[ale] OT need 600-1000W power protection for 3 minutes - cheap

Wed Jul 10 16:51:59 EDT 2013

Hi Scott,

I don't think Alex would mind me throwing my 2 cents in.  I'm roaming around right now, but, once I get home, I'll spend a few minutes trying to describe these power ratings.  For the moment, realize that there are two ratings on these ups's.  The VA or volt-ampere rating is the one they rave on about, since it's a bigger number.  However, the rating in watts, which you sometimes have to look for, is a lower number and it's usually your limiting factor.

For example, I have the APC SMT-750 unit.  It will provide 750 VA or 500 W.  The 500 W is my limiting factor, since I'm trying to run about 540 W and it doesn't like it.

The Kill-A-Watt is very handy for seeing what you're actually consuming.  I'd get the Kill-A-Watt EZ, which is a bit more modern and has some cool features the old ones don't.  Home Depot has them.

The UPS I have is a very nice unit, and is less than a year old.  I'm willing to sell it for 25% less than market value.  I think Amazon wants $ 272 for this unit.  So, I'd sell mine for $ 200 with free delivery within 30 miles of GA 400, exit 16, Cumming, GA.  The only problem I have with the unit is that I need more capacity.

Here are some UPS sizing tools which might be useful.  I haven't tried them, I just googled them.

http://www.apc.com/tools/ups_selector/
http://www.apc.com/tools/ups_selector/pso/rslr/index.cfm?ISOCountryCode=US
http://www.tripplite.com/en/lp/application/ups-sizing.cfm

Sincerely,

Ron

Scott Plante <splante at insightsys.com> wrote:

