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Installing a DC Power Supply on the SRX550 Services Gateway

 

To install a DC power supply:

  1. 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. To ensure that all power is off, locate the circuit breaker on the panel board that services the DC circuit, switch the circuit breaker to off position (O), and tape the switch handle of the circuit breaker in the off position.
  2. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist and connect the strap to one of the ESD points on the chassis. For more information about ESD, see Preventing Electrostatic Discharge Damage to the SRX550 Services Gateway.
  3. Orient the power supply so that the locking lever is on the left, as shown in Figure 1.
    Figure 1: Installing a DC Power Supply on an SRX550 Services Gateway
    Installing a DC Power
Supply on an SRX550 Services Gateway
  4. Using both hands, slide the power supply straight into the chassis until the power supply is fully seated in the chassis slot. The power supply faceplate should be flush with any adjacent power supply faceplate.
  5. Tighten the captive screws on the lower edge of the power supply faceplate.
  6. Remove the clear plastic cover protecting the terminal studs on the faceplate.
  7. 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 RTN DC cables to chassis ground:

    • The cable with very large resistance (indicating an open circuit) to chassis ground will be –48V.

    • The cable with very low resistance (indicating a closed circuit) to chassis ground will be RTN.

    Caution

    You must ensure that power connections maintain the proper polarity. The power source cables might be labeled (+) and (–) to indicate their polarity. There is no standard color coding for DC power cables. The color coding used by the external DC power source at your site determines the color coding for the leads on the power cables that attach to the terminals on the power supply.

  8. Connect DC power cables to the A+ and A- terminals:
    1. Remove the screws and square washers from the A+ and A- terminals. Use a Phillips (+) screwdriver, number 2. The square washers are permanently attached to the screws.
    2. Secure each power cable lug to the appropriate terminal with a screw. Apply between 23 lb-in. (2.6 Nm) and 25 lb-in. (2.8 Nm) of torque to each screw.
      • Secure the positive (+) DC source power cable lug to the A+ (return) terminal.

      • Secure the negative (–) DC source power cable lug to the A- (input) terminal.

    Figure 2: Connecting DC Power Cables
    Connecting DC Power Cables
  9. Replace the clear plastic cover over the terminal studs on the faceplate.
  10. Verify that the power cables are connected correctly, that they are not touching or blocking access to services gateway components, and that they do not drape where people could trip on them.
  11. Remove the tape from the switch handle of the circuit breaker on the panel board that services the DC circuit and switch the circuit breaker to the on position (  |  ). Observe the status LEDs on the power supply faceplate. If the power supply is correctly installed and functioning normally, the POWER LED lights green steadily on the services gateway front panel.
Note

If more than one power supply is being installed, turn on all power supplies at the same time.