Section 2 Operation
2-5
MONITOR SWITCH
The monitor switch is activated (the contacts opened)
by the latch head on the door while the door is closed.
The switch is intended to render the oven inoperative, by
means of blowing the monitor fuse, when the contacts of
the secondary interlock relay (RY2) and primary interlock
switch fail to open when the door is opened.
Functions:
1. When the door is opened, the monitor switch
contact close (to the ON condition) due to their
being normally closed. At this time the secondary
interlock relay (RY2), and primary interlock switch
are in the OFF condition (contacts open) due to their
being normally open contact switches. The contacts
of relay (RY1) are in the ON condition (contacts
close).
2. As the door goes to a closed position, the monitor
switch contacts are first opened and then the door
sensing switch and the primary interlock switch
contacts close. (On opening the door, each of these
switches operate inversely.)
3. If the door is opened, and the secondary interlock
relay (RY2) and primary interlock switch contacts fail
to open, the monitor fuse blows simultaneously with
closing of the monitor switch contacts.
THERMAL CUT-OUT (CAVITY)
This thermal cut-out is located on the top of the oven
cavity. It is designed to prevent damage to the oven unit
if the food in the oven catches
f
re due to overheating
produced by improper setting of cooking time or failure
of control unit. Under normal operation, the thermal
cut-out remains closed. However, the thermal cut-out
will open at 248°F (120°C) causing the oven to shut
down.
Before replacing a blown monitor fuse test the
door sensing switch, secondary interlock relay
(RY2), relay (RY1), primary interlock switch and
monitor switch for proper operation. (Refer to
“Test Procedure”).
CAUTION
Monitor fuse and switch are replaced as an assembly.
NOTE
THERMAL CUT-OUT (HOOD)
This thermal cut-out located on the right base plate. It
is designed to automatically turn on the hood fan motor
whenever the hot air rising from the conventional range
below causes the temperature at the thermal cut-out to
rise to 158°F (70°C) or higher, thus removing this hot air
from around microwave oven. When the temperature
around the thermal cut-out drops to 104°F (40°C) or
lower, the thermal cut-out shuts off the hood fan motor.
TURNTABLE MOTOR
The turntable motor rotates the turntable located on
the bottom of the oven cavity, so that the foods on the
turntable cook evenly during cooking. Turntable will turn
in either direction.
COOLING FAN MOTOR
The cooling 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 channelled through the oven
cavity to remove steam and vapors given off from the
heating foods. It is then exhausted through exhausting
air vents at the oven cavity.
HOOD FAN MOTOR
The hood fan motor is a four-speeds, single-phase,
double pole induction type, requiring a hood fan
capacitor. It is located outside the upper rear part of
the oven cavity. The hood fan motor removes hot air
from around the oven as it rises from the conventional
electric or gas range over which it is installed. This air is
then expelled either vertically or horizontally through the
customer supplied duct system, or discharged back into
the kitchen.
HOOD LAMP
The hood lamps are mounted at the hood lamp angle on
the base cover. The hood lamps can be turned off and
on.