>Wow, the third paragraph on mostly went right over my head. I realize
>you were responding to a post, but is that esoteric background or do I
>need to wrap my head around it to decide what size UPS I need.
>Coincidentally, we also need a new UPS and we're trying to figure out
>exactly what we need. I don't have a Kill-A-Watt, but I see I can pick
>one up for ~$20 if it'll help. The blurb on it claims: 
>
>    * Large LCD display shows kW, volts, amps, watts, Hz and volt amps 
>
>
>
>So how would I use that device, or another method, to size the correct
>UPS? And do I need to perform a calculation involving PI? 
>
>
>Scott 
>----- Original Message -----
>
>From: "Alex Carver" <agcarver+ale at acarver.net> 
>To: ale at ale.org 
>Sent: Tuesday, July 9, 2013 12:45:45 PM 
>Subject: Re: [ale] OT need 600-1000W power protection for 3 minutes -
>cheap 
>
>I have three APC SmartUPS and have no problem whatsoever with apcupsd 
>finding them. I get emails when the system goes on battery and the auto
>
>shutdown works fine across multiple machines with apcupsd sending data 
>to other machines hanging off the same UPS running apcupsd in ethernet 
>mode (no direct data connection to the UPS.) 
>
>Here's your BR/BX explanation: http://forums.apc.com/message/23515 
>The difference between the SMT and the BR/BX is the Smart Slot where
>you 
>can add Smart Slot accessories like various management cards (ethernet)
>
>with temperature sensors, etc. Both the SMT and BR/BX have the normal 
>USB/serial data port for connecting to a single computer. The Smart 
>Slot just allows for direct ethernet connection and management by SNMP 
>and APC's PowerChute software. 
>
>Measuring in VA instead of W isn't marketing rubbish (entirely), it's 
>proper engineering specification for AC circuits. Unless your voltage 
>and current are exactly in phase at all times with no distortions at 
>all, Watts are meaningless unless you also specify VAr or the power 
>factor. Volt-Amps eliminates the need for the power factor because it 
>represents the scalar length of the power phasor (vector) regardless of
>
>where it's pointing in W/VAr space (the 2pi radian range of phase
>angle.) 
>
>Using volt-amps for the specification means that a power supply (the
>UPS 
>in this case) can supply varying types of loads with different power 
>factors and the total available apparent power (real and 
>reactive/imaginary) is constant. A 100 VA motor and a 100 VA light bulb
>
>require the same amount of apparent power. The light bulb needs mostly 
>real power and the motor needs mostly reactive power. 
>
>Where the marketing comes in is the fact that the engineers are forced 
>(by marketing drones) to pick an average power factor so they can label
>
>the object. Typical switching supplies (prior to a concerted push 
>against manufacturers by power companies to make them electrically 
>cleaner) have a power factor of 0.6-0.8 and some really crappy Chinese 
>knock-offs have power factors down near 0.4 with hideous harmonics. APC
>
>assumes a power factor of somewhere around 0.65 for connected devices 
>which is why your Watt rating is lower because some of the available VA
>
>must be used for the VAr portion of the load demand. 
>
>On 7/9/2013 08:45, Ron Frazier (ALE) wrote: 
>
>
>> Hi all, 
>> 
>> To be honest, I need to save some money for this project, since, when
>
>> spending $ 200 at a time, and multiple times, it adds up. But, I hope
>
>> to implement it soon. I might be able to buy one new unit, and reduce
>
>> the load on one pc to use my old ups with that. Not sure yet. 
>> 
>> The more I think about my loads, the more I think I need a 1500 VA /
>~ 
>> 900W unit. A 1200VA/~700W unit might do it, but most product lines
>seem 
>> to jump to 1500 VA after 1000 VA. 
>> 
>> The last time I bought a UPS, it was from Frys. I have no complaints,
>
>> but you do pay sales tax and probably an intrinsically higher price.
>The 
>> advantage is easier returns if needed. I can't believe it, but I am 
>> actually considering mail ordering a UPS. I understand from Amazon 
>> reviews on some, that you have to pay to ship it back to the factory
>if 
>> there is a problem, which can be expensive. 
>> 
>> Based on prior discussions and my experience, I know APC is a good 
>> brand. I also understand that, for the "smart" units, it can be hard
>to 
>> get linux to talk to it, if you want to use the auto shutdown
>software 
>> like apcupsd. I think you guys told me before that Tripplite is good,
>
>> so I may look at those. Based on some amazon reviews and prior
>comments 
>> here, it sounds like I should stay away from Cyberpower. 
>> 
>> I think it's total marketing rubbish that they rate these things by
>VA 
>> primarily. My computer is currently pulling 539 VA and 532 W,
>according 
>> to the Kill-A-Watt EZ, with a power factor of .98. The UPS I have is
>an 
>> SMT-750 so you would think it could handle the load. But NO, that's
>750 
>> VA. The watts are limited to 500, so the thing yells like crazy if I 
>> run this load on it. (So I don't.) So, it should be labeled SMT-500! 
>> That unit was capable of handling the load before I upped the load.
>Yes, 
>> I do know what VA means. It's just difficult to remember to cut 
>> whatever number I see on the box almost in half to get a realistic
>load. 
>> 
>> Charles, thanks for the links. I'll keep the buy batteries local idea
>
>> in mind. Might not be necessary with Amazon's free shipping. 
>> 
>> It's nice to see that the major makers are starting to come out with 
>> some bigger units, with some smarts, with more reasonable price tags.
>
>> 
>> That Fry's link you posted is actually quite interesting. I found
>it's 
>> bigger brother on Amazon. 
>> 
>>
>http://www.amazon.com/APC-BR1500G-BACK-UPS-10-Outlet-1500VA/dp/B003Y24DEU/ref=sr_1_1?s=electronics&ie=UTF8&qid=1373381258&sr=1-1&keywords=br1500g
>
>> 
>> 
>> APC's different model numbers are confusing. For example, I don't
>know 
>> the difference between a BR and a BX unit. 
>> 
>> This unit is a 1500 VA / 865 W unit, with lcd (or led or something) 
>> status display, and AVR (automatic voltage regulation [very cool]);
>for 
>> $ 179 with free shipping and no sales tax. This unit has a BR part
>number. 
>> 
>> This is at a price point / capacity point that's really starting to
>get 
>> my attention. 
>> 
>> Here's a similar unit at Frys. 
>> 
>> http://www.frys.com/product/5955004?site=sr:SEARCH:MAIN_RSLT_PG 
>> 
>> It has a BX part number. Go figure. The capacity is the same, but
>it's 
>> $ 210, or $ 225 after sales tax. 
>> 
>> In any case, much better than the $ 500 Frys wants for the SMT-1500.
>So, 
>> I guess the big question is, what do I give up by going with the
>BR/BG 
>> 1500 and saving $ 300 versus the SMT-1500? I'll have to do some 
>> research on that. 
>> 
>> Alex, good point about the cooling. If I'm using a stock battery and
>a 
>> name brand, it will probably be ok. If I'm using a non standard 
>> battery, that may be something I have to look at. 
>> 
>
>
>
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--

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(PS - If you email me and don't get a quick response, you might want to
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Ron Frazier
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