Microwave Measurement Procedure - Sharp R-1880LS Service Manual

R-1880LS/LST
MICROWAVE MEASUREMENT PROCEDURE (USA)
A. Requirements:
1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven should
not exceed 1mW/cm  at any point 5cm or more from the external surface of the oven, measured prior to acquisition by a purchaser,
and thereafter (through the useful life of the oven), 5 mW/cm
) Safety interlock switches Primary interlock relay and door sensing switch shall prevent microwave radiation emission in excess of
the requirement as above mentioned, secondary interlock switch shall prevent microwave radiation emission in excess of 5 mW/cm
at any point 5cm or more from the external surface of the oven.
B. Preparation for testing:
Before beginning the actual measurement of leakage, proceed as follows:
1) Make sure that the actual instrument is operating normally as specified in its instruction booklet.
Important:
Survey instruments that comply with the requirement for instrumentation as prescribed by the performance standard for micro-
wave ovens, 1 CFR 1030.10(c)(3)(i), must be used for testing.
) Place the oven tray in the oven cavity.
3) Place the load of 75±15 ml (9.8 oz) of tap water initially at 0±5½C (68½F) in the center of the oven cavity.
The water container shall be a low form of 600 ml (0 oz) beaker with an inside diameter of approx. 8.5 cm (3-1/ in.) and
made of an electrically nonconductive material such as glass or plastic.
The placing of this standard load in the oven is important not only to protect the oven, but also to insure that any leakage is
measured accurately.
4) Set the cooking control on Full Power Cooking Mode
5) Close the door and select a cook cycle of several minutes. If the water begins to boil before the survey is completed, replace it
with 75 ml of cool water.
C. Leakage test:
Closed-door leakage test (microwave measurement)
1) Grasp the probe of the survey instrument and hold it perpendicular to the gap between the door and the body of the oven.
) Move the probe slowly, not faster than 1 in./sec. (.5 cm/sec.) along the gap, watching for the maximum indication on the meter.
3) Check for leakage at the door screen, sheet metal seams and other accessible positions where the continuity of the metal has been
breached (eg., around the switches, indicator, and vents).
While testing for leakage around the door pull the door away from the front of the oven as far as is permitted by the closed latch
assembly.
4) Measure carefully at the point of highest leakage and make sure that the highest leakage is no greater than 4mW/cm
secondary interlock switch does turn the oven OFF before any door movement.
NOTE: After servicing, record data on service invoice and microwave leakage report.
at any point 5cm or more from the external surface of the oven.

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