Figure 12: Power Supply Assembly - GE P4A Technical Manual

Chapter 3 - Hardware Design

Figure 12: Power supply assembly

The power supply outputs are used to provide isolated power supply rails to the various modules within the unit.
Three voltage levels are used by the unit's modules:
5.1 V for all of the digital circuits
●
+/- 16 V for the analogue electronics such as on the input board
●
22 V for driving the output relay coils.
●
All power supply voltages, including the 0 V earth line, are distributed around the unit by the 64-way ribbon cable.
The power supply board incorporates inrush current limiting. This limits the peak inrush current to approximately
10 A.
Power is applied to pins 1 and 2 of the terminal block, where pin 1 is negative and pin 2 is positive. The pin
numbers are clearly marked on the terminal block as shown in the following diagram.
44
P54A/B/C/E
P54xMED-TM-EN-1