nanog mailing list archives
Re: Want to move to all 208V for server racks
From: Lamar Owen <lowen () pari edu>
Date: Sat, 4 Dec 2010 11:05:56 -0500
On Friday, December 03, 2010 02:54:37 am Chuck Anderson wrote:
Here's a question for you. How do you calculate the total current & power capacity of a L21-20 or L21-30, and how do you do the calculations in order to balance the load between the phase legs? This seems like it would be a trivial thing to do, but given that the three legs are 120 degrees out of phase with each other, I don't think you can just do normal addition.
You would be correct. A pretty good three-phase calculation reference can be found at http://www.3phasepower.org/3phasepowercalculation.htm It is vector addition, and with the angles involved you end up multiplying and dividing by the square root of 3 a lot. Also see the wikipedia article, and here's a few others: http://www.gavinelectrical.com/content/threephase.htm http://www.servertech.com/uploads/documents/0000/0236/3-Phase_Power_in_the_Data_Center.pdf That last PDF is directly related to this discussion, and a good read.
Current thread:
- Re: Want to move to all 208V for server racks, (continued)
- Re: Want to move to all 208V for server racks Jameel Akari (Dec 02)
- Re: Want to move to all 208V for server racks Seth Mattinen (Dec 02)
- Re: Want to move to all 208V for server racks William Herrin (Dec 02)
- Re: Want to move to all 208V for server racks Jameel Akari (Dec 02)
- Re: Want to move to all 208V for server racks Owen DeLong (Dec 02)
- Re: Want to move to all 208V for server racks Lamar Owen (Dec 02)
- Re: Want to move to all 208V for server racks Jeremy Bresley (Dec 02)
- RE: Want to move to all 208V for server racks Alex Rubenstein (Dec 02)
- Re: Want to move to all 208V for server racks Chuck Anderson (Dec 02)
- Re: Want to move to all 208V for server racks Gary Buhrmaster (Dec 03)
- RE: Want to move to all 208V for server racks Alex Rubenstein (Dec 03)
- Re: Want to move to all 208V for server racks Lamar Owen (Dec 04)
- Re: Want to move to all 208V for server racks Chuck Anderson (Dec 02)
- Re: Want to move to all 208V for server racks Kevin Stange (Dec 02)
- Re: Want to move to all 208V for server racks Christopher Phillips (Dec 02)
- Re: Want to move to all 208V for server racks William Pitcock (Dec 02)
- Re: Want to move to all 208V for server racks Gary Buhrmaster (Dec 03)
- RE: Want to move to all 208V for server racks Alex Rubenstein (Dec 03)
- RE: Want to move to all 208V for server racks David Hubbard (Dec 02)
- Re: Want to move to all 208V for server racks Jay Nakamura (Dec 02)
- Re: Want to move to all 208V for server racks Mark Kent (Dec 02)
- Re: Want to move to all 208V for server racks Ingo Flaschberger (Dec 02)
- Re: Want to move to all 208V for server racks Seth Mattinen (Dec 02)