PROCEDURE
LETTER
B
C
TEST PROCEDURES (CONT’D)
COMPONENT TEST
Calculation of output power;
-
Microwave output power . . . . .P (W) = 70 x AT (“C)
AT =
(ATL + ATR)
: average temperature rise
2
ATL = (Q2 - TLJ
ATR = (TRY -TRY 1
TL2
: water temperature after heating in left beaker
TLI :
water temperature before heating in left beaker
TR2 : water temperature after heating in right beaker
TRl
: water temperature before heating in right beaker
Measuring condition;
As the microwave output is affected by several conditions, the measurement should be made care-
fully with following attentions.
1. Initial temperature of salt water should be 20 f l°C. (The salt water should be contained bon (1)
percent of salt.) Well and quickly stir the water and the temperature measurement should be
done immediately after heating.
2. The graduation of thermometer should be scaled by 0.1 “C at minimum and an accurate mercury
thermometer is recommended.
3. Water container should be one (1) litre beaker made of Pyrex glass and its diameter approxi-
mately 12 cm.
4. Room temperature should be around 20°C.
5. Power supply voltage should be 220/240 volts.
POWER TRANSFORMER TEST
DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY
OVEN COMPONENTS OR WIRING.
Disconnect the primary input terminals and measure the resistance of the transformer with an ohm-
meter. Check for the continuity of the coils with the ohmmeter. On the RX1 scale, the resistance of
the primary coil should be less than 1.1 ohm (22OV)/1.2 ohm (24OV) and the resistance of high
voltage coil should be approximately 105 ohms: and the resistance of filament coil should be less
than 1 ohms. With 220/240 volts AC applied to the primary winding, the voltage across the filament
winding should be approximately 3.15 volts A.C. (HIGH VOLTAGES ARE PRESENT TO HIGH
VOLTAGE TERMINAL, SO EXTREME CAUTION SHOULD BE OBSERVED.)
RECTIFIER TEST
DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY
OVEN COMPONENTS OR WIRING.
Isolate the rectifier from the circuit. Using the highest ohm scale of the meter, read the resistance
across the terminals and observe, reverse the leads to the rectifier terminals and observe meter
reading. If a short is indicated in both directions, or if an infinite resistance is read in both direc-
tions, the rectifier is probably defective and should be replaced.
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