# Converting Single Phase Mains into 3 Phases (No VFD) [closed]

I have a goal to build a circuit from scratch to simulate a 3 phase motor. I do not have any specific requirements, rather, I want to make sure that I understand what is wrong with my approach and current understanding. From what I remember in school, a capacitor can be used to induce a phase shift in an AC source, my question therefore follows, how can I design a circuit that shifts phases at intervals of 120 degrees?

The crude drawing below attempts to portray my attempt at understanding this. 3 sets of electromagnets, same size and number of windings, are placed in this configuration and all three are connected to mains, with the addition of three capacitors set at different values to induce the desired phase shifts (We are also assuming all applicable safety circuits and practices, etc). From what I have read, it seems as if this is a gross oversimplification of a practical circuit, if any degree of accuracy can even be located. Please help me understand.

• You are very crudely describing what is called a "static phase converter". It's generally a bad idea. Rotary phase converters using an idler motor are a better one, and VFD's which rectify the single phase input and electronically synthesize 3 phases are a good one. All of these are quite hazardous if you don't know what you are doing. The bigger problem though is that you said you need to "build a circuit from scratch to simulate a 3 phase motor" - "simulating" a motor doesn't make much sense here, you might as well do that with a computational model as with mains voltage. – Chris Stratton Aug 9 '17 at 0:46
• Please read up en.wikipedia.org/wiki/Scott-T_transformer – Janka Aug 9 '17 at 0:52
• consider a motor-generator and how energy is converted and impedance is low. then compare to the impedance of Caps – Tony Stewart Sunnyskyguy EE75 Aug 9 '17 at 0:56
• @ChrisStratton, I poorly worded my intentions, I wanted to understand the practicality/feasibility of this approach, I haven't intended to attach a load to the circuit or conduct any simulations. – Alex Riphin Aug 9 '17 at 20:44