Electrical device with improved heat dissipation

• US 4,496,923 A
• Filed: 09/13/1982
• Issued: 01/29/1985
• Est. Priority Date: 09/13/1982
• Status: Expired due to Term

• Current Assignee: Dana Corporation (Dana, Inc.)
• Original Assignee: The Superior Electric Co.
• Inventors: Lenzing, Richard S.
• Primary Examiner(s): Pellinen, A. D.
• Assistant Examiner(s): Steward, Susan
• Application Number:
  US06/417,027
• Time in Patent Office: 869 Days
• Field of Search: 336/59, 336/61, 336/96, 336/148, 336/149
• US Class Current: 336/59
• CPC Class Codes: H01F 29/06 with current collector gliding or rolling on or along winding

Abstract

An improved electrical device of the type having a coil and a base and having a thermally conductive electrical insulating material placed between the coil and the base so as to facilitate the flow of heat from the coil to the base, and further having a base with an extended surface area so as to promote the flow of heat from the base to the surrounding air. In one construction, the insulating material is cast in place, thus cementing the coil and the base together.

Claims

1. In an electrical device of the type having a contact brush in electrical engagement with, and relatively movable with respect to, a coil wound upon a magnetic core and mounted upon a base, the coil being separated from the base by an electrical insulator, and in which the movement of the brush varies the output of the device, the improvement comprising:

(a) employing for the electrical insulator a castable insulating material of relatively high thermal conductivity, so that heat from a hotter portion of the coil may be readily transferred to a cooler portion of the coil and to the base;

(b) employing for the base a relatively deep trough, the outer wall of which axially surrounds the coil and extends laterally over at least a portion of the coil, so that the coil may be placed therein in noncontacting relationship thereto and the castable insulating material may be placed therein, which material will fill at least the space between the coil and the base and will cement the coil to the base; and

(c) the base further including an extended surface area comprising a plurality of fingers extending from the periphery of the base and spaced so as to allow air to circulate therebetween such that heat transferred from the coil to the base may be readily transferred to the surrounding air.

2. A variable transformer, comprising:

(a) an electrical conductor wound upon an electrically insulated, annular, magnetic core to form a coil;

(b) means for moving a contact brush along an arcuate path on the surface of the coil while in electrical engagement therewith;

(c) a base having a bottom and inner and outer cylindrical walls each extending upward from the base to form a relatively deep annular trough into which a portion of the coil extends in noncontacting relationship thereto;

(d) a castable electrical insulator of relatively high thermal conductivity cast in the space between the coil and the base to cement the coil to the base and to readily transfer heat from a hotter portion of the coil to a cooler portion of the coil and to the base; and

(e) the base further including an extended surface area comprising a plurality of fingers extending from the periphery of the base and spaced so as to allow air to circulate therebetween such that heat transferred from the coil to the base may be readily transferred to the surrounding air.