Marine VMEbus systems breeze through 25g shock test

Given the applications, meeting exacting shock and vibration requirements was critical. Extensive Finite Element Analysis (FIA) confirmed that the systems would withstand 25g shock and vibration to MIL-STD-167.

The systems were all 19” 6U high, 180mm deep and either 42 or 84HP half/full width. The subracks are constructed from the KM6-HD front and rear extrusions mounted in special duplex stainless steel side plates to give the required rigidity and strength. The KM6-HD card guides are screwed down to the tiebar extrusions to further increase the stiffness of the unit.

The custom 5HP power supply modules plug in to the front of the subrack, interfacing with the backplane via rugged DIN 41612 H15 high power connectors. Each module contains two military grade converters, one providing stable, smoothed +5VDC, the other ±12VDC from the ship’s 28VDC supply. The half width systems are fitted with one module; the full width ones have two to support the increased current requirements of the larger system and to give an element of N+1 redundancy.

As part of the contract, Verotec also supplied mechanically identical 6U 84HP systems for onshore only use. The cost-reduced test units are constructed from the KM6-2 commercial grade subrack, two commercial grade plug-in switched mode PSUs and VMEbus backplane.