USRE14181E - Assighos - Google Patents

Description

1. B. FRAWLEY.

MAGNET() ELECTRIC MACHlNE. APPLlcAlou msu ML2 Reissued Aug. 15, 1916.

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UNITED STATES PATENT OFFICE.

JAMES B. FRAWLEY, OF PIT'ISFIELD, lv'lASSACHUSE'IITS, ASSIGNDR, BY MESNE ASSIGN- MENTS, T0 BERKSIIIRE MAGNETO COMPANY, 0F PITTSFIELD, MASSACHUSETTS.

Mestiere-ELECTRIC MACHINE.

Speccaton of Ressued Letters Patent. Reissued Aug, 15, 1916.

Original No. 1,160,995, dated November 16, 1915, Serial No. 674,520. Application for-reissue led March 23,

To all whom t may concern.'

Be it known that I, JAMES B. Fitawmir, a citizen of the United States, residing. in the city of Pittsfield, county of Berkshire, and State of Massachusetts,- have invente certain new and useful Improvements in lVlagneto-Electric Machines, 'of which the "following is al speciication.

This invention relates to improyements in magneto electric machines or ignition purposes of the type shown in the United States Letters Patent issued to Theodor M. Mueller on December 21, 1909, numbered 943,697, and on May 24, 1910 numbered 958,754, in which a movable sleeve member is interposed between the pole-pieces of the permanent magnets and the softliron laminated core pieces which stand in a plane at right angles to the plane of the soft iron pole-pieces. The present invention has for one of its objects to dispense with this movable sleeve member, whereby the efficiency of the machine is materially increased. y.

A further object of the invent-ion is to lessen the demagnetizing eEect of eddy currents which are produced in the non-magnetic members that support the laminated core pieces.

In magnetos of the type shown in the above referred to patents, particularly patent numbered V943,697 December 21, 1909, (in which the sleeve member is adjustable)` the occurrence of the spark may be varied; or, in other words the spark may be advanced or retarded with relation to the angular position of the shaft. l u

It is sometimes desirable to use ignition machines in which the occurrence of the spark, with relation to the angular position of the inductor, is or may be always fixed. In order to accomplish this object, it is found that the' sleeve member vmay be entirely omitted without destroying the eiliciency of the machine when used for ignition purposes. In practice, however, it-is discovered that the electrical 'efficiency iis materially increased over -the structures shown in the above mentioned patents.

The removal of this sleeve member therefore causes the machine to produce a sparkat practically the same angular position of the rotatable inductor element, fand at the sanietime lessons the cost of construction and increase its efficiency.

In order to accomplishthe objects above Serial No. 86,321.

set forth, I have discovered that by electrically-insulating the interruptor box or casing from the core-pieces, the pole-pieces,

flow of eddy currents which are generated in the interrupter box or casing is prevented, and thereby greatly increasing the out-put or efficiency of the machines as will be fully set forth.

In the drawings forming part of this application: Figure 1 is' a longitudinal, sectional view of the magneto on the line 1--1, of yFig. 2, taken through the axis of the inductor shaft, clearly showing the machine with the movable sleeve member omitted, and the electrical insulation element located between the interrupter casing or bearing box and the core-members; Fig. 2 is atransverse sectional view on the line 2-2 of Fig.

1 showing the arrangement of the poles'of` the permanent magnets and those of the soft iron laminated core-pieces, also the rotating inductor member carried bythe shaft.

Referring designates the permanent ing the soft iron pole or face pieces b, and b1, pieces of brass to support the laminated core pieces.

o designates a shaft to which are secured the soft iron arc-shaped inductor members d. The indicator members al are rotatably'supported by means of the two casings and 02 which carry ball bearings, that are located respectively, at the inner and outer ends of the rotatable supporting means of` the inductors of the machine, as shown. The

laminated core-pieces are arranged at 90- from the pole pieces b. The former pieces extend parallel in Fig. 1 and as in the above referred to patents, their outer ends are connected by the core f of the induction coil which is designated as a whole by the letter g,-the primary and secondary windings of which are shown V'at-f1. and '12.

