3Com 5500-EI Getting Started Guide - Page 38

38 CHAPTER 2: INSTALLING THE SWITCH Specifying the 3Com's redundant power solution allows you to use any off-the-shelf Redundant Power -48V DC RPS that meets the requirements defined in Appendix C on System page 127. For an approved vendor list, more details about purchasing the 3Com recommended RPS, and a full set of requirements go to: http://www.3Com.com/RPS The 3Com recommended RPS generates -48V DC power using power supply units (or rectifiers). The outputs of the rectifier(s) are connected together so that you can increase the total -48V power available by adding rectifiers. For example, three 1500W rectifiers can provide up to 4500W. Hot removal or insertion of a rectifier does not affect the -48V DC output voltage. Table 14 shows an example of the total power available from several 1500W rectifiers. A minimum of two rectifiers are required for each shelf to provide N+1 rectifier redundancy. Table 14 Power Availability No Rectifier Redundancy N+1 Rectifier Redundancy 1 2 1500W 3000W - 1500W Rectifiers 3 4500W 4 6000W 3000W 4500W 5 6 7500W 9000W 6000W 7500W The unearthed -48V DC power distribution provides the mechanism to connect to the Switch 5500. The distribution consists of several circuit breakers and connection terminals for the positive (common) and negative -48V outputs. Individually connect each Switch 5500 to a circuit breaker terminal. You can also connect a battery to battery terminals prior to the DC power distribution to provide uninterrupted power and to be protected against the loss of AC mains power.