Operation Sequence; Off Condition; Microwave Cooking Condition - Electrolux MC2660E (EU) Service Manual

Microwave ovens

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Table Of Contents

Table of Contents

OFF CONDITION

Closing the door activates the door interlock switch (monitored latch switch).

IMPORTANT

When the oven door is closed, the monitor switch contacts COM - NC must be open.

When the microwave oven is plugged in a wall outlet (230V (EU) / 230-240V (UK) 50Hz), the noise filter is

energized.

Figure 0-1 on page 32

NOTE: When the oven door is opened, the oven lamp comes on at this time.

MICROWAVE COOKING CONDITION

HIGH COOKING

Enter a desired cooking time by rotating the time/weight knob

and start the oven by touching START pad.

Figure 0-2 on page 32

1. The line voltage is supplied to the primary winding of the power transformer. The voltage is converted

to about 3.3 volts A.C. output on the filament winding and high voltage of approximately 2000 volts

A.C. on the secondary winding.

2. The filament winding voltage (3.3 volts) heats the magnetron filament and the high voltage (2000

sent to the voltage doubling circuit, where it is doubled to negative voltage of approximately

3. The 2450 MHz microwave energy produced in the magnetron generates a wave length of 12.24 cm.

This energy is channelled through the waveguide (transport channel) into the oven cavity, where the

food is placed to be cooked.

4. When the cooking time is up, a single tone is heard and the relays RY1 + RY3 + RY4 go back to their

home position. The circuits to the oven lamp, power transformer, fan motor and turntable motor are cut off.

5. When the door is opened during a cook cycle, the switches come to the following condition.

SWITCH

Monitor switch

Monitored latch switch

Stop switch

The circuits to the power transformer, fan motor and turntable motor are cut off when the monitored latch

switch is opened. The oven lamp remains on even if the oven door is opened after the cooking cycle has been

interrupted, because the relay RY1 stays closed. Shown in the display is the remaining time.

6. MONITOR SWITCH CIRCUIT

The monitor switch (SW2) is mechanically controlled by oven door, and monitors the operation of the

monitored latch switch (SW1)

6-1 When the oven door is opened during or after the cycle of a cooking program, the monitored latch

switch (SW1), and stop switch (SW3) must open their contacts (COM-NO) first. After that the

contacts (COM - NC) of the monitor switch (SW2) can be closed.

6-2 When the oven door is closed, the contacts (COM - NC) of the monitor switch (SW2) must be

opened first. After that the contacts of the monitored latch switch (SW1) and stop switch (SW3)

are closed.

6-3 When the oven door is opened and the contacts of the monitored latch switch (SW1) remain closed,

the fuse (F1) F8A will blow, because the monitor switch is closed and a short circuit is caused.

SOI 05.06 FV