U L T R A F L E X H D P D U U S E R M A N U A L
3.9.1.2
48V DC Power Fault
The 48V DC power fault is a common fault signal for all the 48V power supplies installed in the system. The
fault signals of all the power supplies are tied together so any single fault will generate a 48V DC power fault
signal. The 48V DC power fault will also be generated when no rectifiers are installed. Rectifier good LED’s
are provided for visual indication of a failed power supply. The 48V DC power fault output is the transistor
side of an optocoupler. Maximum recommended current draw through the optocoupler is 3mA. A 48V DC
power fault will be active when the 48V bus is disabled or when any of the power supplies have failed.
3.9.1.3
DC current monitor
The interface PCB provides a DC current monitor signal to the SMC controller. The current monitor signal is
designed to produce 2.7V across a 158 Ohm resistor with a load of 300A. Refer to
DC current monitor signal for various load conditions.
Current Monitor Signal (4 rectifiers installed)
0
0.5
1
1.5
2
2.5
3
0
25
50
75
100
125
150
175
200
225
250
275
300
DC Load (A)
Current Monitor (V)
I mon
Graph 2 – Current monitor signal vs. load graph
708401 Rev B
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