HA Series 
This series of vacuum contactors includes heavy and very heavy duty types normally used at 400 to 2,000 amps continuous and 4,000 to 28,000 amps AC interrupt. Some are also used in conjunction with higher current shunt switches to give continuous duty as high as 36,000 amps RMS where only moderate current is present during interruption. Some types are also used for higher current DC interruption aided by a counter-pulse system which creates artificial current zeros across the contacts during contact parting. Up to 40,000 amps DC at 40,000 volts has been interrupted by this method.


Units in this series have mechanical lives from 10,000 operations to over 3 million operations depending on contact spacing and opening speed. Most of the HA series uses contacts made of copper alloy with a refractory metal base to minimize erosion rate. This combination of materials provides minimum welding, minimum current chopping and rapid recovery rate of high dielectric strength after interruption.

Several units have a type of copper alloy without refractory metal which provides lower contact resistance and high interruption ratings but allows a higher erosion rate. Very high speed crobarring and current interrupting models are also available with contact parting time of 1 to 6 milliseconds and contact closing times as short as 2 to 8 milliseconds when used in conjunction with Ross Engineering SCR controlled stored energy drivers.


Specifications are for reference only and are subject to change.
Contact Ross Engineering Corp. for current information.

Detailed Information

HA Series

HB & HBDC Series