R-20A1(S)VN
8 – 1
R218L(W)
CHAPTER 8.
TEST PROCEDURES
[1] Procedure A: MAGNETRON (MG) TEST
NEVER TOUCH ANY PART IN THE CIRCUIT WITH YOUR HAND OR AN INSULATED TOOL WHILE THE OVEN IS IN OPERATION.
CARRY OUT 3D CHECKS.
r should show a
reading of less than 1 ohm.
he magnetron
on should be replaced.
MICROWAVE OUTPUT POWER (1 litre water load)
icrowave output power
from the magnetron can be measured by IEC test procedure, i.e. it can be measured by using water load how much it can be absorbed by the water
load. 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(sec-
ond), approximately P x t/4.187 calorie is generated. On the other hand, if the temperature of the water with V(ml) rises T ( C) during this microwave
heating period, the calorie of the water is v x T.
Measuring condition:
1) Container
The water container must be a cylindrical borosilicate glass vessel hav ing 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 1) C
t temperature is
5 C.
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.
NOTE
Measuring method:
1) 1.Measure the initial temperature of the water before the water is added to the vessel.
(Example: The initial temperature T1 = 11 C)
2) Add the 1 litre water to the vessel.
3) Place the load on the centre of the shelf.
4) Operate the microwave oven at 100% for the temperature of the water rises by a value T of 10 C.
5) Stir the water to equalize temperature throughout the vessel.
C)
7) Calculate the microwave power output P in watts from above formula.
JUDGEMENT: The measured output power should be at least 15 % of the rated output power.
CAUTION: 1 C CORRESPONDS TO 80 WATTS. REPEAT MEASUREMENT IF THE POWER IS INSUFFICIENT.
The formula is as follows;
P x t / 4.187 = V x T+ 0.55 x mc (T2-T0)/4.187 P (W) = 4.187 x V x T / t + 0.55 x mc (T2-T0)/t
Our condition for water load is as follows:
Room temperature (T0) ......................... around 20°C Power supply ........................... VoltageRated voltage
Water load ...............................................................1000 g Initial temperature (T1) .................................... 10±1°C
Heating time .......................................................... 52 sec. Mass of container (mc) ...................................... 330 g
T2 ........................................................ Final Temperature T = T2 - T1 P = 80 x T + 0.55 x mc (T2-T0)/52
Room temperature ................................................................... To = 21 C
Initial temperature ..................................................................... T1 = 11 C
Temperature after (52 + 3) = 55 sec ...................................... T2 = 21 C
C
Measured output power
The equation is "P = 80 x T" .................... P = 80 x 10 C = 800 Watts
