Michael R West

US Patent:

52948749, Mar 15, 1994

Filed:

Aug 13, 1992

Appl. No.:

7/929791

Inventors:

Jeffrey C. Hessenberger - Waukesha WI
Michael R. West - Hartland WI

Assignee:

Milwaukee Electric Tool Corporation - Brookfield WI

International Classification:

H02P 300

US Classification:

318759

Abstract:

A universal electric motor having an arbor mounted on a rotating armature with a run winding for generating a magnetic field having a polarity relative to the armature and for rotating the arbor, a first switch for connecting the run winding to a power source, and a brake winding for generating a counter magnetic field opposed with respect to the armature winding to that generated by the run winding. The brake winding operates when energized, to stop rotation of the arbor by generating a counter magnetic field which interacts with the magnetic field of the armature Also included is an electrical circuit for providing a residual magnetism in the stator iron to help stop the arbor rotation The circuit includes an energy storage capacitor for providing current to the brake winding thereby helping to begin generation of the counter magnetic field, a second switch for connecting the energy storage to the brake winding when the first switch disconnects the run winding from the power source, a biasing diode for biasing the energy storage capacitor to a predetermined polarity, a rectifying resistor and diode for coupling the energy storage capacitor to the power source and an alternate discharge path for discharging the energy stored in the event that the normal discharge path is inoperative.

US Patent:

51534495, Oct 6, 1992

Filed:

Aug 28, 1990

Appl. No.:

7/574296

Inventors:

Fred Crook - Waukesha WI
Michael R. West - Hartland WI
Gino P. Domenella - Brookfield WI
Kevin Glasgow - North Fond du Lac WI

Assignee:

Milwaukee Electric Tool Corporation - Brookfield WI

International Classification:

H05K 720

US Classification:

307 66

Abstract:

An electronic circuit device includes a metallic member composed of a thermally and electrically conductive material and comprising a unitary mass defining a heatsink and being free of mechanical or electrical transition joints. Electronic switching devices are mounted on the member and in electrical and thermal contact therewith. A control circuit and a conductor are each mounted on the member and adjacent the switching circuit devices and electrical conductors interconnect the switching circuit devices with the control circuit. The control circuit and the conductor are thermally and electrically isolated from the metallic member. The metallic member comprises a heatsink for the electronic switching devices and a conductor for currents being switched thereby.