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| TEST PROCEDURES |
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PROCEDURE | COMPONENT TEST |
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LETTER |
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| Initial temperature | T1 | = 11°C |
| Temperature after (60 + 2) = 62 sec | T2 | = 21°C |
| Temperature difference | ΔT1 | = 10°C |
| Measured output power |
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| The equation is “P = 70 x ΔT” | P = 70 x 10°C = 700 Watts | |
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JUDGMENT: The measured output power should be at least ± 15 % of the rated output power.
CAUTION: 1°C CORRESPONDS TO 70 WATTS. REPEAT MEASUREMENT IF THE POWER IS INSUFFICIENT.
1000g
1000g
T1˚C
Heat up for 62 sec.
1000g
T2˚C
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 ΔT (˚C) during this microwave heating period, the calorie of the water is V x ΔT.
The formula is as follows; |
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P x t / 4.2 = V x Δ T | P (W) = 4.2 x V x ΔT / t |
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Our condition for water load is as follows: |
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Room temperature | 23±2˚C | Power supply Voltage | Rated voltage | ||
Water load | 2000 ml | Initial temperature | 23±1°C Heating time | 2 min. 20 sec. | |
P = 60 x Δ T |
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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.
Example
Initial temperature | T1 = 23˚C | T2 | = 24˚C |
Temperature after 2 min. 22 sec | T1 = 33˚C | T2 | = 34˚C |
Temperature difference | ΔT1 = 10˚C ΔT2 | = 10˚C | |
Mean temperature rise ΔT | ΔT = (ΔT1 ± ΔT2) / 2 = (10˚C+10˚C) / 2 | = 10˚C | |
Measured output power |
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The equation is P= 60 x ΔT | P= 60 x 10˚C = 600 Watts | ||
NOTE: The measured output power should be at least ± 15 % of the rated output power.
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