Power Output Measurement - LG LMV1813SW Service Manual

8. POWER OUTPUT MEASUREMENT

(1) Microwave power output measurement is made
with the microwave oven supplied at its rated
voltage and operated at its maximum microwave
power setting with a load of (1000 ± 5) g of
potable water.
(2) The water is contained in a cylindrical
borosilicate glass vessel having a maximum
material thickness of 1/8" (3 mm) and an outside
diameter of approximately 7.6" (190 mm).
(3) The oven and the empty vessel are at ambient
Temperature (T0) prior to the start of the test.
(4) The initial temperature (T1) of the water is
(10 ± 1) °C (50°F) It is measured immediately
before the water is added to the vessel. After
addition of the water to the vessel, the load is
immediately placed on the center of the turntable
which is in the lowest position and the
microwave power switched on.
(5) The time t for the temperature of the water to
rise by a value T of (10 ± 1) °K is measured,
where t is the time in seconds and T is the
temperature rise. The initial and final water
temperatures are selected so that the maximum
difference between the final water temperature
and the ambient temperature is 5°K.
(6) The microwave power output P in watts is
calculated from the following formula :
4.187 Mw(T2 –T1)+0.55Mc(T2 –T0)
P =
is measured while the microwave generator is
operating at full power. Magnetron filament heat-up
time is not included. (about 3 seconds)
(7) The water is stirred to equalize temperature
throughout the vessel, prior to measuring the
final water temperature.
(8) Stirring devices and measuring instruments are
selected in order to minimize addition or removal
of heat.
Where
P is the microwave power output, in watts
Mw is the mass of the water, in grams
Mc is the mass of the container, in grams
T0 is the ambient temperature, in °C
T1 is the initial temperature of the water, in °C
T2 is the final temperature of the water, in °C
t is the heating time in seconds, excluding the magnetron filament heat-up time.
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t