US2089696A - Dynamo-electric machine - Google Patents

Description

Aug. 10, 1937. w. E. GOUGH ET AL 2,039,696

DYNAMIC-ELECTRIC MACHINE Filed Sept. 4, 1935 Inventors WiHiam E.GOU Willi T eir- Attorn 65 3h m H.Ma cock,

afi wi Patented Aug. 10, 1937 UNITED STATES PATENT OFFICE;

2,089,696 DYNAMIC-ELECTRIC MACHINE Application September 4, 1935, Serial No. 39,151

In Great Britain September I, 1934 Claims.

Our invention relates to dynamo-electric chines. In constructing dynamo-electric machines, such as magnetos adapted to be utilized for the generation of a voltage for ignition purposes in internal combustion engines having a large number of cylinders, difficulty is encountered in 0b-- taining the proper functioning of ordinary contact breakers if a single set of coils is used, and

IQ magnetic and. electrical interference occurs between diiferent -sets of coils when more than one set of coils is used.

An object of our invention is to provide an improved dynamo-electric machine adapted to be used for ignition purposes in high speed multicylinder internal combustion engines, constructed to provide improved contact breaker operation and to eliminate magnetic and electrical interference between different sets of coils.

20 We accomplish this by providing a stator having magnetically and electrically independent sets of primary and secondary coils, each associatedwith a pair of pole-pieces mechanically spaced 180 of arc apart from the pole-pieces 25 associated with the other set of coils, and controlled by separate contact breakers operating alternately. The contact breakers preferably are actuated by separate pivoted levers, which are operated alternately by a single cam having pro- 30 jetting cam surfaces angularly displaced from each other to produce the desired timing of the machines. The rotor consists of a magnet or magnets providing two or more pairs of pole-' pieces of opposite polarity, circumferentially 3:, spaced, so that one of the pairs of rotatable polepieces cooperates magnetically with one of the pairs of stationary pole-pieces, at the same time that a diametrically opposite pair of rotatable pole-pieces cooperates magnetically with the 40 other pairs of stationary pole-pieces. Each secondary coil, preferably is connected to a separate distributor arm. These arms are driven at the same speed and in a predetermined speed relation to the speed of the magneto.

Our invention will be more fully set forth in the following description referring to the accompanying drawing, and the features .of novelty which characterize our invention will be pointed out with particularity in the claims annexed to 50 and forming apart of this specification.

For a better understanding of our invention, reference is made to the accompanying drawing wherein the single figure is a diagrammatic illustration of a magneto electric machine em- ,55 bodying our invention.

Referring to the drawing; we have shown our invention as applied to a magneto electric machine adapted to be used in the ignition system of a twenty-four cylinder engine of the fourcycle type. The stationary magnetic circuit comprises two U-shaped cores ill and H having pairs of pole-pieces l2 and |3, and l4 and I5, respectively, spaced 180 apart and magnetically independent of each other, which may be supported in any suitable manner to provide this arrangement, as in a non-magnetic frame. The electrical circuit of the magneto. comprises two sets of primary and secondary coils l6 and I1, and I8 and I9. One set ofthese' coils is mounted on each of the pairs of stationary U-shaped cores.

In this manner, each set of coils is electrically and magnetically independent of the other set and interference therebetween is effectively pre- .vented.

A voltage is induced in the primary coils IB and I8 by a rotating member comprising a permanent magnet having an axially extending permanent magnet core 20 and polar projections 2| and 22 extending axially back over the core 20 from both ends. All of the polar projections 2| are permanent magnets of one polarity, and all of the polar projections 22 are permanent magnets of another polarity and they are arranged in alternate intermeshing circumferentially spaced relation and provide pairs of rotatable poles of alternate magnetic polarity. These rotatable permanent magnet pole-pieces 2| and 22 are arranged, so that one pair of rotating poles cooperates magnetically with the pair of stationary pole-pieces l2 and i3 simultaneously when a diametrically opposite pair of rotating poles 00- operates magnetically with the other pair of stationary pole-pieces I l and Hi. This rotatable magnetic structure is mounted on a shaft 23, which may be driven in any desired manner in a predetermined speed relation to the speed of the engine. j

