Rotary power transformer

• US 3,924,174 A
• Filed: 03/26/1975
• Issued: 12/02/1975
• Est. Priority Date: 03/26/1975
• Status: Expired due to Term

• Current Assignee: Charles J. Fahrner
• Original Assignee: Charles J. Fahrner
• Inventors: Fahrner, Charles J.
• Primary Examiner(s): Kozma, Thomas J.
• Application Number:
  US05/562,029
• Time in Patent Office: 251 Days
• Field of Search: 336/117,118,119,120,178 323/60,53
• US Class Current: 323/362
• CPC Class Codes: H01F 38/18 Rotary transformers

Abstract

This invention relates to a Rotary Power Transformer, wherein Primary and Secondary windings on a laminated ferromagnetic core are provided, the construction permitting one winding to be rotatable with respect to the remainder of the transformer. This makes possible electrical energization of a rotatable load from a stationary source of electric power, without slip rings or sliding contacts being used. In the application of the invention to a transformer, a laminated ferro-magnetic core having a divided core leg with an air gap between core leg portions is used. A rotatable winding, secondary as a rule, is mechanically coupled to a rotatable hollow shaft passing through the core leg portions and air gap for accommodating leads between the secondary winding and rotatable load, the shaft and load being rotated by some independent means such as a motor. The primary winding is stationary, surrounds the secondary winding, but clears the same for relative rotation. The transformer functions in conventional fashion independently of secondary winding rotation. Any desired power level may be handled by suitable transformer design.

Claims

1. A transformer having a ferro-magnetic laminated core including a leg having two aligned leg portions with an air gap therebetween, a cylindrical secondary winding structure positioned over said two leg portions and air gap so that it is rotatable about the same, a shaft within passages through said aligned leg portions and through said air gap and extending through passages in said magnetic core and beyond the core, means in said air gap securing said secondary winding structure to said shaft, said secondary winding having leads extending therefrom and passing radially in said air gap to said shaft, at least part of said shaft being hollow from said air gap region to aN end of said shaft, said shaft at the region of said air gap having at least one opening through its wall to the interior thereof, said secondary winding leads extending through the shaft wall to the interior thereof and thence to the end of the hollow shaft portion for connection to a rotatable electric load, a stationary primary winding having a cylindrical interior surface disposed about said secondary winding and clearing the same to permit relative rotation thereof, both of said windings lying over the leg portions and air gap, means for retaining said core structure and primary winding rigidly in stationary position, bearing means supported by said stationary structure for rotatably supporting the shaft, said bearing means and support therefor having means for adjusting said shaft means to center the rotatable portions of the transformer for free rotation, whereby a relatively stationary electric power source may be metallically connected to the primary winding for energizing the same and the electric power in said secondary winding may be directly connected to a rotatable electric load without interposition of sliding contacts between relatively rotatable parts.

2. The construction according to claim 1, wherein the leg portions of the divided leg are shaped to provide a cruciform section for improving efficiency.

3. The construction according to claim 1, wherein the secondary winding structure includes a bobbin having the general shape of two cylindrical cups in back-to-back relation, said cup bottoms being shaped to accommodate the rotatable shaft therethrough, said cups being large enough to clear the outside of the divided magnetic leg portions about which said cups are adapted to rotate, said cups also having small sleeve portions through the rotatable shaft passes, said sleeve portions being short enough and thin enough to secure firm adherence to the rotatable shaft but clearing the opposed stationary surfaces of the core leg portions.

4. The construction according to claim 1, wherein passages for the rotatable shaft are square in section within the transformer core structure, said passages being defined by square tubes extending through the lamination portions only, the orientation of said square tubes being such that two opposed tube sides are parallel to the length of laminations while the remaining two opposed tube sides are perpendicular to the edges of laminations, said tubes providing stop limits for the ends or sides of laminations, said square tubes being large enough with respect to the diameter of the shaft so that sufficient clearance is provided to permit centering of such shaft with respect to the entire transformer construction.

5. The construction according to claim 1, wherein means are provided for power factor correction, said means including an auxiliary primary winding disposed over the first named primary winding and connected through a capacitor across the primary winding.

6. The construction according to claim 1, wherein a frame construction is provided for rigidly supporting the core and primary winding structure in rigid relation to each other and wherein end plates adjustable secured to said frame are provided for supporting bearings through which the rotatable shaft ends pass, said adjustment permitting proper centering of the rotatable portion of the transformer with respect to the stationary portion of the transformer.