-3. When the damper is moved to the open posi- tion by the damper cam dampe switch is closed (ON position).

1-4. The signal of damper switch is re-sensed in the control unit and shut-off relay (RY6) is turned off.

1-5. The 240 volts A.C. to the damper motor is stopped and the motor turns off.

2.When oven is microwave cooking: Damper is in the open position.

3.When oven is convection cooking:

3-l. Damper motor is energized by touching the convection, temperature and START pads.

3-2. When damper is in the closed position (damper switch is OFF), its signal is sensed by the control unit, and shut-off relay (RY6) is de-energized.

3-3. The damper is held in the closed position during the convection cooking operation.

3-4. At the end of the convection cooking, shut-off relay (RY6) is energized, and the damper is returned to the open position.

NOTE: If the damper door is not in the proper position,

closed durin convection or open durning microwave, the control unit will stop oven op- eration after 1 minute.

Cooking		Mode		Operation of Damper
Microwave			cooking	OPEN
Convection			cooking	CLOSE
Sensor		cooking		OPEN
Automatic			mix cooking	CLOSE
Grill	cooking			CLOSE
Slow	cooking			CLOSE

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