Sharp R-520LK Manual Do Utilizador

11

The door is opened by pushing the open button on the con-
trol 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 released from latch hook.
Now the door will open.

The primary interlock switch is mounted in the lower position
of the latch hook and the door sensing switch in the second-
ary 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  secondary  interlock  system
consists of the door sensing switch and secondary interlock
relay located on the control circuit board.

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 second-
ary interlock relay (RY) 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 (RY)
and primary interlock switch are in the OFF condition
(contacts open) due to their being normally open contact
switches.

.  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

(RY) and primary 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,
SECONDARY INTERLOCK RELAY (RY), RE-
LAY  (RY1),  PRIMARY  INTERLOCK  SWITCH
AND  MONITOR  SWITCH  FOR  PROPER
OPERATION.  (REFER TO  CHAPTER  "TEST
PROCEDURE").

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. The turntable may turn in either
direction.

The cooling fan motor drives a blade which draws external
cool air. This cool air is directed through the air vanes sur-
rounding the magnetron and cools the magnetron. This air
is channeled through the oven cavity to remove steam and
vapors given off from the heating foods. It is then exhausted
through the exhausting air vents at the oven cavity.

The cavity temperature fuse located on the top of the oven
cavity, is designed to prevent damage to the oven by fire.
If the food load is overcooked, by either error in cook time
or  defect  in  the  control  unit,  the  cavity  temperature  fuse
will open.
Under normal operation, the cavity temperature fuse remains
closed. However, when abnormally high temperatures are
reached within the oven cavity, the cavity temperature fuse
will open at 30

O

F(150

O

C) causing the oven to shut down.

NOTE: This is a fuse. It does not reset.

1.  The monitor fuse blows when the contacts (COM-NO) of

the primary interlock relay (RY) and secondary interlock
switch remain closed with the oven door open and when
the monitor switch closes.

.  If the wire harness or electrical components are short-

circuited, this monitor fuse blows to prevent an electric
shock or fire hazard.

The magnetron temperature fuse located near the magne-
tron is designed to prevent damage to the magnetron if an
over heated condition develops in the tube due to cooling
fan failure, obstructed air guide, dirty or blocked air intake,
etc.
Under normal operation, the magnetron temperature fuse

Door S ensing
S witch

Monitor S witch

S witch Lever

P rimary Interlock
S witch

Latch Heads

Door