Multi-element induction device having common armature and power-factor adjusters

Claim 2

In an induction device responsive to a function of the voltamperes in an alternating current circuit, an electromagnet device comprising an E-shaped planar soft magnetic voltage section having a central voltage pole and two outer legs disposed in a common plane, a soft magnetic current section having current poles spaced from the voltage pole to define an air gap therebetween, voltage winding means effective when energized in accordance with an alternating voltage for directing first alternating magnetic flux through the voltage pole into the air gap, current winding means effective when energized at least in part by alternating current for directing second alternating magnetic flux through the current poles into the air gap to establish with the first magnetic flux a shifting resultant magnetic field in the air gap, an electro-conductive armature device mounted for rotation relative to the electromagnet device about an axis, said armature having a portion positioned in the air gap to develop a torque from said resultant magnetic field which acts to rotate the armature device relative to electromagnet device about said axis, said electromagnet device establishing a first magnetic path for the first alternating magnetic flux which includes the voltage pole, the outer legs, the air gap and a portion of the armaTure device, a magnetic path unit establishing a second magnetic path for the first alternating magnetic flux including a soft magnetic member magnetically linked to the face of the voltage pole and extending parallel to the plane of the voltage section adjacent the air gap, and magnetic means completing with the magnetic member the second magnetic path so as to exclude the air gap and the armature device, and a closed circuit electro-conductive unit inductively linked substantially only with magnetic flux carried by the second magnetic path to effect loading of the voltage winding means, at least one of said units being adjustable along an axis substantially parallel to the plane of the voltage section to vary the loading of the voltage winding means by the electro-conductive unit and vary the phase relationship between the first and second alternating magnetic fluxes, said magnetic means including a soft magnetic device extending from a position adjacent the magnetic member to the free ends of the outer legs to define with the magnetic member said second magnetic path which is clear of the armature device, said magnetic means directing magnetic flux between the voltage pole and each of the outer legs through the magnetic member.

Claim 3

An induction device as claimed in claim 1 wherein said adjustable one of the units comprises a soft magnetic screw having a screw axis substantially parallel to the plane of the voltage section and being in threaded engagement with a part of said magnetic path unit.

Claim 4

An induction device as claimed in claim 2 wherein said voltage and current sections are included in a watthour meter, wherein said voltage section is constructed of a plurality of E-shaped laminations each parallel to the plane of the voltage section and stacked in a direction transverse to such plane, and wherein said magnetic means comprising a soft magnetic element abutting an outermost one of the laminations.

Claim 5

An induction device as claimed in claim 1 wherein said magnetic means comprises a soft magnetic element adjacent the voltage pole and said magnetic device comprises a soft magnetic bracket extending between the free legs of the outer legs and spaced from said soft magnetic member so as to establish a third magnetic path for shunting said first alternating magnetic flux from the air gap, one of said units comprising a screw having an axis parallel to the common plane of the voltage section and operable for varying the loading of the voltage winding means by movement relative to said electro-conductive unit.

Claim 6

An induction device as claimed in claim 4 wherein said soft magnet member includes block secured to the voltage pole and wherein said screw is constructed of soft magnetic material and is operable for movement along a path extending between said voltage pole and one of said outer legs for varying the magnetic reluctance in an air gap between the bracket and the soft magnetic member to adjust said loading of the voltage winding means, the spacing between the racket and the soft magnet element constituting an air gap in said third magnetic path which directs magnetic flux away from the electro-conductive unit and the air gap including said armature device to control the torque response of the induction device to energization of the winding means.

