Abstract A squirrel-cage motor of the ferroresonant type, having two pairs of stator windings in series with respective tuning condensers energized in parallel from a source of alternating current, is provided with a feedback winding on each stator pole designed to aid or to oppose an applied control signal, all the feedback windings being connected in series across two branches of a phase-discriminating network extending from a common terminal to symmetrical taps on two parallel stator windings. Each branch includes a resistor in series with a diode, the two diodes being oppositely poled so that a voltage difference is generated across the feedback circuit upon a relative phase shift of the currents traversing the two pairs of stator windings. The common terminal is energized by an AC voltage in step with the supply voltage through a transformer or a resistive voltage divider.
A servomotor comprising a stator with a plurality of poles arrayed about an axis, a short-circuited rotor centered on said axis, a source of alternating driving current for said stator, first and second winding means on respective poles in series with respective tuning condensers connected in parallel across said source, a phase-discriminating network having two branches connected between a common terminal and a pair of symmetrical taps on said first and second winding means, and a feedback circuit including respective coils on said poles serially connected across said branches for energization in response to a relative phase shift in the currents traversing said first and second winding means, said coils being connected in mutually inverted relationship with said first and second winding means.
Claim 2
Dependent Claim
123 words
A servomotor comprising a stator with a plurality of poles arrayed about an axis, a short-circuited rotor centered on said axis, a source of alternating driving current for said stator, first and second winding means on respective poles in series with respective tuning condensers connected in parallel across said source, a phase-discriminating network having two branches connected between a common terminal and a pair of symmetrical taps on said first and second winding means, and a feedback circuit including respective coils on said poles serially connected across said branches for energization in response to a relative phase shift in the currents traversing said first and second winding means, said coils being connected in mutually inverted relationship with said first and second winding means.
Claim 3
Dependent Claim
40 words
A servomotor as defined in claim 1 wherein each of said branches comprises a resistor and a diode in series, said diodes being oppositely poled, said feedback circuit being connected between respective junctions of said diodes with the associated resistors.
Claim 4
Dependent Claim
23 words
A servomotor as defined in claim 2 wherein said common terminal is coupled to said source for energization at the operating frequency thereof.
Claim 5
Dependent Claim
37 words
A servomotor as defined in claim 1 wherein each of said poles is further provided with an auxiliary winding for the application of a control signal in mutually inverted relationship with said first and second winding means.
Claim 6
Dependent Claim
33 words
A servomotor as defined in claim 1 wherein each of said poles is further provided with a biasing winding for energization by a magnetizing current enabling periodic saturation thereof by said driving current.