How many millisecond power interruption can a WS-6509-E ride through

[Douglas Cherry]

I am trying to determine how fast a transfer switch has to be able to operate to allow the equipment detailed below to ride though a power transfer. The existing ATS switch has a designed transfer time of 40 Milliseconds between UPS sources supplying the distribution panel supporting both power supplies.

The equipment being supported is a WS-6509-E with redundant WS-CAC-2500W power supplies.

[f00z]

What you are looking for is the "output holdup time" ; most devices are rated around 16ms. I believe the power supplies on the 6500 are 20ms, as hopefully confirmed by this. Most UPS units do 4-16ms range like your standard offline backup ups types. If it's not 100% load  the holdup time could be more and if it swaps at a certain point in the AC input cycle it could be more also, but the minmum guaranteed time it will stay up is 20ms if the docs are right on cisco's site.  So I would be weary going OVER the minimum of 20ms for the switchtime.   Worst case you could put an in-rack UPS on one of the power supplies to compensate

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/hardware/Chassis_Installation/Cat6500/6500_ins/0apwsply.html

[Douglas Cherry]

Thankyou f00z I appreciate the assistance.