Sharp R-4H54 - Page 10

R-4H54
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
MICROWAVE OUTPUT POWER (2 LITRE WATER LOAD)
The following test procedure should be carried out with the microwave oven in a fully assembled
condition (with outer case fitted). Microwave output power from the magnetron can be measured
by way of substitution, i.e. it can be measured by using a 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. On the other hand, if the temperature of the water with V(ml) rises
AT (“C) during this microwave heating period, the calorie of the water is V x AT.
The formula is as follows;
P
8330 x AT
=
t
, Our condition for the water load is as follows:
/
Room temperature
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 23+2X
Power supply Voltage
I
. ..- . . . . . . . . . Rated voltage
Water load
. . . ...2000 ml
i
Initial temperature
. . . . . . . 23 +I “C
Heating time . . . . . . 1 min. 51
sec.
P = 75 x AT
1
I
Measuring method:
A) Use two 1 litre Pyrex beakers with a diameter of approximately of 12cms.
B) Place 1 litre of 23°C water in each beaker.
C) Mark Tl on the one beaker and mark T2 on the other one. And stir the water and measure the
temperature of water the thermometer and note them. The graduation of the thermometer must
be scaled by 0.1 “C at minimum and an accurate mercury thermometer is recommended.
D) Place the two beakers as touching each other in the centre of the cavity.
E) Set the timer to 1 minute and 51 seconds at 100% power (the time required to raise the water
temperature IO degrees C.)
F) The time must be measured with stopwatch or wristwatch.
G) After 1 minute and 51 seconds stop the oven by opening the door.
H) Remove the two beakers from the oven and measure the temperature of the water by stirring
the water with the thermometer and noting the readings.
Example
Initial temperature . . . . . . . . . . ..*....................*........................................*....
Tl = 23°C T2 = 24°C
Temperature after 1 min.
51
sec. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tl
= 33°C T2 = 34°C
Temperature difference
Cold-Warm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AT1 = 10°C AT2 =
10°C
Mean temperature rise AT
. . . . . . . .
AT = (AT1 +AT2) / 2 = (10°C + IO’C) / 2 = 10°C
Measured output power
The equation
is “P=
75 x
AT” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
P=
75 x 10°C =
/
750 Watts
NOTE: The measured output power should be at least +I5 % of the rated output
power.
CAUTION: 1 “C CORRESPONDS TO 75 WATTS.
REPEAT MEASUREMENT IF THE POWER IS INSUFFICIENT.
m OC)
IT2 OCt
Tr2 OC)
Heat up for 1 min. 51 sec.
MICROWAVE OUTPUT POWER (1 LITRE WATER LOAD)
(RD82A02J)
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 705, 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 cal-
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