5.
Remove the plastic cable cover from the power input terminals by using the Phillips (+) screwdriver,
number 2, to loosen the screws (see
).
Figure 60: Remove the Plastic Cable Cover on a JNP10K-PWR-DC2 Power Supply
6.
Remove the nuts from each DC power input terminal, using the 13/32 in. (10 mm) nut driver or
socket wrench.
7.
Ensure that the power source circuit breaker is open so that the voltage across the DC power
source cable leads is 0 V. Also ensure that the cable leads don’t become active while you connect
DC power.
8.
Verify that the DC power cables are labeled correctly before making connections to the power
supply. In a typical power distribution scheme where the return is connected to chassis ground at
the battery plant, you can use a multimeter to verify the resistance of the –48 V and RTN DC
cables to chassis ground:
• The cable with very high resistance (indicating an open circuit) to chassis ground is negative (–)
and will be installed on the –48 V (input) DC power input terminal.
• The cable with very low resistance (indicating a closed circuit) to chassis ground is positive (+)
and will be installed on the RTN (return) DC power input terminal.
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