SOI 12.06 FV
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TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
A
MAGNETRON TEST
NEVER TOUCH ANY PART IN THE CIRCUIT WITH YOUR HAND OR AN INSULATED
TOOL WHILE THE OVEN IS IN OPERATION.
CARRY OUT 3D CHECK
Isolate the magnetron from high voltage circuit by removing all leads connected to the
filament terminal.
To test for an open circuit filament use an ohmmeter to make a continuity test between
the magnetron filament terminals, the meter should show a reading of less than 1 ohm.
To test for a short circuit filament to anode condition, connect ohmmeter between one of
the filament terminals and the case of the magnetron (ground). This test should be
indicated an infinite resistance. If a low or zero resistance reading is obtained then the
magnetron should be replaced.
MICROWAVE OUTPUT POWER (IEC-60705-1988)
The following test procedure should be carried out with the microwave oven in a fully
assembled condition (outer case fitted). Microwave output power from the magnetron
can be measured by way of IEC 60705, i.e. it is measured by how much power the
water load can absorb. To measure the microwave output power in the microwave oven,
the relation of calorie and watt is used. When P(W) heating works for t(second),
approximately P x t/4.187 calorie is generated. On the other hand, if the temperature of
the water with V(ml) rises
Δ
T
(°C) during this microwave heating period, the calorie of
the water is V x
Δ
T.
The formula is as follows;
P x t / 4.187 = V x
Δ
T+0.55 x mc (T2-T0)
Our condition for water load is as follows:
Room temperature.....................around 20°C
Water load..........................................1000 g
Heating time........................................47 sec.
T2......................................Final Temperature
P (W) = 4.187 x V x
Δ
T / t
Power supply Voltage........Rated voltage
Initial temperature(T1).............10 ± 1°C
Mass of container (mc)....................330 g
P = 90 x
Δ
T + 0.55 x mc (T2-T0)/47
Measuring condition:
1. Container
The water container must be a cylindrical borosilicate glass vessel having a maximum
material thickness of 3 mm and an outside diameter of approximately 190 mm.
2. Temperature of the oven and vessel.
The oven and the empty vessel are at ambient temperature prior to the start of the
test.
3. Temperature of the water
The initial temperature of the water is (10 ± 2)°C.
4. Select the initial and final water temperature so that the maximum difference
between the final water temperature and the ambient temperature is 5K.
5. Select stirring devices and measuring instruments in order to minimize addition or
removal of heat.
6. The graduation of the thermometer must be scaled by 0.1°C at minimum and an
accurate
thermometer.
7. The water load must be (1000 ± 5) g.
8. “t” is measured while the microwave generator is operating at full power. Magnetron
filament heat-up time is not included.
NOTE: The operation time of the microwave ovens is “t + 3” sec. (3 sec. is magnetron
filament
heat-up
time.)
