The Raritan Blog


Posted on November 20, 2017 by Yeou-Shiuh  |  Comment (0)

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William Nelson wrote on 07/16/09:

Hi James

john wrote on 08/13/09:

Has anyone heard of Green Collar Operations?

I received a notice from them. I guess they work with Austin Energy and help process the rebates for energy efficiency measures like radiant barrier, insulation, weatherization etc. Looking for some feedback

lee wrote on 10/10/09:

I wonder if voltage optimisation across the power supply would also cut energy costs.

raritan wrote on 06/25/10:

case studies sounds good

please email me some ppt.

.(JavaScript must be enabled to view this email address)

thank you

Dorothy Ochs wrote on 07/10/10:

Hello. Raritan’s client case studies are posted online at The client case studies that Raritan is speaking about at the DCD San Francisco show include JR Simplot, eBay and Microsoft to name a few. The only one of those clients that formally has a case study written already is JR Simplot. That case study can be found at

I’d be happy to share a copy of the presentation with you after the show.

Steve Chambers wrote on 08/26/10:

Hi Allen, would love to see your numbers some day.  What Cisco’s competitors always fail to measure is the impact of their/our technology across the data center: ie. especially the impact on network gear.

If you scale UCS out to 112 blades then you will only need the two fabric interconnects verses ten times as many switches that competitors need.  All those ports and switches suck up power, as we know, but nobody (apart from Cisco) seems to do that math.


Looking forward to seeing more,


Nicole Espasa wrote on 09/15/10:

The link should work now, please let me know if you’re still having probelems accessing the firmware.

September 16 Thermal Management Industry Summary & wrote on 09/16/10:

[...] Raritan has published a new blog post titled, “It’s NOT about the Aisles, it’s about the I…      Tags electronics cooling, thermal management Categories News [...]

Allen Yang wrote on 10/22/10:

I wrote on this blog last time that Raritan IT will monitor the incremental power consumption of the Cisco UCS we deployed, while we gradually migrate some rack-mount physical servers as VMs onto the UCS blades.  The following results reflect our migration activities between 2010-08-05 and 2010-10-20.  We have 2 UCS chassis that we call UCS1 and UCS2, and both of them are installed on our Cisco Rack 4.  During the time period from 08/05 to 10/20, we had the following physical activities:

08/11: Turn on two blades on UCS for engineering testing

08/15: Turn on 2nd 10Gib port on Fabric Interconnect

08/30: Remove 2 VMware ESX Servers (2 Dell PowerEdge 1950)

09/01: Turn 1 additional blade on UCS2 to measure its effect on power consumption

09/03: Remove SharePoint Test Server (a Dell PowerEdge 2850) and DNS2 (a 1U PC-server)

09/14: Migrate BES as a VM onto UCS blade (an HP Proliant DL140)

09/20: Migrate Exchange Server (a Dell PE1950) as a VM onto UCS blade; turn testing blade off

10/11: Turn one UCS blade on for Oracle JDE remote DR site


From Power IQ data reading we have the following observations:


1. Each UCS blade we have consumes roughly 4.3 KWh per day.  This is somewhat consistently demonstrated from measuring the total power consumption of the observed systems including the 2 UCS chassis and the non-UCS physical servers.  On 08/11, the measurement was 334.6 KWh.  On 08/12, 24-hours later after turning on 2 UCS blades, the measurement was 339.7KWh.  Since then the UCS power consumption stayed at that level until the next even on 08/15.  This 4.3KWh incremental power consumption per UCS blade per day was also consistently measured between 09/01 and 09/02 when IT turned on the 3rd blade on UCS2 to measure incremental power consumption.


2. Migrating mildly loaded physical rack-mount servers as VMs onto the UCS blades typically doesn’t increase much power consumption.  We Installed VMware ESX host on UCS and migrated two physical application servers onto UCS blade, and we couldn’t even find material difference before and after adding these 2 VMs onto UCS.  But the power savings from decommissioning physical servers can be clearly seen.  On 08/30, we removed 2 ESX host physical servers (Dell PowerEdge 1950), the total power consumption dropped by 6.55KWh a day.  Then on 09/03, we removed another PowerEdge 2850 (a Sharepoint test Server) and a 1-U PC server (DNS); and we saw a drop of power consumption by 7.2KWh a day.  Therefore, we see a clear power saving advantage from migrating physical servers into VMs.


