From owner-freebsd-isp Sat Nov 15 12:34:21 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id MAA20093 for isp-outgoing; Sat, 15 Nov 1997 12:34:21 -0800 (PST) (envelope-from owner-freebsd-isp) Received: from smtp2.teleport.com (ns0.teleport.com [192.108.254.11]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id MAA20060 for ; Sat, 15 Nov 1997 12:34:12 -0800 (PST) (envelope-from mrl@teleport.com) Received: from user2.teleport.com (user2.teleport.com [192.108.254.12]) by smtp2.teleport.com (8.8.7/8.7.3) with ESMTP id MAA06609; Sat, 15 Nov 1997 12:34:06 -0800 (PST) From: Mostyn/Annabella Received: (from mrl@localhost) by user2.teleport.com (8.8.7/8.8.4) id MAA24040; Sat, 15 Nov 1997 12:34:05 -0800 (PST) Message-Id: <199711152034.MAA24040@user2.teleport.com> Subject: Re: Power To: dev@wopr.inetu.net (Dev Chanchani) Date: Sat, 15 Nov 1997 12:34:04 -0800 (PST) Cc: freebsd-isp@FreeBSD.ORG In-Reply-To: from "Dev Chanchani" at Nov 15, 97 01:13:36 pm X-Mailer: ELM [version 2.4 PL25] Content-Type: text Sender: owner-freebsd-isp@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > We had an extended power outage last night. After realizing that our UPS's > would not keep our network up for the black-out, I ran to sears with a > credit card and bought a Craftsman generator. > > My lesson in power began :) > > I was wondering if anyone has been through this and could help me on a > couple of points: > > We have our servers, switches and routers plugged into APS UPS's (600's > and 650's). The UPS's are plugged into surge protectors. The surge > protectors are plugged into 15 AMP 12 guage 100 ft extension coards. We > ran the extension cords (took them out of the wall) and plugged them into > the generator. The 650 UPS could not take it, it was flipping between > generator power and UPS power every second. So... my questions are as > follows: > > 1. Can you plug a UPS -> Surge protector -> generator I thought about doing similar - Here are some replies from UPS makers: 1. Tripplite MHS: Source date is: 14-Oct-97 11:04:09 -0500 CDT None of our units were made to run on line with generators. The reason is because most generators do not put out a pure sine wave or do not have the hertz controlled at 60. What we have come across is that when there is a power outage and the generator "kicks in" our units will still stay in battery. The reason is because our units need to see good power going into them in order to come off of battery power. 2. Liebert I would not recommend using the POwerSure Interactive on the Coleman 5000, as the PowerSure Interactive will switch to battery each and every time the frequency goes out of range, as well as when the voltage does. This would in affect have the PowerSure Interactive switching to batteries every few minutes. The optimum solution would be to have an online UPS as with an online UPS, the UPS will not switch to battery for frequency deviations. Specifically with the Coleman 5000, I would recommend not to use anything larger than the UPStation GXT 1500 which is an online UPS. As a general rule, Liebert recommends sizing a generator application at a 3:1 ratio. (Size the kW of the generator 3x the size of the UPS). The main reason that Liebert recommends an online UPS is that when the frequency deviates, an online UPS will "free-run" utilizing its own oscillator to generate the frequency. A line interactive or off line UPS must transfer to battery. If you have any further questions, feel free to contact me. 3. APCC Although I am not familiar with the Coleman generator specifically, here are some guidelines that we recommend when selecting a UPS / generator combo: - Use a Smart-UPS, which can be desensitized to allow the slightly less than perfect generator power to pass through. If this is not done, the UPS will detect a less than perfect sine waveshape and will stay on battery. - Use a computer grade, pure sine wave output generator. - Make sure that the generator is oversized by at least 4 times the load which you will be placing on it. In your case, the 5000 watt generator should have a load of no more than 1250 watts placed on it. Mostyn Lewis