Applicability of the STK-RPS-xxxPS Redundant Power Supplies

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Article ID: 13569

Products
STK-RPS-1005PS, STK-RPS-500PS, STK-RPS-150PS
STK-RPS-1005CH3, STK-RPS-150CH2, STK-RPS-150CH8

Discussion
This document serves as a supplement to the information provided in 5741 ("Functionality of the SecureStack RPS Systems"), and outlines how these newer RPS components, released with the C5-Series and B5-Series, may and may not be used.

The STK-RPS-1005PS redundant power supply can only be used with the C5 PoE switches. It is very different from all other PoE supplies, so cannot be used with a C3, C2, B5, B3, B2, A4, or A2. It is a 1005 watt load-sharing 54 volt (IEEE802.3at PoE) power supply; load-sharing allows it to be used in additive mode as well as redundant mode (similar to the G3 power supplies). The connector for this RPS is very different from the connectors used for the other PoE RPS so there is no way this power supply could be accidentally connected to anything but a PoE C5 switch. It should be noted that the STK-RPS-1005PS requires a shelf in order to be rack-mounted. The STK-RPS-1005CH3 shelf can hold up to three STK-RPS-1005PS units in 1RU of space.

The STK-RPS-500PS redundant power supply is a 500 watt 54 volt (IEEE802.3at PoE) power supply that is for use with the B5 and A4 PoE switches. The connector on this power supply is the same as the connector used on the C2RPS-POE which is a 500 watt 48 volt (IEEE802.3af PoE) power supply. While the STK-RPS-500PS is not necessarily designed to be used with the older IEEE802.3af stackables (i.e. C3, C2, B3, B2, A2), being connected to the STK-RPS-500PS will not damage them. If you do connect a STK-RPS-500PS to one of these IEEE802.3af switches, there are two sets of expected behavior depending upon the product:

• With the C2, B2, and A2; the STK-RPS-500PS will automatically become the primary power supply for the switch while the internal supply will become the backup. This is due to the logic in the switches for selecting the power supply with the higher voltage as the primary supply.
• With the C3 and B3; the STK-RPS-500PS will automatically become the primary power supply for the switch (for the reason explained above) but the internal supply will not become the backup. This is because the over-voltage protection of the internal power supply will kick in when it senses the additional voltage (6 volts higher) of the RPS. The only way to get the internal power supply out of the over-voltage protection mode is to remove power to the switch and reboot it without the RPS being present.

The STK-RPS-500PS ships with rack-mount ears and requires 1RU of space per RPS.

The existing C2RPS-POE redundant power supply is a 500 watt 48 volt (IEEE802.3af PoE) power supply that is for use with the C3, C2, B3, B2, and A2 PoE switch models. It should never be used with the B5 or A4 PoE switches since it will not deliver the appropriate voltage to drive high power IEEE802.3at (30 watts per user) over 100 meters. Connecting a C2RPS-POE to a B5 or A4 will not damage it. The internal B5/A4 power supply will remain primary and the C2RPS-POE will only be used if the internal power supply fails, as expected. But, if the internal power supply does fail, the combination of a B5/A4 with a C2RPS-POE may not be able to deliver the required power over a maximum length cable.

The STK-RPS-150PS (renamed from the old C2RPS-PSM) redundant power supply is a 150 watt 12 volt power supply that is for use with the C5, C3, C2, B5, B3, B2, A4, and A2 non-PoE switch models. The STK-RPS-150PS connector is keyed differently than the 500 watt PoE power supplies so a non-PoE RPS cannot be inadvertently connected to a PoE switch and a PoE RPS cannot be inadvertently connected to a non-PoE switch. Please note that the old C2RPS-PSM part number will be end of sale on December 30, 2010 so the STK-RPS-150PS will be the only non-PoE power supply for all non-PoE stackables.

It should also be noted that the non-PoE RPS shelves (C2RPS-CHAS2and C2RPS-CHAS8) have been retired and replaced with the STK-RPS-150CH2 two-slot 1RU shelf and the STK-RPS-150CH8 eight-slot 5RU shelf. The two new shelves can support either of the non-PoE RPS power supplies; the old C2RPS-PSM or the new STK-RPS-150PS.