Maintaining the T640 Power Supplies
Purpose
For optimum router performance, verify the condition of the power supplies.
Action
On a regular basis:
- Make sure that the power and grounding cables are arranged so that they do not obstruct access to other router components.
- The power supplies require an unobstructed airflow at both the front and rear of the chassis. Periodically check the site to ensure that both the air intake at the bottom front of the chassis and the exhaust from the power supply faceplates are unobstructed.
- Periodically inspect the site to ensure that the grounding and power cables connected to the router are securely in place and that no moisture is accumulating near the router. To review grounding and site wiring requirements for the router, see T640 Chassis Grounding Cable and Lug Specifications and Site Electrical Wiring Guidelines for M Series and T Series Routers.
- Regularly inspect the air filters on each power supply for dust and debris, and replace the side filter on AC power supplies or front filter element on AC and DC power supplies every 6 months. To replace a power supply front air filter element, see Replacing a Front Air Filter Element on a T640 AC or DC Power Supply. To replace a side air filter, see Replacing a Side Air Filter on a T640 AC Power Supply .
- Routinely check the LEDs on the DC power supply faceplates. If the DC OK LEDs are lit steadily, the power supplies are functioning normally.
- Routinely check the LEDs on the AC power supply faceplates. If the AC OK LEDs are lit, the AC terminal blocks are receiving power. If the DC OK LEDs are lit, the AC power supplies are functioning normally.
- Check the red and yellow alarm LEDs and the LCD on the
craft interface. Power supply failure or removal triggers an alarm
that causes one or both of the LEDs to light and an error message
to appear on the LCD. You can display the associated error messages
by issuing the CLI command:
user@host> show chassis alarmsFor a list of possible alarm messages, see Troubleshooting Using the T640 Chassis and Interface Alarm Messages.
- Issue the show chassis environment pem command to check the status of the power supplies. For DC- powered
routers, the output is similar to the following:
user@host> show chassis environment pemPEM 0 status: State Online Temperature 24 degrees C / 75 degrees F DC Input: OK DC Output Voltage Current Power Load FPC 0 0 0 0 0 FPC 1 54558 981 53 7 FPC 2 54558 2800 152 20 FPC 3 54700 2225 121 16 FPC 4 54375 2387 129 17 FPC 5 54308 3543 192 25 FPC 6 54558 1287 70 9 FPC 7 54616 2650 144 19 SCG/CB/SIB 54150 181 9 0PEM 1 status: State Online Temperature 23 degrees C / 73 degrees F DC Input: OK DC Output Voltage Current Power Load FPC 0 0 0 0 0 FPC 1 50691 0 0 0 FPC 2 50766 0 0 0 FPC 3 50725 0 0 0 FPC 4 50725 0 0 0 FPC 5 50766 0 0 0 FPC 6 50808 0 0 0 FPC 7 50625 0 0 0 SCG/CB/SIB 50300 0 0 0The current sharing between DC power supplies relies on equal voltages at the input terminals of the power supplies. However, if the voltages do not match, the router operates normally as long as the DC input voltages are within the operating range provided in T640 DC Power System Electrical Specifications .
- For the three-input 240-A DC power supplies in 2–INPUT mode and the two-input 160-A DC power supplies, system power is divided into two load zones. One load zone consists of INPUT 0 of PEM0 and PEM1. The other load zones consist of INPUT 1 of PEM0 and PEM1. Load sharing occurs between the two power supplies for each load zone. Therefore, the input voltage for the inputs in each load zone must be equal in both power supplies for current sharing. For example, the input voltage for INPUT 0 of PEM0 and the input voltage for INPUT 0 of PEM1 must be the same for current sharing to occur within that load zone.
- For the four-input 240-A DC power supplies, system power is divided into four load zones. One load zone consists of INPUT 0 of PEM0 and PEM1. The three other load zones consist of INPUT 1, INPUT 2 and INPUT 3 of PEM0 and PEM1. Load sharing occurs between the two power supplies for each load zone. Therefore, the input voltage for the inputs in each load zone must be equal in both power supplies for current sharing. For example, the input voltage for INPUT 0 of PEM0 and the input voltage for INPUT 0 of PEM1 must be the same for current sharing to occur within that load zone.
For further description of the output from the commands, see the Junos System Basics and Services Command Reference.
For AC-powered routers, the output is similar to the following:
user@host> show chassis environment pemPEM 1 status: State Online Temperature 33 degrees C / 91 degrees F AC Input: OK DC Output Voltage(mV) Current(mA) Power(W) Load(%) FPC 0 55183 7056 389 51 FPC 1 55633 7018 390 52 FPC 2 55533 5187 288 38 FPC 3 55533 7081 393 52 FPC 4 55508 6612 367 48 FPC 5 55791 7337 409 54 FPC 6 55675 2593 144 19 FPC 7 55608 7600 422 56 SCG/CB/SIB 55308 5600 309 25
Related Topics
- T640 Two-Input 160-A DC Power Supply LEDs
- T640 Three-Input 240-A DC Power Supply LEDs
- T640 Four-Input 240-A DC Power Supply LEDs
- T640 Three-Phase Delta and Wye AC Power Supply LEDs
- Troubleshooting the T640 Power System
- General Electrical Safety Guidelines and Electrical Codes for M Series, MX Series, and T Series Routers
