From owner-freebsd-questions@FreeBSD.ORG Sun Nov 30 16:11:47 2014 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id BC77239A for ; Sun, 30 Nov 2014 16:11:47 +0000 (UTC) Received: from nm4.bullet.mail.bf1.yahoo.com (nm4.bullet.mail.bf1.yahoo.com [98.139.212.163]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 70754312 for ; Sun, 30 Nov 2014 16:11:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1417363905; bh=BKMrapQKxknxRD7oT1QjPlHmG3sPLzLpK26SQ0DoQGs=; h=Date:From:To:Subject:References:In-Reply-To:From:Subject; b=juLbrG5ANmrWh3lzW2GvBaikwdjCCPmpzSTH6dFiUCRHVgb+zTaGLAZpo8gfMDAM7wovGX6xnF57ME0lPK+N6O58pRZkdgm5SmcrJViGTUmfCu5XbpcyzSOMPyJl+IFtWT5phhB/R/h6cM60WF0/VevqpNwQYhDcEx5YTNI89NYD9OwgqzxiL2ifiYow8SZ4uoPc2N5xbOSFpuQpyGgX6FxTXXlqjlt4rRXMSSihhodFxO+s7ZVt8PYleKTdRk31KdFrsnjxoenrJiJmAeYfirn9PvcFSBkk67XC2dqBqwseM5sMxlBn7195pgXNfw6S6FyH5k5BVKPVwsuQs5SeXw== DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s2048; d=yahoo.com; b=JCRKXsyOZ/7KWoGOpbNNryXn2OI5FT2qgXLLfyU1fpWEHyeH5Mb8+Dgq9z/ilisV6KLZy0+yxvc4lkHUlZuegqEUZ3OVxFw4DvfTy/AxePzPX+eoG3ljEi+mrFHqF/XuabfgMWaBMyqDFQQwlx7yNRj88AD5gw1bhTrIYBkLWAouHfaG4RF3Lox/+eZq1Xqsv2uD2PPAbAYan2t+DOYchcIxFoM9ddbV5ZKOqwvHNCg3a93mexkcbHj6hW+BJ3zIG3g2dCEL3Hk8LOwFyAcOD+HOwnhsRqOa9yKExF9+mcmuBSTpbNkNl4sSVoQXAa3Db0CzGLr2dcnvGuirfJo8pw==; Received: from [98.139.212.153] by nm4.bullet.mail.bf1.yahoo.com with NNFMP; 30 Nov 2014 16:11:45 -0000 Received: from [98.139.211.161] by tm10.bullet.mail.bf1.yahoo.com with NNFMP; 30 Nov 2014 16:11:45 -0000 Received: from [127.0.0.1] by smtp218.mail.bf1.yahoo.com with NNFMP; 30 Nov 2014 16:11:45 -0000 X-Yahoo-Newman-Id: 551636.83217.bm@smtp218.mail.bf1.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: Gq7vVzQVM1moYIHKSwXkLSvEwQhVt_c.IQ3vBe5Hp804UFE MGOcX.rv1iAVvO7yJZBLVmon.TtTi4m3KH.C8W0AEwLn7vImCd3qSpGFTZkI 2mKOYvn9tMOvX._U3MZJocyP0sPQKZLXGkZLhsavZoS2GGPuTXV0JvOqMtAN PGsOWstYIyqgm6_O9bjBX.EzkD4oOHHa18izN0DhM8hgzTSfKfQlJ11TvnOR IQc6DLTkEDTdq4hufE1AMtxAh9yxfzNBZjB4DqAh9tNVt5c9yhy23rV70E2n E2gylW0mMASCMw1Ov7.9sqY0RhhiEx_qgOJ7z_2mYEHulXt_Atcu.w2HdvUW 37zi32.WetiRSOf.EF6PhbD1km6ZCbuCqtwUvKb_Zxjghr3rUWRpv5d7QOpE AlvTPxIYMgz1wkchroR6uA3y.synJpX41wD2Pe2l7W1i0yELNqjlQP6g3ckZ m8tXrqIqT8qUQg3aTp4meW4QreYxf6d__qCUi1UYx4JpOQHJX9hxie2.LQiJ cEqiKFgVT5znqwi_Vqow.nUS9159zRhhUqkfE7dzqd1ZJo_BBURdF.Aefmhv OAV1HYJZGFBMTfEzEiixXrDnj0mIcu6vpxkcQ08Jxkje4gxXjdhoeVH1NZ1y mk7.oPCRI4bzZ1awuQ6ng X-Yahoo-SMTP: h3Xqg6.swBC0yI913RMMwp94grO_cg-- Message-ID: <547B41BE.20700@yahoo.com> Date: Sun, 30 Nov 2014 11:11:42 -0500 From: Paul Pathiakis User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: John Johnstone , freebsd-questions@freebsd.org Subject: Re: UPS for FreeBSD References: <54777AB1.9010800@bluerosetech.com> <54779629.302@bluerosetech.com> <54789AF3.7090100@yahoo.com> <547AAC20.1050006@tridentusa.com> In-Reply-To: <547AAC20.1050006@tridentusa.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 30 Nov 2014 16:11:47 -0000 To all that responded on this thread: Thank you. I feel I have a better understanding of all this now. :-) The time spent to better educate others and myself is welcome and so "FreeBSD Community". P. On 11/30/2014 00:33, John Johnstone wrote: > I agree this thread is extremely long so I'll consolidate. > > On 11/28/14 10:55 AM, Paul Pathiakis via freebsd-questions wrote: >> Again, these UPSes are not double sine wave, they are stepped. You can >> get one for cheap, but, again, how much value do you place on your >> server