Wetting Power Distribution 24/48 V Dc - GE Mark VIeS System Manual

10.6.4.2 Wetting Power Distribution 24/48 V DC

The following I/O characteristics apply to the 24/48 V dc wetting power distribution section of the JPDG:
• Two 9-pin connectors (JPS1 and JPS2) are used for input. Each connector uses pins 1-4 for return and pins 6-9 for
positive 24/48 V dc to provide steady state current capacity of maximum 40 A. Pin 5 is not connected. Two redundant
power supplies feed a single power bus through external ORed diodes. A directly connected battery as wetting voltage
input is not supported. If a battery needs to be connected with the JPDG for wetting power, the required filter, upstream
fuse, and rectifier (all are the same used for the JPDE) must be properly installed and used.
• JP1 is the ground reference jumper. The dc bus is normally operated without a hard ground connection. The dc bus is
centered on earth as part of the ground fault detection scheme. Normally the 24 V dc positive terminal measures 12 V
above ground, and the negative terminal has the same magnitude below ground potential. Close jumper JP1 to use
onboard resistors to center the bus on earth, or JP1 is open when resistors are supplied externally to the JPDG or when
the JPDE is used with its JP1 jumper closed.
• There are seven (JFA through JFG) fused 2-pin Mate-N-Lok output connectors. They are fused for 15 A in both the lines.
Positive power is on pins 1 and negative power is on pins 2. Even though the fuses are of 15 A capacity, the actual
current drawn through each branch must not be more than 10 A at 55°C (131 °F); 8 A at 70°C (158 °F). The total current
drawn from JFA through JFG must not exceed 40 A steady state.
• Connector P4 is used to connect low-level signals capable of monitoring status switches on each 24/48 V dc power
supply and sending feedback signals to the PPDA. Pin 1 provides +10 V dc wetting to the status switch for supply 1, and
the return is on pin 3. For status switch on power supply 2, Pin 2 provides +10 V dc wetting, and the return is on pin 4.
380 GEH-6855_Vol_II GEH-6855_Vol_II Mark VIeS Functional Safety Systems Volume II
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