Re: Variac++

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Matthew Smith by way of Terry Fritz <teslalist-at-qwest-dot-net>" <matt-at-kbc-dot-net.au>

Hi Jolyon/Jim/All

Jolyon Vater Cox wrote:
>Does your "power" meter also have another set of terminals connected 
>between phase and neutral (or a derivative of it) to drive the voltage
 > coil?

Jim Lux wrote:
 > You gotta have 3 terminals to measure power...  (are they using
 > chassis ground (tied to neutral) as the third terminal? Stranger
 > schemes have been used)

It's an voltmeter (1Vdc fsd) - identical to the other two which are being 
used on voltage and current.  Current and Power go through "current 
transducers" which convert Iac to Vdc.

Without major disassembly, it seems that the CT which feeds the 'power' 
measurement is on the supply side of the Variac so yes, it looks like 
voltage is assumed.

I will, therefore, treat the scale as "approximate kVA"  (the unit's 
actually rated at the "continental" voltage of 220V whereas the local 
supply is actually 240V).

Thanks for the information.

Cheers

M

-- 
Matthew Smith
IT Consultant - KBC, South Australia
KBC Web Site    http://www.kbc-dot-net.au
PGP Public Key  http://gpg.mss.cx