Angle of load impedance

[electronicsman]

The power per phase is defined as

where

i don't understand the term Theta. I know the phase angle between the
voltage and current if there is reactance they are not in phase .
What does the below statement mean?

 

[BradtheRad]

Does this have to do with power factor error? Due to reactance effects, voltage waveform does not coincide with Ampere waveform.

Impedance waveform does not coincide with either of the two. Evidently the author sees the three waveforms are all out of phase. So he clarifies his expression.

Theta often designates angle. In this case it's the amount by which sine (or cosine) waveforms are out of phase.

 

[electronicsman]

So for example the voltage and current are out of phase by 30Degrees.

and the voltage leads the current by 30. From calculations the impedance leads by 30 Degrees. The author is referring to the +30 Degrees of impedance wrt voltage phase?

 

[FvM]

I don't give a damn for unknown citations...
For a serious discussion, give the source and context.

For me, the quoted statement doesn't make sense. You know that Z=V/I, each being a complex quantity. Respectively the angle of Z is the angle between V and I. If V is leading I by 30 degree (inductive load), Z has an angle of +30 degree.

 

[KlausST]

Hi,

when I first read the post my idea was exactly like FvM´s.
Without context the statement makes no sense. .. and it makes any further discussion almost useless guessing.

Klaus

 

[Easy peasy]

the little "phi" means per phase, or of that phase, for a resistive load the angle, theta, between V & I is zero, giving unity power factor.

for a capacitor only, the current leads the volts by 90 deg, for an L the current lags the Volts by 90 deg - if the C or L has appreciable R in the ckt then the angle is in between these values, e.g. lots of R and very little L = slightly lagging current, say 5 deg behind the volts, etc ...

--- Updated Oct 31, 2020 ---

p.s. the piece of text you are querying is clearly wrong - possibly a typo ...