MICROWAVE MEASUREMENT
After adjustment of door latch switches, monitor switch and door are completed individually or collectively, the following leakage test must be performed with a survey instrument and it must be confirmed that the result meets the requirements of the performance standard for micro- wave oven.
REQUIREMENT
The safety switch must prevent microwave radiation emis- sion in excess of 5mW/cm2 at any point 5cm or more from external surface of the oven.
PREPARATION FOR TESTING:
Before beginning the actual test for leakage, proceed as follows;
1.Make sure that the test instrument is operating nor- mally as specified in its instruction booklet. Important:
Survey instruments that comply with the requirement for instrumentations as prescribed by the performance standard for microwave ovens must be used for test- ing.
Recommended instruments are:
NARDA 8100
NARDA 8200
HOLADAY HI 1500
SIMPSON 380M
2.Place the oven tray into the oven cavity.
3.Place the load of 275 ± 15ml of water initially at 20
± 5˚C in the centre of the oven tray. The water container should be a low form of 600 ml beaker with inside diameter of approx. 8.5cm and made of an electrically
The placing of this standard load in the oven is impor- tant not only to protect the oven, but also to insure that any leakage is measured accurately.
4.Close the door and turn the oven ON with the timer set for several minutes. If the water begins to boil before the survey is completed, replace it with 275ml of cool water.
5.Move the probe slowly (not faster that 2.5cm/sec.) along the gap.
6.The microwave radiation emission should be meas- ured at any point of 5cm or more from the external surface of the oven.
mW cm 2
mW cm 2
Microwave leakage measurement at 5 cm distance
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