Electrical generator or motor structure – Dynamoelectric – Rotary
Patent
1984-09-24
1988-07-05
Skudy, R.
Electrical generator or motor structure
Dynamoelectric
Rotary
310 46, 310156, 310 43, 310 40MM, 310 46, 310156, 310254, 318254, H02K 1100
Patent
active
047556994
ABSTRACT:
Designed especially for hand-held dictation devices the motor has a three-phase external stator and two-pole permanent-magnet internal rotor, the two enclosed by an external housing from one axial end of which the rotor shaft projects out, its other axial end provided with a thrust bearing for the rotor shaft's other end. At least one Hall element, although more typically three, is provided, located at the peripheral edge of one of the axial ends of the rotor to sense axially emanating stray rotor flux. The rotor is directly secured to the rotor shaft, the shaft being ferromagnetic and near its outwardly projecting end provided with a ferromagnetic bearing mounted in a ferromagnetic end plate, so that stray flux sensed by the Hall element can travel from the rotor to the Hall element along a magnetic circuit for such sensed stray flux, but with the magnetic circuit being made up of motor components and structural parts that are required anyway. At least the radially outer part of the stator iron, serving as yoke for conducting motor flux circumferentially along the stator, is constituted by a stack of sheet-metal sheets. The stator iron may be a hollow cylinder at whose inner periphery is provided an annular, cylindrical winding constituted by a continuously wound conductor of uniform conductor-density but provided with angularly spaced taps to form the three phases, or the stator iron may have three radially inwardly extending T-shaped salient poles each carrying a stator-winding coil, with the radially innermost part of the T-shaped salient pole being a pole-shoe plate having circumferentially extending, axially spaced, comb-like slits, with all pole-shoe plates being mounted on a plastic carrier for simultaneous installation of all of them as a single unit. Each phase is energized twice per rotor rotation, with current of a first direction during a respective first half-rotation and then with current of opposite direction during the next half-rotation, to maximize the power-to-weight ratio, this being done using a full-bridge energizing circuit for the three phases.
REFERENCES:
patent: 3467847 (1969-09-01), Faulhaber
patent: 3644765 (1972-02-01), Janson
patent: 3845334 (1974-10-01), Harada et al.
patent: 4394594 (1983-07-01), Schmider
patent: 4468595 (1984-08-01), Yaebashi
patent: 4532461 (1985-07-01), Crook
Koss, Jr. Theodore J.
Papst-Motoren GmbH & Co KG
Skudy R.
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