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R-55TS-F
DOOR OPEN MECHANISM
The door is opened by pushing the open button on the
control panel, refer to the Figure D-1.
When the open button is pushed, the open button pushes up
the switch lever, and then the switch lever pushes up the
latch head. The latch heads are moved upward and re-
leased from latch hook. Now the door will open.
Door
Latch
Heads
Switch Lever
Figure D-1. Door Open Mechanism
DOOR SENSING AND SECONDARY INTERLOCK
SWITCHES
The secondary interlock switch is mounted in the lower
position of the latch hook and the door sensing switch in the
primary interlock system is mounted in the upper position of
the latch hook. They are activated by the latch heads on the
door. When the door is opened, the switches interrupt the
power to all high voltage components. A cook cycle cannot
take place until the door is firmly closed thereby activating
both interlock switches. The primary interlock system con-
sists of the door sensing switch and primary interlock relay
located on the control circuit board.
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 primary
interlock relay (RY2), relay (RY1) and secondary interlock
switch fail to open when the door is opened.
Functions:
1. When the door is opened, the monitor switch contacts
close (to the ON condition) due to their being normally
closed. At this time the primary interlock relay (RY2) and
secondary interlock switch are in the OFF condition
(contacts open) due to its being normally open contact
switches. But the contacts of relay (RY1) are closed to
turn on the oven lamp.
2. As the door goes to a closed position, the monitor switch
contacts are first opened and then the door sensing switch
and secondary interlock switch contacts close. At this time,
the contacts of the relay (RY1) and the primary interlock
relay (RY2) are in the OFF condition (contacts open)
DESCRIPTION AND FUNCTION OF COMPONENTS
Latch Hook
Door Sensing
Switch
Monitor Switch
Secondary
Interlock Switch
3. If the door is opened, and the primary interlock relay
(RY2) and the secondary interlock switch contact fail to
open, the monitor fuse blows simultaneously with closing
of the monitor switch contacts.
CAUTION: BEFORE REPLACING A BLOWN MONITOR
FUSE, TEST THE DOOR SENSING SWITCH,
RELAY (RY1), PRIMARY INTERLOCK RELAY
(RY2), SECONDARY INTERLOCK SWITCH
AND MONITOR SWITCH FOR PROPER OP-
ERATION. (REFER TO CHAPTER "TEST PRO-
CEDURE").
NOTE: MONITOR FUSE AND MONITOR SWITCH ARE
REPLACED AS AN ASSEMBLY.
TURNTABLE MOTOR
The turntable motor rotates the turntable located on the
bottom of the oven cavity, so that the food on the turntable
is cooked evenly. The turntable may 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 vents surround-
ing the magnetron and cools the magnetron. This air is
channelled 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.
THERMAL CUT-OUT 125˚C
This thermal cut-out protects the upper heater against
overheating. If the temperature goes up higher than 257˚F
(125˚C) because the fan motor is interrupted or the ventilation
openings are blocked, the thermal cut-out will open and
line voltages to all electrical parts will be cut off and the
operation of the oven will be stopped. The thermal cut-out
will not resume.
OVEN THERMOSTAT
The oven thermostat is located on the top of the oven cavity.
The oven thermostat will open at higher than 302˚F (150˚C).
And the oven thermostat will close at lower than 266˚F
(130˚C).
TEMPERATURE FUSE (MAGNETRON)
The temperature fuse, located near the magnetron, is
designed to prevent damage to the magnetron. If an over
heated condition develops in the magnetron due to cooling
fan failure, obstructed air guide, dirty or blocked air intake,
etc., the temperature fuse will open.
Under normal operation, the temperature fuse remains
closed. However, when abnormally high temperatures are
reached within the oven cavity, the temperature fuse will
open at 302˚F (150˚C), causing the oven to shut down.
UPPER HEATER
The upper heater is located on the top of the oven cavity
assembly. The upper heater sends out heat to cook foods.
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