Alternating current circuit breaker is suitable for reliable long-term service at 1000 deg F in the vacuum conditions of outer space. Construction materials are resistant to nuclear radiation and vacuum welding. Service test conditions and results are given

Edwards, R. N.

Travis, E. F.

English

NASA Technical Reports Server

December 1970
	 Brief 70-10721 
NASA TECH BRIEF H 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage commercial 
application. Tech Briefs are available on a subscription basis from the National Technical Information Service, Springfield, 
Virginia 22151. Requests for individual copies or questions relating to the Tech Brief progam may be directed to the Tech-
nology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
High Temperature Circuit Breaker 
An ac circuit breaker satisfies the design and operat-
ing criteria requiring components suitable for reliable 
long-term service at 1000°F in the vacuum conditions 
of outer space. Construction materials were selected 
for their resistance to nuclear radiation and vacuum 
welding. 
The circuit breaker was service tested to 1000°F in 
a vacuum of 10 6 torr for 2700 hours. Over 100 close/ 
open cycles were initiated under a 600A, 60Hz load. 
Subsequently, 32 close/open cycles were initiated with 
the current increased to 2400A in 200A steps. Finally, 
11 fault interruption tests were conducted in the range 
from 1800A (zero to peak) at 462V rms at interruption 
to 3750A at 960V, 950Hz. 
For current only, the tests were run at approximately 
50% above design rating; for power, a 40% over-
capacity was achieved. This power interruption 
capability amounts to 2.5MW on a single-phase basis, 
or 7.5MW on a three-phase basis. Closing times were 
25 milliseconds; opening times, 7 milliseconds *2 mil-
liseconds. All charts of the closing and opening times 
were essentially identical, showing excellent re-
peatability.
Notes: 
1. The following documentation is available from: 
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.65) 
Reference: 
NASA-CR-1719, Design, Performance, and 
Evaluation of an AC Breaker for Space Power 
Nuclear Electric Systems 
2. Technical questions may be directed to: 
Technology Utilization Officer 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio 44135 
Reference: B70-10721 
Patent status: 
No patent action is contemplated by NASA. 
Source: R. N. Edwards and E. F. Travis of 
General Electric Company 
under contract to 
Lewis Research Center, and 
E. A. Koutnik, L. A. Mueller and W. E. Snider 
Lewis Research Center 
(LEW-90265) 
Category 01 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned.rights.
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High temperature circuit breaker

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