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    Connect DC Power to a DC-Powered MX104 Router

    To connect power to the DC-powered router, you need the following tools:

    • Phillips (+) screwdriver, number 2
    • ESD grounding wrist strap
    • Grounding ring lug with hole sized for an M5 screw
    • M5 nut and washer (one per DC power supply, attached)
    • DC power source cables, minimum 14 AWG or as required by local code (not provided)
    • DC power ring lugs, Panduit PV12-14HDRB-2k (two per DC power supply)
    • M6 screws and washers (two per DC power supply, attached)
    • Grounding cable, use 6-AWG (13.3 mm2) 60° C wire for 24V DC (not provided)

    The DC power supply has two terminals on each power supply, covered by a clear plastic cover.

    Table 1: MX104 DC Power System Input Voltage

    Nominal Voltage

    Specification

    +24

    Operating range: +18 to +30 VDC

    –48

    Operating range: –39 to –56 VDC

    –60

    Operating range: –39 to –72 VDC

    1. Switch off the dedicated customer site circuit breakers. Ensure that the voltage across the DC power source cable leads is 0 V and that there is no chance that the cable leads might become active during installation.
    2. Ground the DC power supply (see Figure 10):
      1. Remove the nut and washer from the grounding point on the power supply.
      2. Secure each grounding cable lug to the grounding point with the washer and nut.

      Figure 10: Connecting the Ground Cable to the MX104 DC Power Supply

      Connecting the Ground Cable
to the MX104 DC Power Supply
    3. Remove the plastic cover protecting the terminal on the faceplate.
    4. Verify that the DC power cables are correctly labeled 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 –48V and return DC cables to chassis ground:

      For –48V and –60V:

      1. The cable with very high resistance (indicating an open circuit) to chassis ground is the DC input cable (-).
      2. The cable with very low resistance (indicating a closed circuit) to chassis ground is the return cable (+).

      For +24V:

      1. The cable with very low resistance (indicating a closed circuit) to chassis ground is the DC input cable (-).
      2. The cable with very high resistance (indicating an open circuit) to chassis ground is the return cable (+).
    5. Remove the screws and washers from the DC terminals.
    6. Secure each power cable lug to the terminal with the washers and screw (see Figure 11). Apply 27.4 lb-in. (3.1 Nm) of torque to each screw. Do not overtighten the screw. (Use a number 2 Phillips screwdriver.)
      1. Secure the positive DC source power cable lug to the return (+) terminal.
      2. Secure the negative DC source power cable lug to the input () terminal.

      Caution: Ensure that each power cable lug seats flush against the surface of the terminal block as you are tightening the screws. Ensure that each screw is properly threaded into the terminal. Applying installation torque to the screw when improperly threaded may result in damage to the terminal.

      Caution: The maximum torque rating of the terminal screws on the DC power supply is 27.4 lb-in. (3.1 Nm). The terminal screws may be damaged if excessive torque is applied. Use only a torque-controlled driver to tighten screws on the DC power supply terminals. Use an appropriately-sized driver, with a maximum torque capacity of 27.4 lb-in. or less. Ensure that the driver is undamaged and properly calibrated and that you have been trained in its use. You may wish to use a driver that is designed to prevent overtorque when the preset torque level is achieved.

    7. Replace the plastic cover over the terminals on the faceplate.
    8. Connect each DC power cable to the appropriate external DC power source.

      Note: For information about connecting to external DC power sources, see the instructions for your site.

    9. Switch on the external circuit breakers to provide voltage to the DC power source cable leads.
    10. Repeat Step 2 through Step 9 for the remaining power supply.
    11. Observe the LED on the power supply. The LED blinks green as it transitions online. If the power supply is functioning normally, the LED lights green steadily.

      If the LED is red or not lit, the power supply is not functioning normally. Repeat the cabling procedures.

    Figure 11: Connecting a DC Power Cable to an MX104 DC Power Supply

    Connecting a DC Power
Cable to an MX104 DC Power Supply

    Modified: 2016-04-11