Sharp R-961 (W) - Page 13

FUNCTION OF IMPORTANT COMPONENTS
ASYMMETRIC RECTIFIER
The asymmetric rectifier is solid state device that prevents
current flow is both directions. And it prevents the tempera-
ture rise of the high voltage transformer by blowing the fuse
E3 F10A when the high voltage rectifier is shorted.
ASYMMETRIC
RECTIFIER
C/ HIGH VOLTAGE RECTIFIER
The rated peak reverse voltage of D1 of the asymmetric
rectifier is 6 KV The rated peak reverse voltage of D2 of the
asymmetric rectifier is 1.7 KV. D1 and D2 of the asymmetric
rectifier or high voltage rectifier are shorted when the each
peak reverse voltage goes beyond the each rated peak
reverse voltage. (The process of the blowing the fuse F3
F10A.)
1. The high voltage rectifier is shorted by some fault when
microwave cooking or dual cooking.
2. The peak reverse voltage of D2 of the rectifier goes
beyond the rated peak reverse voltage 1.7 KV in the
voltage doubler circuit.
3. D2 of the rectifier is shorted.
4. The large electric currents flow through the high voltage
winding of the high voltage transformer.
5. The large electric currents beyond 10A flow through the
primary winding of the high voltage transformer.
The fuse F3 F10A blows by the large electric currents.
The power supplying to the high voltage transformer is
cut off.
N@
NOISE FILTER
The noise filter assembly prevents radio frequency interfer-
ence that might flow back in the power circuit.
TURNTABLE MOTOR ITM
The turntable motor drives the roller stay to rotate the
turntable.
FAN MOTOR EM
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 channeled
through the oven cavity to remove steam and vapours given
off from the heating foods. It is then exhausted through the
exhausting air vents at the oven cavity.
CONVECTION MOTOR CM
The convection motor drives the convection fan and provide
the heated air.
GRILL HEATING ELEMENT GH
The grill heating element is provided to brown the food and
is located on the top of the oven cavity.
R-961 -
11
CONVECTION HEATING ELEMENT CH
The convection heating element is located at the rear 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 heating element.
CONVECTION COOKING SYSTEM
This oven is designed with a hot air heating system where
food is not directly heated up by the convection heating
element, but is instead heated by forced circulation of the hot
air produced by the convection heating element.
The air heated by the convection heating element is circu-
lated 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
back 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 rear wall.
Without leaving the oven, this hot air is reheated by the
convection heating element, passes through the convection
passage and enters the inside of the oven cavity again, ina
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 heating element is de-
energized. When the temperature inside the oven cavity
drops below the selected temperature, the convection heat-
ing element is energized again. In this way, the inside of the
oven cavity is maintained at approximately the selected
temperature.
When the convection time reaches “0”, the convection heat-
ing element is de-energized and the convection fan stops
operating and the oven shuts off. At the high temperature
(more than 104°C), the fan motor remains rotating. Automati-
cally the fan motor will be shut down at low temperature (less
than 104°C).
Grill Heating
Door Elements
Oven Cavity
Convection
Passage
Convection
Heating
Element
Auxiliary
Fan
Convection
Motor
Convection
Fan
Turntable
Motor Roller Stay
Figure D-2. Convection Cooking System