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Bobr:
Even if your theory is right for power supplies there are many other electronic circuits that can suffer.
Computer monitors show thin lines, speakers hum, Cisco routers and equip. are not recommended to be used with modified sine wave, etc., etc.
Why scrimp on spending a $100 or $200 more just to have the best and be done with it ?
John
On Thu, 20 Nov 2003 13:01:10 -0800 , "bobr" <bobrabcd@xxxxxxxxxxxxx> wrote:
>In the old days there were linear and switching power supplies in
>computers. The linear types did not like the pulse width modulated or
>modified sinewaves, but the switching supplies that replaced them and as
>are used today, actually run more efficiently with the modified sinewaves.
>The linear supplies input transformers and fans would overheat, but the
>switching supplies run cool, are lighter weight and have dc fans and
>consume less power.
>
>
>
>
>> [Original Message]
>> From: John Blucar <blucar@xxxxxxxxxxxxxxxx>
>> To: <bobrabcd@xxxxxxxxxxxxx>
>> Date: 11/20/2003 12:50:43 PM
>> Subject: RE: Mark's massive elec. backup system
>>
>> I'm looking again for that link on the web where an engineer told how he
>used to build big UPS's for a company and that modified sine wave was
>garbage and that it went square under heavy loads and DID mess with
>computer power supplies not to mention the problem of harmonics from not
>true sine waves.
>>
>> I'll post it when I find it.
>>
>>
>> John
>>
>>
>> On Thu, 20 Nov 2003 11:43:09 -0800 , "bobr" <bobrabcd@xxxxxxxxxxxxx> wrote:
>> >no no, Mark may have it figured right. Switching power supplies in today's
>> >computers don't have input transformers and actually prefer the root mean
>> >square of the modified sinewave. Even the fans run off of DC so that isn't
>> >a problem.
>> >
>> >
>> >> [Original Message]
>> >> From: John Blucar <blucar@xxxxxxxxxxxxxxxx>
>> >> To: <omega-list@xxxxxxxxxx>
>> >> Date: 11/20/2003 11:20:34 AM
>> >> Subject: Mark's massive elec. backup system
>> >>
>> >> OK, ok. Here's my "contribution".
>> >>
>> >> There very well may be a crucial flaw in Mark's massive elec. backup
>> >system (opinion of Tripplite technician).
>> >>
>> >> Always having admired Mark's massive elec. backup system for his
>> >computers (images on his website), I started investigating the same for my
>> >own use.
>> >>
>> >> (Of course all we have to go on with his system is what we see in the
>> >images and the descriptions.)
>> >>
>> >> What I discovered: Apparently he is using a TrippLite inverter connected
>> >to a surge strip to power his system(s) 24/7/365. He has a massive bank of
>> >batteries to supply the inverter in case of power outage.
>> >>
>> >> I called and asked a Tripplite tech to take a look at the system on the
>> >web (a second level up tech). His comments ? Beyond the electronic rocket
>> >science stuff he started with that I did not understand, he said that
>> >Mark's system is essentially different than your standard UPS system.
>> >>
>> >> This is because a standard UPS system supplies perfect sinewave 120 v
>> >power most all the time taking the power from the uitility company, and
>> >only rarely does the UPS kick in with batteries to provide modified sine
>> >wave power for short periods.
>> >>
>> >> On the other hand, as the images show Mark's system pulls modified sine
>> >wave power from the inverter 24/7/365. According to the tech, he said that
>> >it's iffy at best, that you have to consult the power supply manufacturers
>> >in your computers to be certain they approve. It's because even modified
>> >sine wave starts breaking down under heavier loads (like during an extended
>> >power outage), and then it becomes more like square wave, which can cook
>> >your computer power supply transformers, etc. Even if not loaded hard,
>> >modified sine wave still produces some pretty nasty harmonics that can mess
>> >with your electronics.
>> >>
>> >> The safer solution ? For a few dollars more you buy the Tripplite Smart
>> >Online SU series which produce a 24/7/365 perfect sine wave whether on
>> >battery power or on 120 volt utility co. power. Then you just add an
>> >external battery source as those do allow that. (This is what I just
>> >bought).
>> >>
>> >> http://www.tripplite.com/products/product.cfm?productID=2664
>> >>
>> >> They come in larger sizes if you need 'em.
>> >>
>> >> Anyway, that's my 2 cents.
>> >>
>> >>
>> >> John
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