8.PROCEDURE FOR MEASURING MICROWAVE ENERGY LEAKAGE
A. CAUTIONS | B. MEASURING MICROWAVE ENERGY LEAKAGE | ||||||
(1) | Be sure to check a microwave emission prior to servicing | (1) | Pour 275±15cc of 20±5°C water in a beaker which is | ||||
(2) | the oven if the oven is operative prior to servicing. |
| graduated to 600 cc, and place the beaker in the center | ||||
The service personnel should inform the manufacturer, | (2) | of the oven. | |||||
| importer, or assembler of any certified oven unit found to | Set the energy leakage monitor to 2,450 MHz and use it | |||||
| have a microwave emission level in excess of |
| following the manufacturer’s recommended test | ||||
| 5mW/cm.sq. and should repair any unit found to have | (3) | procedure to assure correct result. | ||||
| excessive emission levels at no cost to the owner and | When measuring the leakage, always use the 2 inch | |||||
| should ascertain the cause of the excessive leakage. | (4) | (5cm) spacer supplied with the probe. | ||||
| The service personnel should instruct the owner not to | Operate the oven at its maximum output. | |||||
| use the unit until the oven has been brought into | (5) | Measure the microwave radiation using and | ||||
(3) | compliance. |
| electromagnetic radiation monitor by holding the probe | ||||
If the oven operates with the door open, the service |
| perpendicular to the surface being measured. (See | |||||
| personnel should; |
| Figure 7) | ||||
| - Tell the user not to operate the oven |
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| Move probe along shaded area. | ||||||
| - Contact the manufacturer and CDRH (Center for | ||||||
| Devices and Radiological Health) immediately. |
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| NOTE: Address on CDRH |
| Probe scanning speed | ||||
| Office of Compliance |
| less than 2.5 cm/sec. | ||||
| Center for Devices and Radiological Health |
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| 1390 Piccard Drive |
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| Rockville, Maryland 20850 |
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(4)The service personnel should check all surface and vent openings for microwave emission testing.
(5) Check for microwave energy leakage after every |
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servicing. The power density of the microwave radiation |
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leakage emitted by the microwave oven should not |
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exceed 1mW/cm.sq. And always start measuring of an |
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unknown field to assure safety for operating personnel |
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| Figure 7 | |
from radiation leakage. |
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NOTE: The standard is 5mW/cm.sq. while in the |
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customer’s home. 1mW/cm.sq. stated here is | C. MEASUREMENT WITH THE OUTER CASE REMOVED | |||||||||
manufacturer’s own voluntary standard for units in | ||||||||||
customer’s home. | (1) When you replace the magnetron, measure for | |||||||||
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| microwave energy leakage before the outer case is | ||||||||
EQUIPMENT | installed and after all necessary components are | |||||||||
• Electromagnetic energy leakage monitor (NARDA 8100B, | replaced or adjusted. Special care should be taken in | |||||||||
HOLADAY HI 1501) | measuring the following parts. | |||||||||
• 600cc glass beaker | - Around the magnetron | |||||||||
• Glass thermometer 100°C | - The waveguide | |||||||||
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| WARNING: AVOID CONTACTING ANY HIGH VOLTAGE | ||||||||
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| PARTS. | |||||||
Figure 6