MOTOR-TACHOMETER

• US 3,790,832 A
• Filed: 02/03/1972
• Issued: 02/05/1974
• Est. Priority Date: 02/03/1972
• Status: Expired due to Term

• Current Assignee: Labinal Components and Systems, Inc.
• Original Assignee: Jayant K. Patel
• Inventors: Patel, Jayant K.
• Primary Examiner(s): Skudy, R.
• Application Number:
  US05/223,089
• Time in Patent Office: 733 Days
• Field of Search: 310/113,68,114,112,154,126,233,236,237,171,177,DIG.6 318/313,327
• US Class Current: 310/113
• CPC Class Codes: G01P 3/488 delivered by variable reluctance detectors
• CPC Class Codes: H02K 7/20 Structural association with auxiliary dynamo-electric machines, e.g. with electric starter motors or exciters

Abstract

A combined motor and tachometer in a single housing incorporates an axial commutator for the motor and a radial commutator for the tachometer, in back-to-back relation, providing a maximum length reluctance path between the field for the motor and the field for the tachometer, and also between the armature of the motor and the armature of the tachometer. In this manner, the relatively sensitive tachometer is effectively isolated from adverse affects of the relatively heavier motor field.

Claims

1. A combined motor and tachometer comprising a drive shaft, separate motor and tachometer armatures mounted in axially spaced relation on said shaft, motor housing means surrounding said armatures and rotationally supporting said shaft, a pair of correspondingly spaced fields associated with said housing means one each for each of said armatures, a drum-type motor commutator on said shaft positioned in the space between said armatures adjacent said motor armature and having an axial commutating surface, disk-type tachometer commutator on said shaft in the space between said armatures positioned adjacent said tachometer armature and being formed with a radial commutating surface, said radial surface facing away from said axial commutating surface and toward said tachometer armature, and said tachometer commutator being formed with a radial diameter which exceeds the diameter of said motor commutator for isolating, and providing mechanical protection of, said tachometer commutator from said motor commutator, said tachometer field including a permanent magnet in surrounding relation to said tachometer, a combined magnet retainer and brush holder having an encircling yoke portion supporting said magnet and further having a pair of axially extending brush holder portions, means mounting said retainer on said housing at said brush holder portions, and means in said brush holder portions slidably receiving a corresponding pair of axially movable brushes for coaction with the radial face of said tachometer commutator.