Technical Documentation
T640 DC Power System Requirements
To allow for future growth so that you can operate the T640 router in any hardware configuration without upgrading the power infrastructure, we recommend that you provision the following per each input. Doing so enables you to operate the router in any configuration without upgrading the power infrastructure.
- 68 A @ –48 VDC (nominal) for each power supply input on a two-input 160-A DC power supply
- 67 A @ –48 VDC (nominal) for input 0 and 67 A @ –48 VDC for input 1 on a three-input 240-A DC power supply
- 50 A @ –48 VDC (nominal) for each power supply input on a four-input 240-A DC power supply
If you do not plan to allow for future growth, you can use the information in Table 1 to calculate the typical power consumption @ –48 VDC and typical thermal output for your current hardware configuration. Table 1 lists the power requirements for various hardware components when the router is operating under typical voltage conditions.
Table 1: T640 Component DC Power Requirements
Component | Current Requirement (Amps @ –48 VDC) |
|---|---|
Base system, not including FPCs and PICs (includes five SIBs, one host subsystem, one SCG, cooling system, and craft interface), and two DC power supplies | 16.9 A |
SIB: Standard SIB, standard SIB version B, or T640-SIB | 0.8 A |
Enhanced FPC1 and Enhanced II FPC1 | 3.4 A |
Enhanced Scaling FPC1 | 7.1 A |
FPC2, Enhanced FPC2, and Enhanced II FPC2 | 3.4 A |
Enhanced Scaling FPC2 | 7.5 A |
FPC3, Enhanced FPC3, and Enhanced II FPC3 | 6.8 A |
Enhanced Scaling FPC3 | 9.1 A |
Type 4 FPC | 8.2 A |
T640 Enhanced Scaling FPC4-1P | 7.0 A |
Host subsystem (Routing Engine and control board) | 2.6 A |
SCG | 0.2 A |
Power supply | 1.7 A |
Cooling system (normal speed) | 6.7 A |
Cooling system (full speed) | 22 A |
Craft interface | 0.2 A |
PIC—Generalized typical value | 0.625 A |
PIC (Type 3)—Generalized maximum value | 1.2 A |
PIC (Type 4)—Generalized maximum value | 3.3 A |
These examples use generalized values for PICs. For PIC power
requirements, see the T640 Core Router PIC Guide 
.
- Example of calculating
power consumption for a minimum configuration under typical voltage
conditions:Base System + 1 FPC3 + 1 PIC =16.9 A + 6.8 A + 0.625 A = 24.3 A @ –48 VDC = 1,166 W
- Example
of calculating power consumption for a maximum configuration under
typical voltage conditions:Base System + 8 Enhanced Scaling FPC3 + 1 Host + 1 SCG + 32 PICs =16.9 A + 8(9.1 A) + 2.6 A + 0.2 A + 32(1.2 A) =16.9 A + 72.8 A + 2.6 A + 0.2 A + 38.4 A = 130.9 A @ –48 VDC = 6283 W
- Current
requirement adjustment for fans running at full speed (high temperature
environment or cooling component failure):Calculated system current (X) – Cooling (normal) + Cooling (full speed) =X A – 6.7 A + 22 A = X A + 15.3 A
- Input
current from a DC source other than –48 VDC (based on maximum
configuration):(–54 VDC input) x (input current X) = (–48 VDC) x (input current Y)54 x X = 48 x 94.1 AX = 48 x 94.1 A/54 = 83.6 A
- Example
of calculating system thermal output:Watts DC/0.293 = BTU/hr6283/0.293 = 21,444 BTU/hr
