What is the Difference Between ( KWHM & KVARHM )

A1: the cosine of the phase angle between voltage and current.

A2: yes.

Hi PWSlack

i know the angle must be ( -90 ) between A & V

I notice that the internal instruction is the same for the tow meters

but i want the work theory for each of them 3 ph & 1 ph.

And ask if the var meter must be always delta internal conn. and watt meter star conn.

Thanks

For older electro-mechanical (disc-type) meters, there is no internal difference. An external phase shifting transformer is used to offset the voltage inputs by 90º. Digital meters sample voltage, current and phase angle simultaneously. Once you've got those numbers it's just math in the processor to determine which output to display, and most digital meters can display either parameter with the press of a button.

thank you

verry much