and the information it has? If you're looking at APC, you have >> to look at their 'server class' UPS. They start (I think) at 1500VA and >> about $850. > > I think things could be clearer about the terms "double sine wave" and > "stepped". I think it should be made clear that although a UPS that > outputs a 60 Hz square wave is producing a poor approximation of a > sine wave, better designs still produce a sine wave in a stepped > fashion, just with a higher number of steps. One that produces an > infinite number of steps would be indistinguishable from a pure sine > wave. > > On 11/28/14 5:04 PM, Paul Pathiakis via freebsd-questions wrote: >> I found this which seems to be pretty solid. I believe it someone >> mentioned UltraUPS. >> >> http://www.controlledpwr.com/whitepapers/uutopla1.pdf > > This whitepaper refers to the stepped approximation of a pure sine > wave in their design: > > "The inverter reconstructs a sinewave from the DC using PWM (pulse width > modulation); a method that “digitizes” the DC into various width pulses > to make an AC sinewave." > > The number of steps needs to be high enough to not cause problems. > > On 11/27/14 2:25 PM, Darren Pilgrim wrote: >> Sine-wave approximating inverters do bad things to any power supply >> with a regulator cap (which is everything that won't catch fire on >> its own). The issue is the high frequency components and the >> hundreds of under- and over-voltage events per second inherent to the >> stepped square waveforms used (every step is a spike or sag). >> >> UPS manufactures know this is bad, so they try to hide it by calling >> it "modified sine wave", "quasi sine wave", "simulated sine wave", >> "PWM sinewave", etc., and hope you're dumb enough to fall for it. I >> have yet to see a consumer UPS that doesn't do this. > > I wouldn't say it fair to interpret UPS manufacturer's descriptions of > their methods of simulation as "hiding". > >> You need to buy a server-grade UPS to get something that won't damage >> your electronics. APC SmartUPS, Cyberpower PFC Sinewave or Smart >> App, Eaton 5P/PX or 9 series, Tripp Lite SmartOnline, etc. > > On 11/28/14 1:22 PM, Paul Pathiakis via freebsd-questions wrote: >> "Simulates" utility power. This is the sneaky little bit of >> marketing. Saying it's sine output.... It is, but it's simulated. >> I've been roped in by the APC marketing machine previously. > > As far as "simulated" being a bad thing, by definition all UPS's have > to simulate a sine wave once the AC power goes away. It is just a > question of how close an approximation is it. There's no question > that a 60 Hz square wave would be a poor approximation. > > As the number of steps increases, the magnitude of the "high frequency > components" and "under- and over-voltage events" becomes so small as > to be negligible. There are plenty of "server-grade" UPS's that > produce a step approximated simulated sine wave as the Controlled > Power whitepaper states. > > One aspect to consider is that if a UPS isn't an on-line design, any > negative effects experienced by the load due to the quality of the > output sine wave will only occur when the output is being produced by > the UPS during a power failure. It's reasonable to expect that this > is going to be a short interval which in many cases may not cause any > power supply problems. > > - > John J. > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to > "freebsd-questions-unsubscribe@freebsd.org"