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Theory of Operation
MW24-1100 MICROWAVE OVEN
3-7
#814888 - Revision A - May, 2009
DETAILED OPERATING SEQUENCE
The Simple Theory of Operation on the previous pages explains the basics of how a Wolf microwave oven works.
This Detailed Operating Sequence explains the component functions in greater detail during oven operation.
Off Condition
Closing the door activates the door sensing switch and secondary interlock switch. (In this condition, the monitor
switch contacts are opened.) When the oven is plugged in, 115 volts AC are supplied to the control unit
1.
The display will show flashing"WELCOME, PRESS CLEAR"
NOTE:
To set any program or set the clock, the STOP/CLEAR pad must be touched first. The display will clear,
and "
:
" will appear.
SCHEMATIC
NOTE:
CONDITION OF OVEN
1. DOOR CLOSED
2. CLOCK APPEARS ON DISPLAY
120V AC
60 Hz
OVEN
LAMP
TURN-
TABLE
MOTOR
FAN
MOTOR
MONITOR
SWITCH
H.V. RECTIFIER
MAGNETRON
SECONDARY
INTERLOCK
SWITCH
TTM
OL
FM
MONITOR
FUSE 20A
CAVITY
TEMP.
FUSE
MAGNETRON
TEMP.
FUSE
A1
A2
COM.
COM.
COM.
N.O.
N.C.
N.O.
DOOR
SENSING
SWITCH
(RY-1)
(RY-2)
CONTROL UNIT
PRIMARY
INTERLOCK
RELAY
B1
B2
GRN
POWER
TRANSFORMER
CAPACITOR 1.0µF
AC 2300V
AH SENSOR
Indicates components with potential above 250 Volts.
NOTE:
F1
F2
F3
Figure 3-10. Oven Schematic, Off Condition
Cooking Condition
Program desired cooking time by touching the NUMBER pads. Program the power level by touching the POWER
LEVEL pad and then a Number pad. When the START pad is touched, the following operations occur:
1.
The contacts of relays are closed and components are turned on as follows (
RELAY
CONNECTED COMPONENTS
RY-1
Oven Lamp / Turntable Motor / Fan Motor
RY-2
Power Transformer
2.
115 volts AC is supplied to the primary winding of the power transformer and is converted to approximately 3.3
volts AC output on the filament winding, and approximately 2300 volts AC on the high voltage winding.