Section 2 Operation; Operating Sequence Description; Off Condition; Cooking Condition - Electrolux ICON E30SO75ESS Technical & Service Manual

Operating Sequence Description

The following is a description of component functions
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 oven is plugged in, 240 volts A.C. is supplied to the
control unit. (See Figure 2-1).
1. The display will show "WELCOME TOUCH CLEAR
AND TOUCH CLOCK".
To set any program or set the clock, you must first
touch the STOP/CLEAR pad. The display will clear,
and " : " appears.
NOTE: When door is opened, the oven lamp comes on.
2. A signal is input to control unit, energizing the coil of
shut-off relay (RY-4). RY-4 contacts close, completing
a circuit to the damper motor. The damper motor now
operates moving the damper to the open position,
thereby closing the contacts of damper switch and
sending a signal to the control unit. The coil of relay
RY-4 is de-energized, opening its contacts, thereby
turning off the damper motor.

COOKING CONDITION

Program desired cooking time with Variable Cooking
Control by touching the NUMBER pads and the power
level pad. When the START button is touched, the
following operations occur:
1. The contacts of relays are closed and components
connected to the relays are turned on as follows.
(For details, refer to Figure 2-2)
RELAY CONNECTED COMPONENTS
RY-1 Oven Lamp / Turntable Motor
RY-2 Power Transformer
RY-3 Heating Element
RY-4 Damper Motor
RY-5 Convection Motor
RY-6 Fan Motor
2. 240 volts AC is supplied to the primary winding of
the power transformer and is converted to about
3.3 volts AC output on the filament winding, and
approximately 2300 volts AC on the high voltage
winding.
3. The filament winding voltage heats the magnetron
filament and the H.V. winding voltage is sent to a
voltage doubler circuit.
4. The microwave energy produced by the magnetron
is channeled through the waveguide into the cavity
feedbox, and then into the cavity where the food
is placed to be cooked.
5. Upon completion of the cooking time, the power
transformer, oven lamp, etc. are turned off, and the
generation of microwave energy is stopped. The
oven will revert to the OFF condition.
6. When the door is opened during a cook cycle,
monitor switch, door sensing switch, relay (RY1), the
primary interlock relay (RY2) and the secondary
interlock switch are activated with the following
results. The circuits to the turntable motor, the
cooling fan motor, and the high voltage components
are de-energized, the oven lamp remains on, and the
digital read-out displays the time still remaining in the
cook cycle when the door was opened.
7. The monitor switch is electrically monitoring the
operation of the primary interlock relay (RY2) and the
secondary interlock switch and is mechanically
associated with the door so that it will function in the
following sequence.
(1) When the door opens from a closed position, the
primary interlock relay (RY2) and the secondary
interlock switch open their contacts. And contacts
of the relay (RY1) remain closed. Then the
monitor switch contacts close.
(2) When the door is closed from the open position,
the monitor switch contacts first open, and then
the contacts of the secondary interlock switch
close. And contacts of the relay (RY1) open.
If the primary interlock relay (RY2) and the secondary
interlock switch fail with their contacts closed when the
door is opened, the closing of the monitor switch contacts
will form a short circuit through the monitor fuse, relay
(RY1), primary interlock relay (RY2) and the secondary
interlock switch, causing the monitor fuse to blow.
2-1
Operation