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## Actual power consumption on WS-C6509-E

Beginner

Hello everyone,

I have a WS-C6509-E with two WS-CAC-6000W power supplies. I have to determine what is the real power consumption of the whole device but I noticed that there is a mismatch between measurements and show power output so I would very much appreciate if someone could explain why is that so.

I did the following test to try figure out the consumption from the power grid.

Step 1. When both supplies are active, show power gives me the following output:

C6509Test#show power

system power redundancy mode = redundant

system power total =     5771.64 Watts (137.42 Amps @ 42V)

system power used =      2253.72 Watts (53.66 Amps @ 42V)

system power available = 3517.92 Watts (83.76 Amps @ 42V)

Power-Capacity PS-Fan Output Oper

PS   Type               Watts   A @42V Status Status State

---- ------------------ ------- ------ ------ ------ -----

1    WS-CAC-6000W       5771.64 137.42 OK     OK     on

2    WS-CAC-6000W       5771.64 137.42 OK     OK     on

Pwr-Allocated  Oper

Fan  Type               Watts   A @42V State

---- ------------------ ------- ------ -----

1    WS-C6509-E-FAN      150.36  3.58  OK

Slot Card-Type          Watts   A @42V Watts   A @42V State State

---- ------------------ ------- ------ ------- ------ ----- -----

1    WS-X6748-GE-TX      325.50  7.75   325.50  7.75  on    on

2    WS-X6748-GE-TX      325.50  7.75   325.50  7.75  on    on

3    WS-X6748-GE-TX      325.50  7.75   325.50  7.75  on    on

4    WS-X6748-GE-TX      325.50  7.75   325.50  7.75  on    on

5    VS-S720-10G         338.10  8.05   338.10  8.05  on    on

6    VS-S720-10G         338.10  8.05   338.10  8.05  on    on

7    WS-X6724-SFP        125.16  2.98   125.16  2.98  on    on

system auxiliary power mode = off

system auxiliary power redundancy operationally = non-redundant

system primary connector power limit =   10920.00 Watts (260.00 Amps @ 42V)

system auxiliary connector power limit = 10500.00 Watts (250.00 Amps @ 42V)

system primary power used =              2253.72 Watts (53.66 Amps @ 42V)

system auxiliary power used =            0 Watt

Step 2. Then I switched off power supply 1:

C6509Test#

*Jan 22 09:29:21.753: %C6KPWR-SP-4-PSOUTPUTDROP: Power supply 1 output has dropp

ed

*Jan 22 09:29:21.769: %C6KPWR-SP-2-PSFAIL: power supply 1 output failed.

*Jan 22 09:29:21.769: %C6KPWR-SP-4-PSREDUNDANTONESUPPLY: in power-redundancy mod

e, system is operating on one power supply.

C6509Test#

C6509Test#show power

system power redundancy mode = redundant

system power redundancy operationally = non-redundant

system power total =     5771.64 Watts (137.42 Amps @ 42V)

system power used =      2253.72 Watts (53.66 Amps @ 42V)

system power available = 3517.92 Watts (83.76 Amps @ 42V)

Power-Capacity PS-Fan Output Oper

PS   Type               Watts   A @42V Status Status State

---- ------------------ ------- ------ ------ ------ -----

1    WS-CAC-6000W       3780.00 90.00  -      -      off

2    WS-CAC-6000W       5771.64 137.42 OK     OK     on

Pwr-Allocated  Oper

Fan  Type               Watts   A @42V State

---- ------------------ ------- ------ -----

1    WS-C6509-E-FAN      150.36  3.58  OK

Slot Card-Type          Watts   A @42V Watts   A @42V State State

---- ------------------ ------- ------ ------- ------ ----- -----

1    WS-X6748-GE-TX      325.50  7.75   325.50  7.75  on    on

2    WS-X6748-GE-TX      325.50  7.75   325.50  7.75  on    on

3    WS-X6748-GE-TX      325.50  7.75   325.50  7.75  on    on

4    WS-X6748-GE-TX      325.50  7.75   325.50  7.75  on    on

5    VS-S720-10G         338.10  8.05   338.10  8.05  on    on

6    VS-S720-10G         338.10  8.05   338.10  8.05  on    on

7    WS-X6724-SFP        125.16  2.98   125.16  2.98  on    on

system auxiliary power mode = off

system auxiliary power redundancy operationally = non-redundant

system primary connector power limit =   10920.00 Watts (260.00 Amps @ 42V)

system auxiliary connector power limit = 10500.00 Watts (250.00 Amps @ 42V)

system primary power used =              2253.72 Watts (53.66 Amps @ 42V)

system auxiliary power used =            0 Watt

Step 3. Now I disconnect the power input 1 on running power supply 2 thus leaving the device working on only one out of four power inputs:

