Are single phase motors with capacitors always wound 90 degrees out of phase?

Factual Questions
1

Many single phase motors have two windings that are mechanically out of phase with one another, and one of the windings is driven through a capacitor so that they are electrically out of phase. Independently, there can be a run capacitor that is always in the circuit, and/or a larger start capacitor that is kept in the circuit at low speeds through a centrifugal switch. Generally, the capacitor(s) causes a phase shift of less than 90 degrees, but enough so that the motor can start itself rotating.

My question: is the mechanical phase shift between the windings always 90 degrees? Or are they ever wound with a less than 90 degree shift?

If it is obscure what I am asking, consider a shaded pole motor, in which the shading winding or shorting coil is built into the stator in such a way that it is somewhat out of phase with the rest of the stator but nowhere near 90 degrees. Or, consider this thought experiment with a PSC motor: suppose there is a little residual magnetism in the rotor, and spin it, with no capacitors. Would an oscilloscope looking at X versus Y on the two poles show a circle or an ellipse?

2

Not sure what you are getting at in the second question.

The first one, yes it is usual practice to have a start-up winding 90 degrees from the main winding. I guess its possible to have a reduced angle of phase winding but there does’t seem any point, and if you had a heavy rotor there is a theoretical possibility that you just would not develop enough rotation to ensure that it was in a position to be further turned by the reversing field on the next a.c cycle.

You can build a motor that is separately excited using a couple of slip rings and a d.c supply derived from a rectifier, and there is a specific use for such a motor as it can either be speed controlled or develop a lot of start-up torque, and can be used in certain power factor correction applications.