Total Motor Currents

[Acetronics2]

Hi, Darrel

When adding the current for the 2 motors, you should calculate a VECTORIAL addition ...

but the sum modulus of two vectors is not compulsory equal to the sum of the modulii ... generally, It's lower ...


Your results mean current for both motors have a different de-phasing ( ? ) ,called Cos Phi in Europe, from voltage.

Alain

[sougata]

Hi, Darrel
Your results mean current for both motors have a different de-phasing ( ? ) ,called Cos Phi in Europe, from voltage.
Alain

While that explains the phenomena, you should be busy working up the remedy.

Possibly you would need to sample the voltage as well and find the phase difference between the current and voltage to calculate active/reactive/average power. While zero-cross detection can be used on the current and voltage sampled approach can also work.
Consult AN939 from the mchip website. And here is something that may interest you http://www.circuit-magic.com/acpower.htm