The primary coils l6 and I8 and the secondary coils l1 and H! are connected, respectively, to ground at 24 and 25 through contact breakers 26 and 2'1 with condensers 28 connected across the breakers 26 and 21, The contact breakers 26 and 21 are provided with pivoted levers 29 on which are mounted contact points 30 which cooperate with stationary contacts 3|. These contact breakers are normally biased into closed position by springs 32. A cam 33 is mounted on the magneto shaft 23 and is provided with four projecting cam surfaces 34 arranged to actuate the contact breakers 26 and 21 through the rollers 35, so as to interrupt the electrical circuit of the primary coils l6 and it when the corresponding distributor arm is adjacent a stationary contact.

The voltage impulses produced by the interruption of the primary circuit are distributed to the engine ignition system by a distributor provided with two sets of twelve contacts 31 and 38 to which the voltage impulses are transmitted by contact arms 39 and 40, respectively. These distributor contact arms are insulated from each other and are mounted on a shaft 4! so that they are driven both at the same speed. With such an arrangement, it is necessary that the distributor arms rotate in a predetermined speed relation to the speed of the magneto and this is readily obtained by driving the shaft ll through gears 42 and 43 from the magneto shaft 23. In the construction illustrated the shaft 4| is driven one-third of the speed of the magneto shaft 23.

Brushes II and 45, respectively, connected to the secondary coils l1 and I9 transmit the voltage impulses to insulated slip rings 46 and 41, which are electrically connected to the contact arms 39 and 0.

poles it and IS, a pair of pole-pieces 2| and 22 also rotates past the faces of the pole-pieces l2 and I3 but, since the contact breaker 26 is not at that time actuated, no voltage impulse is induced in the secondary coil l1. As the rotating magnet moves through from the position shown, the

contact breaker 28 breaks the electrical circuit of the primary coil l8 and induces a voltage impulse in the secondary coil l1. During this operation, a'pair of poles 2| and 22 rotates past the pole faces of the stationary pole-pieces l4 and it but, since the contact breaker 21 is at that time closed, novoltage impulse is induced in the secondary coil it. Thus, the voltage impulses are induced alternatively in one secondary coil and then the other upon successive displacement of 45 01' the rotatable member and, consequently, eight impulses are produced from the two coils for one revolution of the rotatable member of the magneto.

The distributor brush arms I! and III are displaced so that, as the impulse is induced in the secondary coil II, the brush arm 39 makes contact with one of the segments 31 and when the rotating magnet of the magneto has moved through 45, the shaft ll is moved through 15, thus bringing the distributor brush arm I in contact with one of the distributor segments ll. In this manner, 24 impulses are distributed to the engine with the magneto running at one and one-half times engine speed, and the distribu-' tor at half engine speed; that is, at one-third magneto speed With this type of construction, as many as sixty-four thousand impulses per minute have been produced. v

While we have illustrated and described one embodiment of our invention, modifications thereo! will occur to those skilled in the art. We

. to cooperate magnetically with said desire it to be understood, therefore, that our in vention is not to be limited to the particular arrangement disclosed and we intend in the ap pended claims to cover all modifications which do not depart from the spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. A. dynamo-electric machine including astationary member having pairs of pole-pieces, a primary coil and a secondary coil associated with one of said pairs of stationary pole-pieces, a second primary coil and a second secondary coil electrically and magnetically independent of said first mentioned primary and secondary coils associated with another of said stationary polepieces, a rotatable member comprising a permanent magnet having an axially extending core and polar projections extending axially back over said core from both ends thereof in alternate intermeshing circumferentially spaced arrangement providing pairs of rotatable poles of alternate polarity arranged to cooperate magnetically with said stationary pole-pieces, a contact breaker in circuit with said first mentioned primary coil, a second contact breaker in circuit with said second primary coil, and means for alternately actuating said contact breakers as successive pairs of said rotatable polar projections cooperate magnetically with said stationary pole-pieces.

