During the energy crises in the 70s we went to 110/220. The we may be the west coast. Some places I have measured as low as 90V. This tends to make things malfunction.
-----Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED] Behalf Of Phil Howard Sent: Wednesday, March 16, 2005 9:49 AM To: LINUX-390@VM.MARIST.EDU Subject: Re: electrical power - Was: Re: Debian touts dropping full dev for certain archit ectures (incl. S/390) On Wed, Mar 16, 2005 at 10:57:44AM -0500, Henry Schaffer wrote: | Even if 208 (derived from 3 phase service) and 220/240 (the normal | single phase service found in homes and small businesses) are all | not-too-far-apart, so that many times one can ignore the difference and | some kinds of equipment will still run fine, it is not always the case - | especially for equipment with motors. (It is my impression that | switching power supplies are extremely tolerant of variations in input | voltage.) | | I've been involved in situations where equipment which was specified | for 220-240V required a "boost transformer" to run properly. There are multiple different 3 phase voltage standards in the US, mostly due to the original decision to do the 110/220 (now 120/240) split phase system. The early one was 240 delta with one side split for 120 volt stuff. Many power companies no longer provide it for various reasons (one is that they are moving to using wye primary and wye-delta can cause backfeed between phases when one phase is lost). The 208/120 volt wye is now more common for new installs (probably why a boost was required in the situation you had). Then there's 480/277 wye for heavy duty stuff, and the occaisional 600/347 (more common in Canada). Europe has it much simpler with just 400/230 for all but the heavy industrial uses. | P.S. the nominal single phase voltage in the US is 120V (or maybe 115V | - or maybe even 110V :-) It is half of the hot-to-hot voltage | (nominally 240V), and my local power company specifies +/- 5% for | residential use and +/- 10% for other retail. It was 110/220 until around 1940 or so then it went to 115/230 for a while then in the 1950s they went to 120/240. The US was poised to deliver three phase to homes until the Rural Electrification Administration decided to go with single phase for lower costs on those long rural lines. FYI, if you get your power from a decent three phase generator, you can usually adjust the regulator over a rather wide range of voltage, usually 25 to 30 percent or so. If you need 240 volt delta, set the regulator for 240/139 if it's wired for wye and don't try to run anything else on it. -- ----------------------------------------------------------------------------- | Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ | | (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ | ----------------------------------------------------------------------------- ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
