[time-nuts] Modern motherboard with RS232 port

[Christopher Brown]

IIRC...

VA for AC is peak volts times amps, not RMS volts.  The whole point of
dealing with RMS being that it makes AC and DC equiv for purposes of V *
A = W.

Converting VA to W is same as converting peak V to RMS V.


Though I am a little surprised about residential power being
measured/billed in VA not KW/h in North America.  Pretty sure the US is
in North America, even Alaska in slightly more North America.  Never
seen a VA/h meter in the US.

Was guessing it was a CA thing, even though I had never run across any
mention of VA billing in CA, but am looking at Manitoba Hydro, NB power
and SaskPower billing rates right now in KW/h.

Ed, can you chime in here, where is power billed by VA (outside of some
commercial/industrial and private generation agreements)?

VA is used all over the place in electrical systems calculations and
equipment specs but have never seen billing on it.

On 8/19/12 11:19 AM, Tom Knox wrote:
> 
> Hi Ed;
> I may not have had enough coffee yet, but if Volt X Amps = Watts why would there be a difference?
> Best Wishes;
> Thomas Knox
> 
> 
> 
>> Date: Sun, 19 Aug 2012 12:35:51 -0600
>> From: ed_palmer at sasktel.net
>> To: time-nuts at febo.com
>> Subject: Re: [time-nuts] Modern motherboard with RS232 port
>>
>> It's important to remember that on a computer, the wattage shown has no 
>> relationship to the wattage pulled from the socket.  The numbers shown 
>> are maximum values.  You have to measure the power draw and you have to 
>> measure it in volt-amps, not watts because that's how residential power 
>> is measured (at least in North America).  Buy an energy meter that shows 
>> volt-amps.  They're relatively cheap - typically less than $50.
>>
>> Ed
>>
>> On 8/19/2012 11:06 AM, Chris Albertson wrote:
>>> This sounds like a newer version of the board I use.   The thing to check
>>> is if the CPU heat sink has a fan or not.  Having no fan indicates that the
>>> CPU is not using much power.  It also removes a common failure point.
>>>
>>> To reduce power even more.  On an NTP server you can unplug the keyboard,
>>> mouse and monitor and if you have other servers on the LAN configure one as
>>> a "boot server" and have it run TFTP then your NTP server does not need a
>>> disk drive.  It can run off a "RAM disk".  This makes it very fast, even
>>> faster than a SSD and it saves some cash.  Makes backup easy too as there
>>> is nothing to backup if there is no local storage.  If you don't have a
>>> TFTP server use a small notebook size disk drive. Even a 80GB drive is
>>> overkill.  You can also boot from a USB thumb drive and run a RAM disk.
>>>
>>> It is worth it to look at your electric bill to find how much you pay for
>>> power.  Here I'm at $0.21 per KWH.  A full size PC server can use 250W or
>>> more.  There are 8760 hours in a year so you get $460 per year to run that
>>> 250W PC.  The little Atom will pay for itself in just a few months.  The
>>> first time I did that calculation, my "power hogs" where given away.
>>>
>>>
>>>
>>>
>>> On Sun, Aug 19, 2012 at 7:42 AM, Stan, W1LE <stanw1le at verizon.net> wrote:
>>>
>>>> Hello The Net,
>>>>
>>>> For your consideration:
>>>>
>>>> The INTEL model DN2800mt ITX mother board uses a ATOM CPU and
>>>> draws about 11 watts of AC power when configured as:
>>>> (I have not measured DC power yet.)
>>>>
>>>> 30 GB OCZ Nocti mSATA solid state drive,
>>>> WIN7 pro, 64 bit, USB keyboard and mouse
>>>> APEX MI-0008 case.
>>>>
>>>> Also has:
>>>> parallel port available on mother board, you extend to a connector
>>>> RS232 serial port available on mother board, you extend to a connector
>>>> a single DC power supply from 11 to 19 V DC.
>>>> 1 each PCIe expansion port, I will use with a premium 4 channel sound card
>>>> SATA ports available for HDD/SDD,
>>>> USB ports are available,
>>>> Motherboard sound, and Gigalan.
>>>>
>>>> I have not played with NTP, (yet), but it sounds like a decent time nut
>>>> technical challenge.
>>>>
>>>> My application is for a remote site with only 13V DC power available from
>>>> PV/batteries.
>>>> Then use fiber ethernet to get off site.
>>>>
>>>> The INTEL website would have further details.
>>>>
>>>> Stan, W1LE    Cape Cod   FN41sr
>>>>
>>>>
>>>>
>>>>
>>>> ZZZZz
>>
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