From owner-freebsd-questions@FreeBSD.ORG  Thu Oct 17 05:23:20 2013
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
Delivered-To: freebsd-questions@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115])
 (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTP id D5EFC660
 for <freebsd-questions@freebsd.org>; Thu, 17 Oct 2013 05:23:20 +0000 (UTC)
 (envelope-from wblock@wonkity.com)
Received: from wonkity.com (wonkity.com [67.158.26.137])
 (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by mx1.freebsd.org (Postfix) with ESMTPS id 8D26B2248
 for <freebsd-questions@freebsd.org>; Thu, 17 Oct 2013 05:23:20 +0000 (UTC)
Received: from wonkity.com (localhost [127.0.0.1])
 by wonkity.com (8.14.7/8.14.7) with ESMTP id r9H5NCpL014127;
 Wed, 16 Oct 2013 23:23:12 -0600 (MDT)
 (envelope-from wblock@wonkity.com)
Received: from localhost (wblock@localhost)
 by wonkity.com (8.14.7/8.14.7/Submit) with ESMTP id r9H5NCJl014124;
 Wed, 16 Oct 2013 23:23:12 -0600 (MDT)
 (envelope-from wblock@wonkity.com)
Date: Wed, 16 Oct 2013 23:23:12 -0600 (MDT)
From: Warren Block <wblock@wonkity.com>
To: Erich Dollansky <erich@alogt.com>
Subject: Re: UPS buying suggestion
In-Reply-To: <20131017093820.6a8428de@X220.ovitrap.com>
Message-ID: <alpine.BSF.2.00.1310162309200.14022@wonkity.com>
References: <CACo--msUpY-6r7MkuEvrPDpSVdFZyBotSA-eS7aLGMFDeq_vDQ@mail.gmail.com>
 <alpine.BSF.2.00.1310150911510.97788@wonkity.com>
 <CACo--mvUfcAy=0hyun21DZwSmdd=SmP7EeU-FVxJyiT_h4Rxkg@mail.gmail.com>
 <525F0138.1020304@fjl.co.uk>
 <20131017093820.6a8428de@X220.ovitrap.com>
User-Agent: Alpine 2.00 (BSF 1167 2008-08-23)
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.4.3
 (wonkity.com [127.0.0.1]); Wed, 16 Oct 2013 23:23:12 -0600 (MDT)
Cc: Frank Leonhardt <frank2@fjl.co.uk>, freebsd-questions@freebsd.org
X-BeenThere: freebsd-questions@freebsd.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: User questions <freebsd-questions.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-questions>, 
 <mailto:freebsd-questions-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-questions>
List-Post: <mailto:freebsd-questions@freebsd.org>
List-Help: <mailto:freebsd-questions-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
 <mailto:freebsd-questions-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 17 Oct 2013 05:23:20 -0000

On Thu, 17 Oct 2013, Erich Dollansky wrote:

> Hi,
>
> On Wed, 16 Oct 2013 22:12:24 +0100
> Frank Leonhardt <frank2@fjl.co.uk> wrote:
>
>> On 16/10/2013 03:43, yudi v wrote:
>>
>> At the risk of going off-topic: as Warren has pointed out, not all
>> UPS units are the same. In fact, many units calling themselves a UPS
>> are actually backup power supplies, which switch over to battery if
>
> it is a rare event to see the on-line version here. Of course, they are
> much better when it comes to wave form and switch-over time. The wave
> form is very close to a sine wave and they do not have to switch over
> as they are always providing the power.

> But you also must see the cost. You loose about an extra 10% of
> electricity in the system. So, it is also a cost factor.

Online UPSs are rare and expensive everywhere.  Computer power supplies 
are not as sensitive as they once were, and the switchover time of 
standby UPSs is almost certainly adequate.

About sinewave output: http://www.jkovach.net/projects/powerquality/ 
shows oscilloscope screens for an APC Back-UPS, Smart-UPS, and line 
voltage, and talks about the differences.  Amusingly, the Smart-UPS 
provides a cleaner sine wave than comes out of the wall.