Operation Manual - Hobart 2400 Compact Power – 120 / 140 / 180 kVA
Transport and Installation
Document no. 578.430AB
Page 25 of 75
4.8
400 Hz Interlock
The interlock safety system ensures that the output contactor stays engaged as long as the aircraft
connector is inserted into the aircraft receptacle. The aircraft provides 28 VDC on the F terminal with
respect to the 400 Hz neutral terminal.
Fig. 4.8.1 Standard wiring diagram for civil aircraft
For service, maintenance and test purposes, the interlock system can be bypassed via the display active
status. To ensure personnel health and safety, the ground power unit automatically returns to its initial
interlock mode once it receives 28 VDC at the F terminal, e.g. when the ground power unit is connected
to an aircraft.
To ensure personnel health and safety, the interlock safety system must always be activated
unless the ground power unit is undergoing service, maintenance or test by qualified
personnel.
4.9
Control Interface (Remote I/O Terminals)
Using the Remote I/O terminals, situated behind the front door to the left, it is possible to interface to:
•
External Emergency Stop (EPO).
The external EPO input A2: X6 is a 24 VDC input, either by using the internal 24 VDC supply
or an external 24 VDC voltage. The SW1 “EPO JUMPER” (right hand side of the A2 Module,
close to X7/X10) is then removed. Please refer to Fig. 4.9.1 for connection.
•
E&F Interlock F Pin.
•
External Start/Stop.
Remote Start must be N.O. The remote Stop may be either N.O./N.C., this can be
selected/changed using the Set-Up menu.
•
90 % Switch/split “F” pin in aircraft connector.
The 90% switch (N.O. contact set) in the aircraft connector is supplied with +24 VDC from the
AXA 2400. The voltage is returned once the plug is inserted at least 90% of the way into the
aircraft receptacle.
•
Aircraft Connector temperature supervision.
The 3 x PTC resistors in series (one for each phase) is supplied with +24 VDC from the AXA
2400. They return a high signal (+24 VDC) to the input as long as the plug temperature is below
the PTC resistors cut-off value.
OM2252
Rev 0 December 15 2016