The electrical connections to Athe windings of theinductorcoils are not shown as of the present they do notv formA any part invention.

The arc-shaped inductor members l are rigidly clamped between the disk pieces y and c, necessarily composed of some 4nonmagnetic material, as brass or'bronze in order to prevent-a' closed magr ic circuit through the cores e and indi' tor members with theshaft c, as showny and the Yholders of the pole-pieces, that the to the drawings, in detail, a

'field magnets havico ' other Words bythe use of .a current will 'not'bepermitted to flow from' d. If the disk c is composed of magnetic material it is clear that the vpath of the lines of force would be closed through this disk and not through theqcore or, in other lWords the magnetlc lines of force would form a closed short magnetic circuit through the nductor, members d and the-disk le if this disk wasv composed of magnetic material. lThe eiciency of the machine would, therefore, be greatly reduced and practi- 4cally inoperative since the magnetic flux 'would then be short circuited through lthe disk k, instead of-causing the magnetic lines efforce to How through thecore f, as they would be forced to do, if the disk k is composed of some non-magnetic material.

m indicates a cam element through which passes a screw n for attaching the same to the rotating shaft.

Suitable timing devices may be employed in connection With the usual make and break mechanism which are operated by the cam m whereby the occurrence' of the spark in the secondary may. be advanced or retarded.

The induction coil g is axially spaced from the soft iron arc-shaped inductor members d by means of the interrupter casing or bearing box. This casing or boX is electrically insulated from the pole-pieces o and its holders 6 by means of the insulation shown at 0". The object and purpose of the insulation o is to prevent the HOW of electric currents in the pole-pieces b, and its holder b due to the potential generated in the casing o1-,bearing box o. It is clear that when the laminated inductor members d are rotated, the' casing or bearing box o will be subjectedv to an, yalternating' magnetic flux from one core member e to the other. .This alternating -lux will generate a voltage in the metal casing or bearing box o, and, if this box is not insulated from the pole-piecesb and their holders b an electric current will flow through these parts, with a result that a magnetic field, due to V be setup which will oppose the tlowof the magnetic 4flux in the core-pieces e, or, 1n the insulation o',

the casing or bearing box o through the pole\ pieces ZJ, their holders bf, and any external parts of the inachine, for example, the field magnets, thus completing a closed electrlc circuit which current would set up a counter magnetic field that Would oppose the flux in the core-pieces c and thus lessen -the efficiency of the machine.' On account `of the magnetic iiux alternating from one core c to the other core e across and around the metal casing or bearing box o and the adjacent metal parts of then-.machine as the metal base on which the' machine rests, suiiicient voltage would be produced to generate an electric current which, if not prevented by insulation in some portion o its sulation o.

, shown this current Will' shaped members circuit Would set up a' counter magneto motive force reducing the eticiency and capability of the machine. The eddy electric currents generated by means of this magnetic linx in the box 0 andthe flux produced by the same would oppose the .flux in the core 6;@ with the result thatl the current generated in the coil g would be very much less. Therefore, in order to prevent the flow of these eddy currents the insulation shown at 0 is provided. This insulation as shown is located in the most convenient part of the circuit ofthe eddy currents, that is between the casing or bearing box 0 and the cores e, e. The flux path for the magnetic lines of force Will, therefore, be largely confined to the parts CZ, e and '/i, the flux liowingin alternate directions, as the arcshaped members cl are rotated in succession past the north and south poles of the magnets (1..' Also the pieces b are maintained in a cooler condition as eddy currents can not circulate through the pieces of in- This construction produces an increased etliciency over the construction in the above mentioned patents wherein the adjustable sleeve is used, as it cuts down the air gaps, and also reduces the losses caused by eddy' currents in the masses of iron composing the adjustable sleeve. It is clear that any mechanical structure which is composed of conductive material and that is located in a position which is approximate to the casing or bearing box o as the cam m, screw n and disk c 19@ must be thoroughly insulated from the cores c, ns described, in order to accomplish the results sought or the idea in-mind, or, in other Words to prevent the flow of an electric current through the casing or box o 105 and the adjacent metal parts which are composed of conductive material.

