Shock Performance of a Shipboard Electrical Switchgear
TOWSON LABS INC BALTIMORE MD
Pagination or Media Count:
Shipboard circuit breakers are required to be shock-certified on the Lightweight Shock Machine LWSM. In spite of this, breakers sometimes malfunction during ship shock tests or shock tests of switchgear assemblies on the Mediumweight Shock Machine MWSM. In the study described here, a total of 27 AQB circuit breakers were tested on the LWSM, their performance notes and the shock environments to which they were exposed measured. The same breakers were then installed in a typical shipboard switchgear which was tested on the MWSM, and again the performance of the breakers noted and their shock environments measured. Initially, almost all of the breakers malfunctioned on the LWSM, opening or tripping from the closed position. After some modification and adjustment, a majority of them passed the LWSM test, although some did not. None malfunctioned when installed in the switchgear or the MWSM. Comparison of shock enviroments in terms of peak acceleation indicated the LWSM environment to be several times as severe as the MWSM environment. It appears that the LWSM test is successful in its intended role as a screening test, so that breakers which pass can be relied on to operate properly during MWSM or ship shock tests. It also appears that breaker malfunction during LWSM tests can be substantially eliminated by proper setting of internal adjustments andor minor modifications.
- Electrical and Electronic Equipment
- Marine Engineering