3. The new version of Power IQ is very helpful in data exporting and giving power consumption insights at various levels of details.  We captured several diagrams from Power IQ to see the trend over time, then right from there we export the data into Excel spreadsheet, and we can examine the day by day details in there.

Charlette Reaux wrote on 10/23/10:

Long time reader / first time poster. Really enjoy reading the blog, keep up the good work. Will most definitely start posting more in the future.

Rick wrote on 11/05/10:

Will there be a demo VM of dcTrack?

Henry Hsu wrote on 03/14/11:


Raritan now has multiple instances of dcTrack available in a hosted / cloud environment (as virtual machines) for customer demos. Please contact your Raritan sales representative (or email .(JavaScript must be enabled to view this email address)) to arrange for access to one.

Dave Clark wrote on 03/21/11:


  This is very useful.  Any possibility you can do same thing for 415/240v 3-phase strips?

paula wrote on 03/21/11:

Thank you!!  This clear language explanation was just what I needed & had been unable to find anywhere.  Expecting the 3-phase calculator to be equally helpful.  And the non-pushy plug for Raritan is well-written & effective grin

Henry Hsu wrote on 04/07/11:

Hi Dave,

The reason I didn’t create a 415V version—even though we have an extensive line of 415V power strips both in the U.S. and internationally—is because unlike the 208V 3-phase strips, 415V 3-phase arithmetic is straightforward. This is because 415V power strips are wired “line-to-neutral”, otherwise known as “3-phase WYE”.

What that means in English is that any given outlet only affects a single line. Each circuit will be one of the following:

L1 to Neutral: Servers on these outlets place their load directly on L1
L2 to Neutral: Servers on these outlets place their load directly on L2
L3 to Neutral: Servers on these outlets place their load directly on L3

So to find out how much current is on L1, you just add up the current from all the servers on the one circuit. Unlike a 208V 3-phase power strip, the rest of the servers on the power strip do not affect L1 at all. This is a remarkably convenient truth about 415V power distribution, and one of the reasons some of my biggest clients are using 400V 3-phase distribution to the cabinet.

Let me know if that is unclear in any way.

3-Phase Balancing Act « Virtually From Scrat wrote on 06/07/11:

[...] happen to like the Raritan 3Ø Rack PDU Calculator and Henry Hsu does a great job of explaining the understanding problem on their blog. The Excel spreadsheet they provide is straightforward to use and does all the pertinent math for [...]

Wish to remain anonymous wrote on 07/11/11:

This spreadsheet incorrectly utilizes what seems to becoming known as the Oregon Fudge Factor. This factor is in reality the power that could become available to us in a reactive load is as a result of the phase angle difference between the phases in a 3 phase system. In a 3 phase system, the additional power that becomes available to us is 1.732, the square root of 3. In a 208v single phase (polyphase) circuit, the additional power that could become available to us in a reactive load (not resistive load) is 2/square root of 3 or 1.15470054. So you are incorrectly subtracting it from the sum of single phase load and not adding it to the 208v polyphase circuit.

Walt Stevens wrote on 09/01/11:

Hello, wonderful calculator.  It is helping with my project with a 60 amp(48 amp) 17.3 KVA PDU.  I have one twist in that this PDU also has and additional 120v NEMA 5-15 receptacle which uses Phase X to Neutral. 

Any suggestions on how to get a better estimate of Phase X amperage with this additional outlet on the PDU. ?

How would this 115V output on Phase X upset the phase balance. 


Bob wrote on 09/26/11:

The calculation for the L1 “Capacity Remaining” for the two 60A sheets are using the incorrect breaker values. They are using 40, but should be 45 and 48. Is it possible to add a sheet for a 100A feed?

chris wrote on 09/27/11:


I wonder if you can help ?


We are doing some rough non invasive monititoring in factory.


We can calibrate the monitor units for UK single phase power, but will only be putting a clamp on one of the phases on the 3 phase - I know there are inaccuracies but what would be an appropriate multiplier factor for the power in a 415V 3 phase system top give teh power in this?





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