Specifications

Ver SG 9/200 45 Sharp Electronics Corporation
Damper Open-Close Mechanism
Below is a description of the Damper -Close Mechanism that is used in some convection
microwave ovens.
The Damper is usually open except during convection cooking. The Damper position is
set automatically by the damper motor, motor cam, and damper shaft. These components
are operated by a signal that is determined by whether microwave or convection cooking
has been selected at the control unit.
Microwave
The damper is in the open position because a portion of the cooling air is channeled
through the cavity to remove steam and vapors given off by heating foods. It is then
exhausted at the top of the oven cavity into a condensation compartment.
Convection Cooking
The damper is closed preventing hot air from escaping the oven cavity.
Damper Operation
1. When power is applied:
1.1 A signal is sensed in the control unit, operating the shut-off relay.
1.2 Contacts of the shut -off relay close, damper motor energizes, damper door
opens.
1.3 When damper door is moved to open position by damper cam, damper switch
is closed (ON Position).
1.4 The signal from the damper switch is re-sensed by the control unit, and the
shut-off relay is turned off.
1.5 The 120 volts to the motor is shut off.
2. When the oven is cooking in the microwave mode, the damper is in the open
position.
3. When the oven is in the convection mode:
3.1 The damper is energized by touching the convection, temperature, and start
pads.
3.2 When the damper is in the closed position (damper switch OFF), it’s signal is
sensed by the control unit and the shut off relay is de-energized.
3.3 The damper is held in the closed position during convection cooking.
3.4 At the end of the convection cook cycle, the shut relay is energized and the
damper returns to the open position.
NOTE: If the damper door is not in the proper position (Open for microwave cooking,
closed for convection cooking), the control unit stops oven operation after 1 minute.