US1768591A - Electrical apparatus - Google Patents

Description

July 1, 1930. M. w. FisH ELECTRICAL APPARATUS Filed Sept. 26, 1923 [UL/E172 a2" WWTQ M 5 1 Z'YErneg Patented July 1, 1930 I UNITED STATES PATENT OFFICE MORTIMER W. FISH, OF DAYTON, OHIO, ASSIGNOR TO DELCO-LIGHT COM PANY, OF

DAYTON, OHIO, A CORPORATION OF DELAWARE ELECTRICAL APPARATUS Application flled September 26, 1923. sum lie-64,834.

This invention relates to electric motors, and'particularly to motors of the induction type wherein the motor is started from rest through the agency of armature circuits including brushes and a commutator, but after a certain speed has been attained the commutator is short circuited and the motor operates as an induction motor.

The objects of the present invention include provision of speed responsive means for short circuiting the commutator and for permitting the brushes to travel with the commutator in order to eliminate needless noise and brush wear.

Other and further objects and advantages from the following description, re erence being had to the accompanyin drawings, wherein a preferred form of em odiment of the present invention is clearly shown.

In the drawings:

Fi 1 is an end view of an electric motor 3 provided with the present invention, the

end cover plate being removed.

Fig. 2 is a fragmentary sectional view taken substantially on the line 2-2 of Fig. 1, showing certain parts in normal position. Fi 3 is a fragmentary sectional view showin the parts in Fig. 2 in positions correspon ing to a certain speed of operationof the motor.

The motor includes a field which in the drawings is represented by field frame 20 within which rotates an armature provided with a commutator 21. Commutator. 21 in- 35. Plate is provided with a central aperturefor receiving the hub 28. Plate 35 may rotate with the armature or may be held in a stationary position. The means for maintaining plate 35 stationary comprises a stationary disk 36 attached to the shell 20 in any convenient manner and provided with lugs 37 located diametrically opposite and each is provided with an inwardly projecting portion 38 adapted to be received by arms 33 as shown in Fig. 1

The speed responsive means of the motor armature for short circuiting the commutator bars 22 and for releasing the brushes 7 from the device which normally maintains the brushes stationary so that the brushes may turn with the commutator after a certain armature speed has been reached, comprises a plurality of weight elements 41 pivoted at 42 upon the hub 28 and provided with rollers 43 which bear against a disk 44. From disk 44 pressure may be transmitted to the left as shown in Fig. 3 to disk 45, brush arm plate 35, disk 46, disk 47, contact 48 and s ring 49 which bears against the washer 2 l The operation of this invention is as follows: v

Normally, or when the armature is at rest, the speed responsive elements 41 are in position as shown in Fig. 2. The spring 49 maintains the parts 48, 47 46, 35, and 44 in the position shown in Fig. 2 pressed as far as possible toward the rollers 43 and the weights 41. The inward position of Weights 41 is limited by stops 41 which bear against the hub 28. The brushes 31 are connected together electrically as well as mechanically as shown so that the motor initially operates as a repulsion motor. After a certain armature speed has been attained, the weight elements 41 will move into the position shown in Fig. 3, thereb causing the contact member 48 to engage t e bars 22 of the commutator 21, and causing the brush arm plate 35 to be released from engagement by the lugs 37. Therefore, the commutator bars 22 will be short circuited and the brushes will be permitted to turn with the commutator. Since the brushes may turn with the commutator during the normal operation of the motor instead of remaining stationary, noise and brush wear have been eliminated.

The construction and arrangement of the mechanism is such that ready access may be had thereto without disassembling the motor. Since the brush retaining disc 36 is carried directly by the field frame and the short circuiting device is located at the same end of the motor and adjacent the end of the commutator, it is necessary only to remove an end cover 50 in order to have access to the mechanism. 7 The removal of the cover does not in any manner affect the operation of the motor. In this manner the attendant can view the performance of the mechanism. While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. An electric motor, comprising in combination, a rotating commutator, brushes engaging said commutator, a contact adapted to engage said commutator for short circuit ing the bars thereof, centrifugally operated weights adjacent the end of the commutator", a brush supporting member disposed between said contact and weights, said member being adapted to be moved longitudinally by the weights to move said contact into engagement with the commutator, and means for preventing the rotation of said member, said means being rendered inoperative after a predetermined longitudinal movement of said brush supporting member, whereby the brushes rotate with the commutator.

2. An electric motor, comprising in combination, a rotating commutator, brushes engaging said commutator, a contact adapted to engage said commutator for short circuiting the bars thereof, centrifugally operated weights adjacent the end of the commutator, a brush supporting member disposed between said contact and weights, said member being adapted to be moved longitudinally by the weights to move said contact into engagement with the commutator, and means for preventing the rotation of said member, said means being rendered inoperative after a predetermined longitudinal movement of said brush supporting member, whereby the signature.

MORTIMER W. F ISH.

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