The means for distributing and delivering the secondary current to the-spark-plugs by the magneto forms no part of my.4 invention 110 and the description oi" the same is not, therefore included. v

In the operation of the' machine, When the shaft c is rotated, the soft iron members d pass in successionpast the members and 115 e and serve as a means to alternately convey the lmagnetic flux from the poles of the permanent magnets ato thecore-pieces e in the manner fully described in the above referred .to patents, with the result that 'a 120 spark` current is induced in the secondary winding z' when the primary' is opened byl the timer inthe usual manner. l

Tt will be noticed that the soi-t iron arcd serve to` directly convey 125 the magnetic flux from the permanent magnets fr. to the core-pieces e Without the intervcntiou of the adjnstable-'sleeve member in the above referred to patents, with' the resuit, that thc spark is alwaysproduced at the 13 from the core-pieces, whereby I ductor This construction limits and confines Athe magnetic fiux eld to this portion of the machine t-hat is spaced away from the permanent magnets and also servesto increase the efiiciency of the machine.

What I claim is: 1. A magneto electric machine of the inalternator type,` in combination, a

field magnet, a pair of core-pieces, non-magnetic means 'to support the saine, inductor' members to conve)7 the magnetic flux from the field magnets to the core-pieces, said core-pieces having projecting ends, an induction coil located between saidl ends, a casing located between the core-pieces, means to electrically linsulate 'the casing the eddy currents that may be generated in the casing will be prevented from fiowing in a closed electric circuit inter-linking the core pieces and opposing the flow of flux from the permanent field through the core-pieces, as described.

2. A magneto electric machine of the type described, in combination, permanent magnets to pioduce'a constant field, core pieces to receive the flux from the permanent magnets, an induction coil arranged between the ends of the core-pieces, inductor means to directly and alternately convey the flux from the constant field to the core-pieces, a casing located between the core-pieces, means to prevent the flow of eddy currents in a circuit comprising the said casing, whereby the deinagnetizing effects due to such eddy currents in the casing are prevented.

3. The combination, in a magneto electric machine, of a. rotatable inductor member, permanent magnets, pole pieces secured thereto, core-pieces angularly spaced from the pole-pieces, holders therefor, an induction coil having its core located between the ends of the core pieces, an interrupter or cir-v cuit breaker casing located between the corepieces, means for insulating said casing, thereby preventing the' How through said casing of eddy currents induced therein whereby the magnetic flux in the corepieces is not opposed thereby.

' field magnet,

, means to prevent the flow 4. Avmagneto electric machine of the inductor alternator type, in combination, a core-pieces, non-magnetic means to support the same, inductor members to convey pieces having projecting ends, an induction coil located between said ends, acasing 1ocated between the core-pieces, means to elec-l trically insulate the casing and said supporting means from the core-pieces, whereby tlie electric currents that may be generated in the casing and adjacent metal parts of the machine will be prevented from flow- -ing in a closed electric circuit interlinking the core pieces and opposing the flow of flux from the permanent field through the corepieces, as described.

5. A magneto electric machine described, in combination, magnets to pro duce a 'constant field, core-pieces to receive the flux from the magnets, an induction coil arranged between the core pieces, inductor of the type means to directly and alternately convey the fiuX from the magnets to the core-pieces, a casing located between the core-pieces, of eddy currents in a circuit comprising said casing, whereby the demagnetizing efiect, due to such currents in the casing is prevented.

6. Thecombination, in a magneto-electric machine, of a rotatable inductor, permanent .magnets, pole-pieces, secured thereto, hold-- ers therefor, an induction coil'having its core located between the core pieces, a casing located between the core-pieces, means for electrically insulating said casing or box, whereby the electric currents that are generated in said casing may be prevented from forming a closed circuit including said casing, as described, and the magnetic fiux in the core-pieces isnot opposed thereby.

7, A magneto electric scribed.

JAMES B. FRAVLEY.

Copies of this patent may be obtained for ve cents each, by auressng the "Commissioner of Patents.

Washington, D. C.

the magnetic flux from the4 field magnets to the core pieces, said core-v machine of the type described comprising, in combination, mag-` preventing the interlink-

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