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NASA-LLIS-0449
Lessons Learned - Migration of Conductive Contaminates in an Electrical Switch in Zero "G"
Year: 1990
Abstract: Description of Driving Event:
APU 2 Fuel Pump Heater was cycling high during flight. Detailed analysis of the thermal switch showed extreme wear from the switch bi-metal disc and case. Large amounts of conductive contaminates were found. Analysis showed that they came from the disc and case. It is concluded that excessive vibration caused the wear and in zero gravity particles were free to migrate into the electrical contacts, resulting in a higher disc deflection to open the thermostat contacts. The result is a higher heater turn off temperature.
APU 2 Fuel Pump Heater was cycling high during flight. Detailed analysis of the thermal switch showed extreme wear from the switch bi-metal disc and case. Large amounts of conductive contaminates were found. Analysis showed that they came from the disc and case. It is concluded that excessive vibration caused the wear and in zero gravity particles were free to migrate into the electrical contacts, resulting in a higher disc deflection to open the thermostat contacts. The result is a higher heater turn off temperature.
Subject: Hardware
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| contributor author | NASA - National Aeronautics and Space Administration (NASA) | |
| date accessioned | 2017-09-04T18:48:12Z | |
| date available | 2017-09-04T18:48:12Z | |
| date copyright | 33222 | |
| date issued | 1990 | |
| identifier other | KOBEQCAAAAAAAAAA.pdf | |
| identifier uri | http://yse.yabesh.ir/std;jsessionid=3826AF679D40527318548F1EFDEC014A/handle/yse/229407 | |
| description abstract | Description of Driving Event: APU 2 Fuel Pump Heater was cycling high during flight. Detailed analysis of the thermal switch showed extreme wear from the switch bi-metal disc and case. Large amounts of conductive contaminates were found. Analysis showed that they came from the disc and case. It is concluded that excessive vibration caused the wear and in zero gravity particles were free to migrate into the electrical contacts, resulting in a higher disc deflection to open the thermostat contacts. The result is a higher heater turn off temperature. | |
| language | English | |
| title | NASA-LLIS-0449 | num |
| title | Lessons Learned - Migration of Conductive Contaminates in an Electrical Switch in Zero "G" | en |
| type | standard | |
| page | 2 | |
| status | Active | |
| tree | NASA - National Aeronautics and Space Administration (NASA):;1990 | |
| contenttype | fulltext | |
| subject keywords | Hardware | |
| subject keywords | Parts Materials & Processes | |
| subject keywords | Test & Verification |