2. A dynamo-electric machine including a stationary member having pairs of pole-pieces, a primary coil and a secondary coil associated with one of said pairs of stationary pole-pieces, a second primary coil and a second secondary coil electrically and magnetically independent of said first mentioned primary and secondary coils associated with another of said stationary polepieces, a rotatable member comprising a permanent magnet having an axially extending core and pairs of axially extending circumferentially spaced polar projections oi alternate polarity arranged to cooperate magnetically with said stationary pole-pieces, a contact breakerin cirvcult with said first mentioned primary coil, a

second contact breaker in circuit with said second primary coil, and means for alternately actuating said contact breakers as successive pairs of said rotatable polar projections are in position stationary pole-pieces.

3. A dynamo-electric machine including a stationary member having two pairs of pole-pieces, said pole-pieces being spaced 180 apart, a primary coil and a secondary coil associated with one of said pairs oi stationary pole-pieces, a second primary coil and a second secondary coil electrically and magnetically independent of said first mentioned primary and secondary coils associated with the other 01' said pairs of stationary pole-pieces, a rotatable member comprising a permanent magnet having an axially extending core and palm of circumferentially spaced polar projections of alternate polarity extending axially about said core and arranged to cooperate with said stationary pole-pieces, means including a contact breaker for controlling said first mentioned primary coil, means including a second contact breaker for controlling said second primary coil, and means including a cam for alternately actuating said contact breakers as sucv cessive pairs of said rotatable polar projections cooperate magnetically with said stationary polepieces.

4. A dynamo-electric machine including a an 15 tionary member having pairs of pole-pieces, a primary coil and a secondary coll associated with one of said pairs of stationary pole-pieces, a second primary coil and a second secondary coil electrically and magnetically independent of said first mentioned primary and secondary coils associated with another of said pairs of stationary polepieces, a rotatable member comprising a permanent magnet having an axially extending core and circumferentially spaced polar projections extending axially about said core from. both ends thereof arranged alternately to provide pairs of rotatable poles of alternate polarity, said pairs of rotatable poles being arranged so that one of said pairs of rotatable poles cooperates magnetically with one of said pairs of stationary pole-pieces simultaneously when a diametrically opposite pair of rotatable poles cooperates magnetically with the other pair of said stationary pole-pieces, means including a contact breaker for controlling said first mentioned primary coil, means including a second contact breaker for controlling said second primary coil, means including a cam for alternately actuating said con-' tact breakers as successive pairs of said rotatable pole-pieces cooperate magnetically with said stationary pole-pieces, a distributor having two sets of contacts and two contact arms, one of said contact arms being associated with one of said sets of contacts, the other of said contact arms being associated with the other of said sets of contacts, means for electrically connecting said first mentioned contact arm to said first mentioned secondary coil, and means for electrically connecting said second mentioned contact arm to said second secondary coil.

5. A dynamo-electric machine including a stationary member having two pairs of pole-pieces, said pole-pieces being spaced 180 apart, a pri- 40 mary coil and a secondary coil associated with one of said pairs of stationary pole-pieces, a second primary coil and a second secondary coil electrically and magnetically independent of said first mentioned primary and secondary coils associated with the other of said pairs of stationary pole-pieces, a rotatable member comprising a permanent magnet having an axially extending core and polar projections extending axially back over said core from both ends thereof in alternate intermeshing circumferentially spaced arrangement providing pairs of rotatable poles of alternate polarity, said polar projections being arranged so that one of said pairs of rotatable poles cooperates magnetically with one of said pairs of stationary pole-pieces simultaneously when a diametrically opposite pair of rotatable poles cooperates magnetically with the other pair of said stationary pole-pieces, means including a contact breaker for controlling said first mentioned primary coil, means including a second contact breaker for controlling said second primary coil, means including a cam for alternately actuating said contact breakers as successive pairs of said rotatable poles cooperate magnetically with said stationary pole-pieces, a distributor having two sets of contacts and two contact arms, one of said contact arms being arranged to contact one of said sets of contacts, the other of said contact arms being arranged to contact the other of said sets of contacts, means for electrically connecting said first mentioned contact arm to said first mentioned sec ondary coil, means for electrically connecting said second mentioned contact arm to said second secondary coil, and means for driving said distributor arms at the same speed and in a predetermined speed relation to the speed of said magneto rotatable member.

WILLIAM E. GOUGH. WILLIAM H. MAYCOCK.

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