R21LCF
6 – 3
3) If the door is opened, and the primary interlock relay (RY1) and
secondary interlock switch contacts 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, PRIMARY INTERLOCK
RELAY (RY1), SECONDARY INTERLOCK SWITCH AND
MONITOR SWITCH FOR PROPER OPERATION. (REFER
TO CHAPTER "TEST PROC
NOTE:
MONITOR FUSE AND MONITOR SWITCH ARE REPLACED
AS AN ASSEMBLY.
4. ANTENNA MOTOR
The antenna motor rotates the stirrer antenna located on the bottom of
the oven cavity, so that the food on the ceramic shelf is cooked evenly
during cooking. The antenna motor may turn in either direction.
5. 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 magne-
tron and cools the magnetron. This air is channelled through the oven
cavity to remove steam and vapors given off from the heating food. It
is then exhausted through the exhausting air vents at the oven cavity.
6. MONITOR FUSE
1) The monitor fuse blows when the contacts (COM-NO) of the pri-
mary interlock relay (RY1) and secondary interlock switch remain
closed with the oven door open and when the monitor switch
closes.
2) If the wire harness or electrical components are shortcircuited, this
monitor fuse blows to prevent an electric shock or fire hazard.
7. THERMAL CUT-OUT 145
°
C (MAGNETRON)
This thermal cut-out protects the magnetron against overheating. If the
temperature goes up higher than 293
°
F (145
°
C) because the fan
motor is interrupted or the ventilation openings are blocked, the ther-
mal cut-out will open and line voltages to the high voltage transformer
will be cut off and the operation of the magnetron will be stopped. The
thermal cutout will not resume.
8. THERMAL CUT-OUT 125
°
C (OVEN)
The thermal cut-out located on the top of the oven cavity is designed
to prevent damage to the oven if the food in the oven catches fire due
to over heating produced by improper setting of the cooking time or
failure of control unit. Under normal operation, the oven thermal cut-
out remains closed. However, when abnormally high temperatures are
reached within the oven cavity, the oven thermal cut-out will open at
257
°
F(125
°
C) causing the oven to shut down. The thermal cut-out will
not resume.
9. NOISE FILER
The noise filter prevents the radio frequency interference that might
flow back in the power circuit.
