Permanent magnet field motor with radio frequency interference suppressing capacitor
AssigneeStackpole Limited
InventorEdward J. Zelt
Life of this patent
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Abstract
The permanent magnet fields encircling the armature of a direct current motor are encircled by a pair of radially spaced cylindrical metal members separated by a cylindrical dielectric member. One of the metal members and one of the brushes that engages the commutator of the motor are grounded. The other brush and the other cylindrical metal member are connected to a direct current power supply, whereby a capacitor is formed by the three cylindrical members for suppressing radio frequency noise generated by sparking of the brushes at the commutator.
Claims9
A direct current permanent magnet field motor comprising an armature, permanent magnet fields encircling the armature and spaced therefrom, a commutator connected to one end of the armature for rotation therewith, a pair of brushes engaging the commutator, a pair of radially spaced substantially cylindrical metal members encircling said permanent magnet fields, a substantially cylindrical dielectric member between the two metal members, means for grounding one of said metal members and one of the brushes, and means for electrically connecting the other brush and the other metal member with a direct current power supply, whereby a capacitor is formed by said pair of metal members and said dielectric member for suppressing radio frequency noise generated by sparking of the brushes at said commutator.
Dependencies are inferred from the claim text.