US2184236A - Prime mover dynamo plant - Google Patents

Description

1 'uw 19,1939. RM. HEINTZ 2,184,236

rimas ovan Dmo PLANT l Fild Nov. 5, 1938 2 sheets-sheet 1 INVENTOR.

R. M. HEINTZ lPRIME: HOVER DYNAIO PLANT I l l` Filed Nav. 5; 193s `2 Sheets-Sheet 2 Ac LOAD INVENTQR.

` l t N l I* l 4 -ATT NlawfdI Patented Dec. `19, 1939 UNITED STATES PATENT lOFFIGE PRIME Movna DYNAMo PLANT Ralph M. Heinta, Montclair, N. assigner to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application November 5, 1938, Serial No. .239,091

13 Claims.

This invention relates to a combined starting and generating unit for use with internal combustion engines and capable of functioning first. to start an internal combustion engine byappiication of torque thereto, and thereafter to. convert the power developed in the engine into elecmultiple purposes including, for example, the

. initial turning over, or cranking. of an internal combustion engine, and the subsequent generation of alternating current of high frequency, by

I 'conversion of mechanical energy transmitted thereto by way of said internal combustion engine.

Among the novel featuresof the machine herein disclosed there is included thatof a commutator adapted to be engaged by rotatable brushes, for transmission of currentbetween the former and the latter at relatively low rotor speeds, the invention further including the concept of a novel method of manufacturing said commutator, and, a novel mounting and mode of operation forsaid rotatable brushes, as a result lwhereof the said brushes remain in engagement with the commutator to feed low voltage direct current to the stator windings during the duration of the engine cranking operation, but move outof engagement and thereby discontinue such direct current fiowas soon as the engine crank-shaft accelerates sufliciently to render further cranking unnecessary. Thereafter the. stator.- serves solely as a supply ci alternating current for outside points of distributionand consumption.

These and other objects and features of the invention will become apparent upon consideration of the following detailed description, and upon reference .to the accompanying drawings illus-l trating the preferred embodiment of the invention. It is tov be understood, however, that the drawings are illustrative only, and that the calims at the conclusion of the specification, rather than the drawings, measure the scope of the invention.

In the drawings, wherein like reference characters refer to like parts throughout the several views:

Fig..1 is a longitudinal sectional view of va housing enclosing a machine embodying the invention, some of the enclosed parts being shown in section and some in elevation;

Fig. 2 is a diagram of the electrical connections for the machine of Fig. 1 and including a schematicv representation ofthe speed responsive brush shifting means.

Fig. 3 is a view showing part of the communates a source of direct current (battery, for xample) and II designates an alternating current receiving apparatus, such asradio transmitters,

transformers, receivers, rectiflers, motors, etc., to which alternating currentof high frequency may be supplied upon rotation, at relatively high speed, of an engine drivendynamo-electric m'a\ 'chine whose rotor shaft I2 is shown as directconnected to the crank-shaft I3 ofan internal combustion engine A(notfully shown). Engines of a character adapted to drive high Afrequency alternators are commonly employed on aircraft as a power supply means for operation of electrical equipment of which the units above en'umerated may be taken as examples.

Such aircraft4 installations ordinarily include -a battery such as that shown at IB, charged at sufiicient capacity to energize the rotor and stator 4 windings IB and I1, respectively, 4for usetas a,"

starting motor in the initial cranking and acceleration of the engine crank-shaft I3 to selfsustaining speed. Attainment of this normal running speed produces a centrifugal force of suiiicient magnitude to raise rotor brushes Il., I9, 20, and 2l out of contact `with commutator 23, lwhereupon the passage of current therebetween is interrupted.` Thereafter stator windings I1.\ serve solelyas a source of alternating current,

said brushes being in turn connected lwith co1- lector ring 33 of positive polarity while the other their e'nds'to brushes I8, I9, 2li and 2|, two of` n two connect with collector ring 34 of negative polarity. Brushes 36, mounted in brush assemblies secured to the housing 4I by suitable means (of which that shown at 42 in Fig. 1 is an example) engage collector ring 34, while brushes 31, correspondingly mounted, engage collector ring 33. Conductors 43 and 44 complete the connections from battery Ill to the stationary brush sets, while a conductor 28 connects each of the rotating brushes I8 to 2l lwith its corresponding collector ring. 1

As hereinabove indicated, the stationary commutator assembly is made in a novel manner, yincluding (as a step inthe process) the union of two annular metallic members 23. and 21, of which the former eventually becomes the segmented commutator, per se,v while the latter is the supporting core that is eventually secured to the housing by suitable means 29. A molding compound 30 is the uniting element for parts 23 and 21, the latterbeing provided, if desired, with compound receiving holes 41 to insure more complete union therebetween.

