Hello Girish,
From http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps7148/ps7130/prod_qas0900aecd805bbf21.html =>
Q. Can a device revert back to its own power supply without rebooting?
A. A Catalyst E Series switch is capable of reverting back to its own power supply without rebooting. All other devices might reboot when reverting back to their own power supplies.
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Q. Why does a device continue to draw power from the RPS even after its internal power is restored?
A. This is expected behaviour for all devices, other than the Catalyst E series switches. The device might reboot when reverting back to its own power supply. Hence, it continues to draw power from the RPS, so that the device can be switched back to its own power supply at a convenient time. In order to switch the device back to its own power supply, place the RPS port in "Standby" mode until the device reverts back to its own power supply, then place the RPS port in "Active" mode again. The Catalyst E Series switches are capable of reverting back to their own power supplies without service interruption.
Hope that helps.
Kind regards.
Karim