Sharp R-961 (W) - Function of Important Components

FUNCTION OF IMPORTANT COMPONENTS
DOOR OPEN MECHANISM
The door can be opened by pushing the open button on the
control panel. When the open button is pushed, the open
lever pushes latch head on the door upward.
Door
Le
f Latch head
Open lever
Figure D-1. Door Open Mechanism
MONITORED LATCH SWITCH SW1, AND
DOOR SWITCH SW3
1. When the oven door is closed, the contacts COM-NO of
each switch must be closed.
2. When the oven door is opened, the contacts COM-NO of
each switch must be opened.
MONITOR SWITCH SW2
The monitor switch is activated (the contacts opened) by the
upper latch head on the door while the door is closed. The
switch is intended to render the oven inoperative by means
of blowing the fuse F2 (F8A) when the contacts of the latch
switch SW1 fail to open when the door is opened.
Function
1. When the door is opened, the contacts (COM-NC) of
monitor switch SW2 close (to the ON condition) due to
their being normally closed and contacts (COM-NO)
open. At this time the stop switch SWS is in the OFF
condition (contacts open) due to their being normally
open contact switches.
2. As the door goes to a closed position, the monitor switch
SW2 contacts (COM-NC) are opened and contacts
(COM-NO) closed and stop switch SW3 contacts
COM-NQO are closed and then the monitored latch switch
closes.(On opening the door, each of these switches
operate inversely.)
3. Ifthe door is opened and the monitored latch switch SW1
contacts fail to open, the fuse F2 (F8A) blows immediately
after closing of the monitor switch (COM-NC) contacts.
CAUTION: BEFORE REPLACING A BLOWN FUSE F2
F8A TEST THE MONITORED LATCH SWITCH,
AND MONITOR SWITCH FOR PROPER
OPERATION.
(REFER TO CHAPTER “TEST PROCEDURE’).
R-961 -
10
FUSE F1 15A 250V
lf the wire harness or electrical components are short-
circuited, this fuse F1 15A 250V blows to prevent an electric
shock or fire hazard.
FUSE F2 F8A 250V
1. If the wire harness or electrical components are short-
circuited, this fuse blows to prevent an electric shock or
fire hazard.
2. The fuse also blows when (st latch switch SW1 remains
closed with the oven door open and when the monitor
switch SW2 contact (COM-NC) closes.
FUSE F3 F10A 250V
1. If the wire harness or electrical components are short-
circuited, this fuse blows to prevent an electric shock or
fire hazard.
2. The fuse also blows when the asymmetric rectifier, H.V.
rectifier,.H.V. wire harness, H.V. capacitor, magnetron or
secondary winding of high voltage transformer is shorted.
T/C TRANSFORMER
T/C transformer converts A.C. line voltage into low voltage to
drive the control unit.
THERMAL
CUT-OUT
TC1
170°C
(GRILL)
The thermal cut out protects the oven against overheat
during grill cooking, convection cooking or dual (combina-
tion) cooking. If the temperature rises above 1 70°C because
the fan motor is interrupted, the air inlet ductis blocked or the
ventilation openings are obstructed, the thermal cut-out
opens and switches off all the electrical pars.
The defective thermal cut-out must be replaced with a new
one.
THERMAL CUT-OUT TC2 145°C (MG)
This thermal cut-out protects the magnetron against over-
heat. If the temperature goes up higher than1 45°C because
the fan motor is interrupted or the ventilation openings are
blocked, the thermal! cut-out TC2 will open and line voltage
to the high voltage transformer T will cut off and operation of
the magnetron MG will be stopped. The defective thermal
cut-out must be replaced with a new one.
THERMAL CUT-OUT TC3 190°C (CONV.)
The thermal cut out protects the convecion motor CM
against overheat. If the temperature of the thermal cut-out
TC3 rises above 190°C because the convection fan is
interrupted, the ventilation openings are obstructed or the
other abnormal matter occurs, the thermal cu-out opens and
switches off the convection heating element.When the oven
cools itself down to the operating temperature of 175°C, the
contacts of the thermal cut-out will close again.
THERMAL CUT-OUT TC4 95°C (FAN MOTOR)
This thermal cut-out protects the fan motor against overheat.
If its temperature goes up higher than 95°C be«ause the fan
motor is locked or the ventilation openings ae blocked, the
contacts
of
the
thermal
cut-out
will
open
ani
switch
off
the
oven.
When
the
thermal
cut-out
coolsitself
dawn
to
75°C,
the
contacts
of
the
thermal
cut-out
will
close
agin.