UPS for FreeBSD

[Michael Powell]

Darren Pilgrim wrote:

[snip]
>>> 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.

I absolutely agree. I have a large line conditioner I pulled from a mini-
frame that was being decommissioned and scrapped. It filters line noise, 
spikes, transients, high-freq noise, etc, and contains a constant voltage 
transformer that can even buck up short line voltage sags. There is no such 
advantage to having/using such a beast only to place a non pure-sine wave 
UPS between it and the computers. Defeats the purpose of having it in the 
first place as such units will only reintroduce all the crap the line 
conditioner cleans up. 

Of course, the obvious idea would be to put the UPS in front of the line 
conditioner, but that's also a no-go for various other reasons.

Was just bringing this up to say: spend the extra money and get something 
good. My main background early in life was analog electronics and RF, before 
I got into computers. I've been looking around for something inexpensive for 
home use, but my show-stopper spec is I won't use anything that isn't pure 
sine wave. And that translates to $$$. Haven't found anything yet that is 
inexpensive and satisfies my requirements.

-Mike