On Apr 27, 9:15 pm, Owen Duffy wrote:
Keith Dysart wrote in news:1177719266.182305.327520
@l77g2000hsb.googlegroups.com:
My recollection is of being introduced to phasors with the study of
electric machines which have real rotating magnetic fields. By
jumping onto the rotor and rotating with those magnetic fields,
solutions became trivial by allowing vector arithmetic on the now
stationary phasors.

Isn't hopping onto the rotor (assuming synchronous speed) to make your
observations called moving from the time domain to the frequency domain,

I am not sure it is that; more like rotating the frame of reference to
stabilize the view (or a stroboscope perhaps?). The time domain is
now captured in the notation on the diagram that says it is all
happening
at 60 Hz, for example.

and all the mathematical shortcuts are only valid if all quantities share
the same angular velocity (or frequency), implying sinusoidal waveform.

But I agree with this. If everything is not rotating with the same
velocity
(and not just frequency), then it is difficult to find a useful frame
of reference
to rotate.

Which suggests that if there are two directions of rotation, phasors
don't help much with the solution.

I guess a departure from the strict phasor environment is for example
when we consider a noise vector rotating about the end of a carrier
phasor in exploring FM detector S/N vs C/N.

....Keith