Technical Documentation
Maintaining the T1600 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 accumulating near the router. To review grounding and site wiring requirements for the router, see T1600 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 T1600 AC or DC Power Supply. To replace a side air filter, see Replacing a Side Air Filter on a T1600 AC Power Supply.
- Routinely check the LEDs on the DC power supply faceplates.
During normal operation:
- The blue DC OK LEDs light to indicate that the power supplies are functioning normally.
- Each green INPUT PRESENT LED on a DC power supply lights when the input is receiving source DC power.
- The green AC OK LED on an AC power supply lights when the power supply is receiving source AC power.
- Each CB ON LED on a DC power supply lights when the circuit breaker is on.
- 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 following CLI command:
user@host> show chassis alarms - 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 41 degrees C / 105 degrees F DC Input: OK DC Output Voltage Current Power Load FPC 0 56775 1362 77 10 FPC 1 57058 1318 75 10 FPC 2 57483 1293 74 9 FPC 3 57341 1318 75 10 FPC 4 57100 1381 78 10 FPC 5 57016 0 0 0 FPC 6 57000 0 0 0 FPC 7 56958 0 0 0 SCG/CB/SIB 56100 5975 335 27 PEM 1 status: State Present Temperature 33 degrees C / 91 degrees F DC Input: Check DC Output Voltage Current Power Load FPC 0 0 0 0 0 FPC 1 0 0 0 0 FPC 2 0 0 0 0 FPC 3 0 0 0 0 FPC 4 0 0 0 0 FPC 5 0 0 0 0 FPC 6 0 0 0 0 FPC 7 0 0 0 0 SCG/CB/SIB 0 0 0 0If 0 is displayed for the SCG/CB/SIB in the Current, Power, and Load fields for a PEM, and the voltage field does not match the other PEM, it might indicate a difference between the DC input voltages applied to PEM0 and PEM1. Consider checking your DC power network for unintended voltage drops to the router (see T1600 DC Power Distribution for a typical DC source cabling arrangement).
The 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 T1600 DC Power System Electrical Specifications .
- For the three-input 240-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 and INPUT 2 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 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 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 25For further description of the output from the commands, see the Junos OS System Basics and Services Command Reference
.