Claim 7

In a multi-stator induction device responsive to a function of the volt-amperes in an alternating current circuit; a rotor structure having an electro-conductive armature device; a stator structure; and means mounting the rotor structure for rotation about an axis relative to the stator structure; said stator structure comprising a plurality of electromagnet devices each comprising an E-shaped planar soft magnetic voltage section including a center pole and two outer legs disposed in a common plane, a soft magnetic current section having current poles spaced from the center voltage pole to define an air gap therebetween, voltage winding means effective when energized in accordance with an alternAting voltage for directing first alternating magnetic flux through the center voltage pole into the air gap, and current winding means effective when energized at least in part by alternating current for directing second alternating magnetic flux through the current poles into the air gap to establish with the first magnetic flux a shifting resultant magnetic field in the air gap, said armature device having a portion positioned in the air gap to develop a torque from said resultant magnetic field which acts to rotate the armature device relative to electromagnet unit about said axis; each of said electromagnet devices comprising a first magnet path for the first alternating magnetic flux which includes the center voltage pole, the outer legs and a portion of the armature device, a magnetic path unit including a soft magnetic member, and magnetic means completing with the magnetic member a second magnetic path which excludes the air gap for magnetic flux produced by the voltage winding means, and a closed circuit electro-conductive unit linked substantially only with magnetic flux carried by the second magnetic path to effect loading of voltage winding means, at least one of said units being movably adjustable to vary the loading of the voltage winding means by the electro-conductive unit and vary the phase relationship between the first and second alternating magnetic fluxes, said magnetic means including a soft magnetic device extending from a position adjacent the soft magnetic member to the free ends of the outer legs to define with the magnetic member said second magnetic path which is clear of the armature, said magnetic means directing magnetic flux between the center voltage pole and each of the outer legs through the magnetic member; the movably adjustable one of said units for each of two of said electromagnet devices comprising an adjustment screw having an axis extending substantially transverse to the plane of the associated voltage section; and the movably adjustable one of said units for a third one of said electromagnet devices comprising an adjustment screw having an axis extending substantially parallel to the plane of the associated voltage section.

Claim 8

In a multi-stator induction device responsive to a function of the volt-amperes in an alternating current circuit; a rotor structure having an electro-conductive armature device; a stator structure; and means mounting the rotor structure for rotation about an axis relative to the stator structure; said stator structure comprising a plurality of electromagnet devices each comprising an E-shaped planar soft magnetic voltage section including a center pole and two outer legs disposed in a common plane, a soft magnetic current section having current poles spaced from the center voltage pole to define an air gap therebetween, voltage winding means effective when energized in accordance with an alternAting voltage for directing first alternating magnetic flux through the center voltage pole into the air gap, and current winding means effective when energized at least in part by alternating current for directing second alternating magnetic flux through the current poles into the air gap to establish with the first magnetic flux a shifting resultant magnetic field in the air gap, said armature device having a portion positioned in the air gap to develop a torque from said resultant magnetic field which acts to rotate the armature device relative to electromagnet unit about said axis; each of said electromagnet devices comprising a first magnet path for the first alternating magnetic flux which includes the center voltage pole, the outer legs and a portion of the armature device, a magnetic path unit including a soft magnetic member, and magnetic means completing with the magnetic member a second magnetic path which excludes the air gap for magnetic flux produced by the voltage winding means, and a closed circuit electro-conductive unit linked substantially only with magnetic flux carried by the second magnetic path to effect loading of voltage winding means, at least one of said units being movably adjustable to vary the loading of the voltage winding means by the electro-conductive unit and vary the phase relationship between the first and second alternating magnetic fluxes, said magnetic means including a soft magnetic device extending from a position adjacent the soft magnetic member to the free ends of the outer legs to define with the magnetic member said second magnetic path which is clear of the armature, said magnetic means directing magnetic flux between the center voltage pole and each of the outer legs through the magnetic member; the movably adjustable one of said units for each of two of said electromagnet devices comprising an adjustment screw having an axis extending substantially transverse to the plane of the associated voltage section; and the movably adjustable one of said units for a third one of said electromagnet devices comprising an adjustment screw having an axis extending substantially parallel to the plane of the associated voltage section.

Claim 9

An induction device as claimed in claim 6 in combination with a base on which the induction device is mounted extending generally parallel to the voltage section of the third one of said electromagnet devices and adjacent thereto, said adjustment screw for the third one of said electromagnet devices being intermediate the plane of such voltage section and the base.

Claim 10

An induction device as claimed in claim 7 wherein for the third one of the electromagnet devices said magnetic member comprises a soft magnetic block substantially abutting the associated center voltage pole adjacent the free end thereof and a soft magnetic bracket extending between the free ends of the outer legs and spaced from said magnetic element, said adjustment screw for the third one of the electromagnets being of soft magnetic material and being responsive to rotation for movement along its axis to adjust the magnetic reluctance between the soft magnetic block and the bracket.

Claim 11

An induction device as claimed in claim 8 wherein for the third electromagnet device said soft magnetic element is spaced from the bracket by an air gap proportioned to pass voltage magnetic flux through a path independent of the adjustment screw adjustment and independent of the first named air gap for such third electromagnet device thereby establishing a third magnetic path for said first alternating magnetic flux effective to control the torque developed on said armature device by said resultant magnetic field.