A preceding step in the process is to cut slots 48 (Fig. 4) extending part-way through the metallic annulus 23, and spaced around the inner periphery thereof, in accordance with a predetermined formula, to provide pockets for receipt of segmentsll (Fig. 5) of mica or equivalent insulating material. The annulus 23 (after union with core 21 in the manner above described) is machined down to finished shape, (Fig. 6) in which process all 'metal located beyond (and, if desired, additional material within) the Iradially outermost part of the mica segments 50 (see line 51Fig. 4) -is removed, thus exposing the mica edges to view, at the outer side, and likewise resulting in the creation of a corresponding number of spaced conducting segments to constitute the commutator. As shown each segment thereof has a iinalshape as indicated at 52 in Fig. 6, and each of said segments has now vbecome electrically separate from every other 'between the conductors metallic part.

By this process of fashioning the commutator segments in situ, and from asingle piece of metal, there are eliminated all problems of` accurate fitting and 'positioning of segments individually;

each" segment is automatically caused to appear in its proper relative position, since all remain unshiftable from start to finish of the process.

In order to oifset -any tangling tendency, as I5 and the rotating brush assemblies, I provide radially extending ribs forming pockets 40 in the housing 4I, along which pockets the conductors I5 are run, and to which they may be secured, thus preventing their dropping inwardly into contact with the brush assemblies i8 to 2|.

For claims to the construction of the. commutator and. other parts ofthe dynamo-electric machine, per se', reference may be had to my divisional application No. 216,191, filed May 27,

What I claim is:

1. In an internal combustion engine power plant, a dynamo-electric machine having a stator winding to deliver alternating' current and a rotor integrated with the engine crank-shaft to impart initial rotation to said crank-shaft when current is fed to the rotor and stator windings responsive to acceleration of said crank-shaft to a predetermined speed.

2. In an internal combustion engine power plant, a dynamo-electric machinehaving a stator winding to deliver alternating current and a rotor integrated with the engine crank-shaft to impart initial rotation to said crank-shaft, means including a commutator and brushes engageable therewith to feed direct current to said stator windings during the engine cranking period, and means for interrupting the feeding of current to said stator windings, said means being responsive to acceleration of said crankshaft to a predetermined speed.

3. The combination with an internal combustion engine of an alternating current generator rotatable therewith, and means for converting said generator into a continuous current shunt motor by which to impart initial rotary movement to the engine.

4. The combination with a dynamo-electric machine of the alternator type,of an external source of direct current, and means including brushes rotatable with said machine to convert it into a shunt motor receiving energy from said external source during low speed rotation oi' said brushes. v

5. The combination with a dynamo-electric machine operable as an alternating current generator at high speeds, of means including centrifugally shiftable brushes for operating said machine as a direct current receiving shunt motor at low speeds.

6. In a dynamo-electric machine having stationary and rotatable windings, means including a stationary commutator and liftable brushes engageable therewith to feed current, toL one of said windings at low speeds, and means responsive at ya. higher speed to lift said brushes away from `said commutator.

7. In a dynamo-electric machine having cooperating windings, means including a stationary commutator and liftable brushes engageable therewith to feed current to one of said windings at low speeds, and means responsive at a higher speed to lift said brushes away from said commutator.

8. In' a dynamo-electric machine having stationary and rotatable brush sets, and stationary and rotatable windings, means for feeding current to both the stationary and the rotatable windings at relatively low speeds, said means including both said stationary and said rotatable brush sets, and means mounted adjacent said rotatable brush sets for interrupting the circuit to said stationary windings as soon as the machine attains a predetermined speed.

9. In a dynamo-electric machine having stationary androtatable brush sets, and stationary and rotatable windings, means for feeding current to both the stationary and the rotatable windings at relatively low speeds, said means including both said stationary and said rraatable brush sets, means mounted adjacent said rotatable brush sets for interrupting the circuit v to said stationary windings as soon as the machine attains a predetermined speed, and a current consuming device in circuit with both said stationary windings and said rotatable brush. sets, during low speed rotation, and also remaining in circuit with said stationary windings during high speed rotation.

l0. In a dynamo-electric machine having stationary and rotatable brush sets, and stationary and rotatable windings, means for feeding current to both the stationary and the rotatable windings at relative low speeds, said means including both said stationary and said rotatable brush sets, means mounted adjacent said rotatable brush sets for interrupting the circuit to said stationary windings as soon as the machine attains a predetermined speed, and a current consuming device in circuit with both said stationary windings and said rotatable brush sets, during low speed rotation, vand also remaining in circuit with said stationary windings during high speed rotation, said current consuming device being of suiiicient resistance to prevent substantial'short-circuiting of said stationary windings, during such low speed rotation, and being further adapted to receive full energization from said stationary winding during such high speed rotation.

11. In a dynamo-electric machine having stationary and rotatable windings, means including a stationary commutator and rotatable brushes engageable therewith to feed current to said sta.- tionary windings at low speeds, and means responsive at a higher speed to lift said brushes away from said commutator.

, 12. In a dynamo-electric machine having stationarby and rotatable windings, means including. a stationary commutator and liftable brushes .engageable therewith to feed current to said stationary windings at low speeds, and means responsive at a higherspeed to lift said brushes away from said commutator.

13. Ina dynamo-electric machine having stationary and rotatable windings, means including a commutator and liftable brushes engageable therewith to feed current to said stationary windings at low speeds, ancl means responsive at a higher speed to lift said brushes away from said commutator.

RALPH M. HEINTZ.

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