Sharp R-210A Service Manual page 11

PROCEDURE
LETTER
Initial temperature .................................................................................................. T1 = 11 C
Temperature after (60 + 2) = 62 sec. ..................................................................... T2 = 21 C
Temperature difference Cold-Warm ....................................................................
Measured output power
The equation is "P = 70 x T" ....................................................... P = 70 x 10 C = 700 Watts
JUDGMENT: The measured output power should be at least
CAUTION: 1 C CORRESPONDS TO 70 WATTS. REPEAT MEASUREMENT IF THE POWER IS
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 T (˚C) during this microwave
heating period, the calorie of the water is V x T.
The formula is as follows;
P x t / 4.2 = V x
Our condition for water load is as follows:
Room temperature .................. 23 2˚C
Water load. ...... 2000 ml
P = 60 x
Measuring method:
A) The two water containers must be prepared.
The water container must be one (1) litre beaker made of Pyrex glass and its diameter
approximately 12cm.
B) Put the one (1) litre water into each beaker (Each beaker has one litre water). The initial
temperature of the water should be 23 1˚C.
C) Mark T1 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 (2) beakers as touching each other in the centre of the oven cavity.
E) Set the timer to 2 minutes and 20 seconds, start the oven at 100% power.
F) The time must be measured with stopwatch or wristwatch.
G) After 2 minutes and 20 seconds, stop the oven by opening the door.
H) Put the two (2) beakers out of the oven cavity and measure the temperature of the water by stirring
the water with thermometer and note them.
Initial temperature............................................................................... T1 = 23˚C T2 = 24˚C
Temperature after 2 min. 22 sec. ...................................................... T1 = 33˚C T2 = 34˚C
Temperature difference Cold-Warm ............................................... T1 = 10˚C
Mean temperature rise T .......................... T = ( T1
Measured output power
The equation is P= 60 x T ......................................................... P= 60 x 10˚C = 600 Watts
NOTE: The measured output power should be at least 15 % of the rated output power.
TEST PROCEDURES
INSUFFICIENT.
1000g
1000g
T1˚C
T P (W) = 4.2 x V x T / t
Initial temperature ........ 23 1 C
T
COMPONENT TEST
Heat up for 62 sec.
Power supply Voltage .................. Rated voltage
Example
T2) / 2 = (10˚C+10˚C) / 2 = 10˚C
9
T1 = 10 C
15 % of the rated output power.
1000g
T2˚C
Heating time ..... 2 min. 20 sec.
T2 = 10˚C
R-210A