System Pressure
The High Voltage Unit is insulated with pressurized Sulfur Hexafluoride Gas (SF6). Every effort has been made to ensure a leak-tight system. The unit is pressurized to 30 psig when shipped and contains a relief valve set just above 30 psi. The unit is filled at sea level. Transportation in unpressurized aircraft, or in cargo holds with reduced pressure, may result in an increase in the differential pressure as compared to sea level (14.7 psi).
The High Voltage Unit is insulated with pressurized Sulfur Hexafluoride Gas (SF6). Every effort has been made to ensure a leak-tight system. The unit is pressurized to 30 psig when shipped and contains a relief valve set just above 30 psi. The unit is filled at sea level. Transportation in unpressurized aircraft, or in cargo holds with reduced pressure, may result in an increase in the differential pressure as compared to sea level (14.7 psi).
Failure Modes
Protective circuitry in the High Voltage Unit has been incorporated to suppress high voltage transients that may be generated under fault conditions. The anode current transmitter, under extreme operating conditions, can sustain damage. This would be evidenced by either saturation of the mA output signal, or a negative offset of 100 mV.
Loss of internal pressure will result in a decrease in the insulation properties of the internal gas (SF6) which could reflect itself as internal arcing between components, or to ground. This could result in the destruction of some semi-conductor elements.