I'm new to 3 phase AC sinusoidal system and my question may sound clueless, I would appreciate your patience.
Say controller(drive) is sending out three phase sine waves and the controller side is delta connected and motor side wye connected. Then my understanding is, the motor side sine wave will be phase-shifted by 30 degrees. Am I correct?
Then my question is, how to make it +30 degrees shifted and how to make it -30 degrees shifted? In other words, is there a way to control the shifted-phase to be ahead(+30) or behind(-30)?
My next question is,
Now let's say phase shift is +30 and now I reverse the motor rotation direction i.e. any two wires out of three wires are switched, what happens to the phase shift?
Does it remain +30 degrees or does it become -30 degrees?
My last question may really sound clueless but...
A 3 phase AC sinusoidal motor driven by 3 phase AC sinusoidal drive will be somewhat similar to stepper motor in that, the 3 phase sine waves will specify a single rotor position(angle) at any given moment and can even stop the rotor at any angle with tremendous zero-speed torque... Then why would a 3 phase AC sinusoidal system need feedback? I.E. Why should it run closed-loop? Why can't it be run open loop without feedback circuit just like a stepper motor? Give enough RMS to the sine wave signal, then the sinusoidal motor will never miss a step (step is not a right word here but I do not know how else to describe it)...
Thank you for your time on this newbie.