MX240 Power Planning

The following tables list the MX240 component power requirements.Table 1 lists the MX240 base system power requirements. Table 2 lists the Switch Control Board (SCB) power requirements. Table 3 lists the FRU power requirements for Routing Engines, Modular Port Concentrators (MPCs), Modular Interface Cards (MICs), and Dense Port Concentrators (DPCs).

The information in this topic helps you determine which power supplies are suitable for various configurations, as well as which power supplies are not suitable because output power is exceeded. You determine suitability by subtracting the total power draw from the maximum output of the power supplies. Afterward, the required input power is calculated. Finally, you calculate the thermal output. A sample configuration is provided in Table 4.

We recommend that you provision power according to the maximum input current listed in the power supply electrical specifications (see AC Power Supply Electrical Specifications for the MX240 Router and DC Power Supply Electrical Specifications for the MX240 Router).

Use the following procedures to calculate the power requirement:

1. Calculate the power requirement.

2. Evaluate the power budget.

3. Calculate input power.

4. Calculate thermal output (BTUs) for cooling requirements.

The following sample configuration shows an MX240 router with:

• Two 16-port 10-Gigabit Ethernet MPCs with SFP+

• Two SCBs with two (redundant) RE-1800x2 routing engines

• High-capacity cooling system

  Note:

  The high-capacity cooling system satisfies cooling requirements of MPCs, and must be used for proper cooling.

1. Calculate the power requirements (usage) using the values in Power Requirements for an MX240 Router as shown in Table 4.

   Table 4: Sample Power Requirements for an MX240 Router

   Chassis Component	Part Number	Power Requirement
   Base system	MX240BASE-AC-HIGH	40 W
   High-capacity cooling system	FANTRAY-MX240-HC	85 W
   MPC - Slot 2 -	MPC-3D-16XGE-SFPP-R-B	440 W
   MPC - Slot 1	MPC-3D-16XGE-SFPP-R-B	440 W
   SCB 1/Slot 0	SCBE2-MX with RE-S-1800X2-8G	185 W 90 W
   SCB 0	SCBE2-MX with RE-S-1800X2-8G	185 W 90 W
   Total output power		1555 W
   Output power excluding cooling system		1470 W

2. Evaluate the power budget. In this step, we check the total output power against the maximum output power of available power supply options.

   Note:

   The power for the cooling system comes from a different tap on the power supply, reserved for the cooling system only. The cooling system power requirement does not need to be deducted from the output power budget of the power supply.

   Table 5 lists the power supplies, their maximum output power, and unused power (or a power deficit). See DC Power Supply Electrical Specifications for the MX240 Router and AC Power Supply Electrical Specifications for the MX240 Router for more information about the MX240 power supply electrical specifications.

   Table 5: Calculating Power Budget

   Power Supply	Maximum System Output Power	Unused Power1
   MX240 AC Normal-capacity (low-line)	2054 W	654 W
   MX240 AC Normal-capacity (high-line)	1590 W	190 W
   MX240 AC High-capacity (low-line)	2334 W	934 W
   MX240 AC High-capacity (high-line)	2050 W	650 W
   MX240 DC Normal-capacity	1600 W	200 W
   MX240 DC High-capacity (DIP=0)	2400 W	1000 W
   MX240 DC High-capacity (DIP=1)	2600 W	1200 W

   ¹ For this configuration, output power excluding the cooling system is 1400 W.

3. Calculate input power. In this step, the input power requirements for the example configuration are calculated. To do this, divide the total output requirement by the efficiency of the power supply as shown in Table 6.

   Table 6: Calculating Input Power Examples

   Power Supply	Power Supply Efficiency1	Input Power Requirement2
   MX240 AC Normal-capacity (high-line)	85 %	1747 W
   MX240 AC High-capacity (high-line)	89 %	1669 W
   MX240 DC Normal-capacity	~98 %	1515 W
   MX240 DC High-capacity	~98 %	1515 W

   ¹ These values are at full load and nominal voltage.

   ² For this configuration, total power is 1485 W.

4. Calculate thermal output (BTUs). To calculate this, multiply the input power requirement (in watts) by 3.41. See Table 7.

   Table 7: Calculating Thermal Output

   Power Supply	Thermal Output (BTUs per hour)
   MX240 AC Normal-capacity (high-line)	1747 * 3.41 = 5957 BTU/hr
   MX240 AC High-capacity (high-line)	1669 * 3.41 = 5576 BTU/hr
   MX240 DC Normal-capacity	1515 * 3.41 = 5166 BTU/hr
   MX240 DC High-capacity	1515 * 3.41 = 5166 BTU/hr