Thanks Max,
It turns out that the over simplified line in the catalog
1000w/1500VA has to do with the company calim of providing that wattage on 
a 1500VA draw.
it is a battery back up. I am glad it's not my project.
Thanks again.


On Tue, 31 Jul 2007, Max Robinson wrote:

> Volts times Amps isn't necessarily watts in AC circuits.  It has to do with
> the phase relationship of the voltage and current.  If they are exactly in
> phase then volts times amps is watts.  But if they are out of phase the
> watts are less than volts times amps.  How much less depends on how far the
> current and voltage are out of phase.  Airconditioners are nearly always
> inductive loads which makes the current and voltage out of phase.  The wire
> size and circuit breaker have to be rated for the volt amps not the watts.
> The horse power of a motor is related to the watts.
>
> Regards.
>
> Max.  K 4 O D S.
>
> Email: [EMAIL PROTECTED]
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> ----- Original Message -----
> From: <[EMAIL PROTECTED]>
> To: <[email protected]>
> Sent: Monday, July 30, 2007 11:16 PM
> Subject: [BlindHandyMan] watts vs VA
>
>
>> Hi,
>> My electrical math is shallow.
>> But I thought, that volt times amp will give you a number equalling the
>> amount of watts that one can pull from a circuit.
>> A standard 117v at 15A is 1750 (1755 to be exact)
>> I thought this came up while we were discussing how a (rounded off) 120v
>> device can't give the HP that some units claim. So you guys figured  that
>> it must be momentary, to start, or burst HP, or hype in some of those
>> claims.
>>
>> So wattage vs VA:
>> In heavy duty power back up for heavy amplifiers one unit quoted
>> 900w/1500VA for 7.5 mins total.
>> But shouldn't the wattage and the VA be the same?
>> If not, wy?
>> We are going overboard, but have been known to lose up to 3 mins in the
>> start up needed by the AC units.
>> It's not our building, the need a new bigger service.
>> So we are just getting back up o\power supply.
>> What's the real math, is this right?
>>
>> Thanks
>>
>>
>>
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