Ement induction device having common armature and magnetic light-load adjusters

Claim 2

A meter as claimed in claim 2 wherein each of said magnetic members is mounted symmetrically relative to the other of said magnetic members for pivotal adjustment about a second axis parallel to the first axis and located between the magnetic unit and the axis.

Claim 3

A meter as claimed in claim 3 wherein the magnetic member is U-shaped with legs extending from the connecting web into the air gap.

Claim 4

A meter as claimed in claim 4 wherein a projection extends from one of said legs through the air gap, and means engaging the projection after it passes through the air gap to adjust the magnetic member pivotally about the second axis.

Claim 5

A meter as claimed in claim 4 wherein each of said legs has a rib projecting in each direction parallel to the first axis, whereby one of the ribs can engage an adjacent pole piece associated with said voltage magnetic flux.

Claim 6

A meter as claimed in claim 4 wherein first and second ones of said stators are angularly displaced from each other 180* about the first axis at the sides of the meter, a third one of said stators equiangularly displaced between the first and second stators, and means accessible from the front of said meter for adjusting each of the flux control means of the first and second stators.

Claim 7

A meter as claimed in claim 7 in combination with an alternating polyphase electric system, each of said stators being connected to a separate phase of the system; the connection of one of said stators being reversed relative to the connections of the remainder of the stators.

Claim 8

A meter as claimed in claim 2 wherein said magnetic member is adjacent to the armature, each of said stators comprises a second magnetic member adjacent the armature, said magnetic unit of the last-named stator being between the second magnetic member and the axis.

Claim 9

A meter as claimed in claim 9 wherein each of the magnetic units of said stators includes an E-shaped voltage soft magnetic section having a center leg and two outer legs each terminating in pole faces adjacent the armature and winding means for establishing a magnetomotive force between the pole face of the center leg and the pole faces of the outer legs in parallel, said pole face of the center leg being substantially surrounded by each of the associated magnetic members for reducing interferring leakage flux thereof, said second magnetic member having its ends magnetically coupled to said outer legs and being spaced from the center leg, and adjustable soft magnetic means for adjusting the magnetic coupling between the second magnetic member and the center leg.

Claim 10

A meter as claimed in claim 10 in combination with a separate magnetic shunt extending between the axis sides of the outer legs of each of the stators adjacent the armature, each of said shunts extending adjacent, but spaced from the associated center leg to shunt voltage magnetic flux between the associated center and outer legs and thereby further reduce said interferring leakage flux.

Claim 11

A meter as claimed in claim 10 wherein said adjustable magnetic means comprises first and second magnetic screws each adjustable for varying the magnetic coupling through the assoCiated screw between the second magnetic member and the center leg, and an electro-conductive element substantially surrounding one of the screws.

Claim 12

A meter as claimed in claim 1 wherein said armature comprises a plurality of electro-conductive disks having said first axis as a common axis, the disks being laminated together and insulated from each other, each of said disks having a plurality of angularly spaced radial slots, the slots of each disk being angularly spaced about the first axis from the slots of the remainder of said disks, each of said magnetic units having an E-shaped voltage section defining an inner pole piece and two outer pole pieces, said voltage winding means when energized establishing a magnetomotive force between the inner pole piece and the two outer pole pieces in parallel, a soft magnetic bracket extending across said outer pole pieces adjacent the air gap, the pole pieces being between the bracket and the first axis, means establishing a path for magnetic flux between said bracket and the inner pole piece, and power-factor control means responsive to magnetic flux traversing said path.

Claim 13

A meter as claimed in claim 13 in combination with a soft magnetic shield for the voltage section of each of said stators.

Claim 15

A method as claimed in claim 15 wherein first and second ones of the stators are spaced substantially 180* from each other about the axis, and a third one of the stators is spaced substantially 90* from each of the first and second stators, and any one of said first, second and third stators is effective for producing said desired light-load torque.

Claim 16

A method as claimed in claim 16 in combination with the step of connecting the windings of the stators to energize the second stator in reverse directions relative to the energizations of the windings of the first and third stators.