8
Microwave service manual – Model:
microMD UK
Measurement of microwave power output
• 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.
• The water is contained in a cylindrical borosilicate
glass vessel having a maximum material
thickness of 3mm and an outside diameter of
approximately 190mm.
• The oven and the empty vessel are at ambient
temperature prior to the start of the test.
• The initial temperature (T1) of the water is
(10±2)°C. 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 centre of the turntable which is in
the lowest position and the microwave power
switched on.
• The time T for the temperature of the water
to rise by a value Δ T of (10±2)°K is measured,
where T is the time in seconds and ΔT 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.
• The microwave power output P in watts is
calculated from the following formula:
(I think there is some copy missing here!)
is measured while the microwave generator is
operating at full power. Magnetron filament
heat-up time is not included (about 3 sec).
• The water is stirred to equalize temperature
throughout the vessel, prior to measuring the
final water temperature.
• Stirring devices and measuring instruments
are selected in order to minimize addition or
removal of heat.
Notes: For simple tests of microwave power
output, conduct it by heating one litre of water for
one minute, minimum temperature rise should be
6°C
P =
4187 x (ΔT) + 0.55 X (T
2
- T
0
) X M
T
• T
2
: Temperature after heating
• T
0
: Temperature of bowl
• M: Weight of bowl
WATER LOAD
TURNTABLE
Disassembly and adjustment
1. Outer case removal
1) Disconnect the power supply cord from the
outlet.
2) Remove the screws from the rear and along side
edges of the case.
The outer case must be moved backward to be
lifted off.