C6509Test#

*Jan 22 09:35:50.297: %C6KPWR-SP-4-INPUTCHANGE: Power supply 2 input has changed

.  Power capacity adjusted to 2671.20W

*Jan 22 09:35:50.297: %C6KPWR-SP-4-PSOUTPUTDROP: Power supply 2 output has dropp

ed

C6509Test#show power

system power redundancy mode = redundant

system power redundancy operationally = non-redundant

system power total =     2671.20 Watts (63.60 Amps @ 42V)

system power used =      2253.72 Watts (53.66 Amps @ 42V)

system power available =  417.48 Watts ( 9.94 Amps @ 42V)

Power-Capacity PS-Fan Output Oper

PS   Type               Watts   A @42V Status Status State

---- ------------------ ------- ------ ------ ------ -----

1    WS-CAC-6000W       3780.00 90.00  -      -      off

2    WS-CAC-6000W       2671.20 63.60  OK     OK     on

Pwr-Allocated  Oper

Fan  Type               Watts   A @42V State

---- ------------------ ------- ------ -----

1    WS-C6509-E-FAN      150.36  3.58  OK

Slot Card-Type          Watts   A @42V Watts   A @42V State State

---- ------------------ ------- ------ ------- ------ ----- -----

1    WS-X6748-GE-TX      325.50  7.75   325.50  7.75  on    on

2    WS-X6748-GE-TX      325.50  7.75   325.50  7.75  on    on

3    WS-X6748-GE-TX      325.50  7.75   325.50  7.75  on    on

4    WS-X6748-GE-TX      325.50  7.75   325.50  7.75  on    on

5    VS-S720-10G         338.10  8.05   338.10  8.05  on    on

6    VS-S720-10G         338.10  8.05   338.10  8.05  on    on

7    WS-X6724-SFP        125.16  2.98   125.16  2.98  on    on

system auxiliary power mode = off

system auxiliary power redundancy operationally = non-redundant

system primary connector power limit =   10920.00 Watts (260.00 Amps @ 42V)

system auxiliary connector power limit = 10500.00 Watts (250.00 Amps @ 42V)

system primary power used =              2253.72 Watts (53.66 Amps @ 42V)

system auxiliary power used =            0 Watt

C6509Test#

*Jan 22 09:37:22.317: %C6KPWR-SP-4-INPUTCHANGE: Power supply 2 input has changed

.  Power capacity adjusted to 5771.64W

*Jan 22 09:38:58.523: %C6KPWR-SP-4-PSOK: power supply 1 turned on.

*Jan 22 09:38:58.535: %C6KPWR-SP-4-PSREDUNDANTBOTHSUPPLY: in power-redundancy mo

de, system is operating on both power supplies.

C6509Test#

Step 4. I used the current clamp to measure the current on the remaining power input and it reads 4.9 A.

When I multiply the current with voltage I get

P=4.9*230=1127 W.

So why does the show power output gives system power used = 2253.72 Watts, which is actually double value of measured 1127 W? What am I missing?

Thank you in advance for any help on this,

Marin

3 Replies 3
Beginner

hi marin_otto

your case is very similar to mine. I am trying to fetch a relation between actual power consumption and (CPU or BW) utilization; and another relation between actual power consumption and time.

best regards

Beginner

marin_otto.

Where are you located and what AC line voltage are you operating on (208 or 230v)?  I ran into your post and was wondering if you were operating on 208v which is line to line (two hots) and perhaps you are only measuring current on one line, effectively half the power.

Dave

Hi Dave and thanks for looking into this case.

I have a 230 V AC power source.

Marin

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