Date: Thu, 27 Nov 2014 11:25:37 -0800 From: Darren Pilgrim <list_freebsd@bluerosetech.com> To: nightrecon@hotmail.com, freebsd-questions@freebsd.org Subject: Re: UPS for FreeBSD Message-ID: <54777AB1.9010800@bluerosetech.com> In-Reply-To: <m57qdq$did$1@ger.gmane.org> References: <CAHieY7QGp2ELF-R91eu=vSrPsimVmVNJQ4kfucQ56PR7EEZmig@mail.gmail.com> <m57qdq$did$1@ger.gmane.org>
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On 11/27/2014 10:27 AM, Michael Powell wrote: > Alejandro Imass wrote: >> >> I'm looking to buy a UPS for a server I have at home that will work with >> FreeBSD and can signal for server via USB to gracefully shutdown when >> power goes out. >> >> Do any of these work with FreeBSD via USB? >> >> - CyberPower Standby CP425SLG UPS >> - CyberPower Standby CP550SLG UPS >> - Tripp Lite ECO Series 350VA UPS >> - Tripp Lite ECO Series 550VA UPS >> >> Or any other off-the-shelf inexpensive UPS that I can buy at Staples or >> Best Buy that will work with FreeBSD via USB to shut down the server >> gracefully. > > Been looking at the CyberPower ones myself lately. If this is for a desktop > type box with an active PFC power supply go pure sine-wave. The higher the > efficiency rating of the power supply the more touchy they are wrt the non > pure sine wave variety. Almost all modern desktop power supplies today are > active PFC, so the pure sine-wave is becoming a 'must-have'. 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. 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.
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