US1098452A - Inductor-magneto alternator. - Google Patents

Description

I J. LE PONTOIS.

INDUGTOR MAGNETO ALTERNATOR.

APPLICATION FILED JULY 11I 1908. 1 098 452, Patented June 2, 1914.

3 SHEETS-SHEET 1.

lnvenioz? .fliiorneya.

L. J. LE PONTOIS;

INDUGTOR MAGNBTO ALTERNATOR.

APPLICATION FILED JULY 11, 1908.

3 SHEET3-BHEET 2.

L. J. LE PONTQIS.

INDUGTOR MAGNBTO ALTERNATOR. APPLIOATION FILED JULY 11,1908.

1,098,452, Patented June .2, 1914.

3 8EEETSSHEET 3.

LEON J. LE PONTOIS,

OF NEW ROCHELLE, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, TO H. W. JOHNS.

INDUCTOR-MAGNETO ALTERNATOR.

Specification of Letters Patent.

Patented J une 2, 1914.

Application filed July 11, 1908. Serial No. 443,023.

To all whom it may concern:

Be it known that I, LEON J. Ln Powrors, a citizen of the Republic of France, residing at New Rochelle, in the county of VVestchester and State of New York, have invented certain new and useful Improvements in Inductor-Magneto Alternators, of which the following is a full, clear, and ex act specification.

My invention relates to alternating current machines and more particularly to an alternator of the magneto inductor type, and although especially well adapted for the production of an ignition spark for gas engines, yet my improvements may be utilized in other forms of apparatus.

One objection to magneto generators resides in the fact that in order to produce magneto generators in which the strength of the magnetic field will be maintained for a suitable length of time and in which the magnetic leakage will not be excessive, it is necessary that the length of the permanently magnetized portions of the magnetic circuit. be comparatively great. With such magnets and with proper attention to design, an efiicient magneto and one in which the permanency of the magnetic circuit will be maintained can be produced. In some classes of work, however, the comparatively large size of the machine is objectionable and, of course, involves greater expense in construction. In motor vehicles driven by gas engines, it is particularly important that the size of the magneto generator be small.

By my invention I have succeeded in producing a magneto inductor generator very small in size and particularly well adapted for use on motor vehicles having the power supplied by gas engines.

My invention will be understood from the following description and accompanying drawings, in which Figure 1 is a vertical cross sectional view of one form of machine embodying my invention; Fig. 2 is a longitudinal cross section thereof; Fig. 3 is a sectional view on the line 3-3 of Fig. 2; Fig. t is an end view of the machine; Fig. 5 is a diagram of electrical connections; Flg. 6 is a wave diagram; Fig. 7 is a modified-diagram of electrical connections; Fig. 8 is a diagram of electrical connections of a modified form of my invention; Fig. 9 is an end view of a machine arranged for making the connections described in connection with Fig. 8; and Flg. 10 is a detailed View of the cam arranged to secure the change of connections described in connection with Fig. 8.

Referring to the structure of the machine shown in Figs. 1 to 4, the same comprises pedestals 1., 1 for supporting the machine as a whole and having bearings for permitting the angular adjustment of the external element of the machine to any fixed position desired for adjusting the time of maximum current generation. The external field element is circular in general outline and is built up of laminae 2 of the form shown in Fig. 1. Each lamina of iron or steel comprises permanently magnetized hardened portions 3, 3 having integral therewith the soft iron polar extensions N, N and S, S as Well as soft iron connecting bridges a, 4. The soft iron polar extensions and connecting bridges may sometimes be otherwise secured to the permanently magnetized portions 3, 3 of hardened iron, but I prefer to form all of these parts in an integral lamina or plate, as indicated in the drawings. Each of the plates 2 may bemagnetized by placing the surfaces of the two opposing central portions in close proximity respectively to the north and south poles of a powerful magnet which will complete its magnetic circuit through the portions 3,3 and develop two consequent poles of opposite polarity in the central opposing portions. The extensions N, N will therefore assume one polarity, say north, while the extensions S, S of the opposite central portion will assume the opposite or south polarity. I have obtained the best results by placing the plates 2 in close proximity to the magnetizing electromagnet as above referred to while the plates are at a high temperature of 715 degrees C. The portions 3, 3 which are to be permanently r agnetized are then suddenly cooled and hardened while under the influence of the magnetic field. The central port-ions comprising the polar extensions and the connecting bridges 4," l" remain annealed and when the plate is removed from the influence of the electromagnet, the central portions are magnetized only by the inductive action of the permanently magnetized portions 3, 3. 3y thus providing an integral plate which is hardened and pern'ianc-ntly magnetized in certain portions while having soft iron portions of high permeability, I obtain magnetic circuits of minimum reluctance, and also secure great strength and rigidity in the magnetic structure. It will be noted that the form of the field structure secures a Very compact arrangement, giving small size tothe machine and although the permanently magnetized portions have magnetic circuits of short length and therefore not so well adapted for maintaining their strength and permanency, yet I proride means for assisting the magnets in maintaining a high field strength and thus C0l1li 3n$tlt0 for the comparatively short length of the permanently in agnetized parts.

The plates 1., after being built up to form the field frame, are clamped together in any suitable manner as by through bolts 5, and siuported as a whole by end plates 6 which are rotatably mounted in the pedestals l, Wound around the bridge portions 4, 4: are the gmieratiug coils 7, 7. A few of the huninv at the ends of the field frame have the portions .1:, it removed in order that the generating windings 7. 7 will not extend beyond the ironportion of the field frame, the inner surface at one end of the cgil 7 being indicated by a dotted line in Fig. 2. Surrounding the polar extensions N, N is placed an exciting coil 8, and around the polar extensions S, S is placed a similar exciting coil S. By reason of the end portions of the coils T, 7 not extending beyond the iron frame these coils will be inclosed by the coils 8, S 'and thus avoid undue increase in length of the machine, although of course, this construction may be departed from where small size of the machine is not such an important factor. Between the end plates 6 and the laminae 2 are inserted spacing portions 9 of little greater width than the end portions of the coils 8, 8. Around the field frame is a non-magnetic sheathing 10 for protection of the parts. One of the end plates is provided with an extending part .11 to which an operating rod may be connected for the purpose of conveniently adjusting the angular position of the field frame as a whole for advancing or retarding the time of maximum current generation. Within the extensions 6 are formed roller bearings for supporting the shaft 12 of the inductor 13, part of the inductor and shaft 12 being broken away in Fig. 2 for the purpose of showing the structiire of the field element to better advantage. The inductor13 is shown in cross section in Fig. 1, and I prefer to make the distance between the tips of the poles N and S and between N and S somewhat less than the distance between the poles N and N and between S and S, as indicated in Fig. 1, for the reason hereafter explained.

The inductor or rotor 13 will be driven by the gas engine whose sparking is to be controlled, and in the'present instance the ratio of the speeds will be 1 to 1, or, in other words, for each revolution of the engine, the inductor 13 will also make one revolution. ()n the shaft 12 is mounted a cam 14 for controlling the production of the spark in the engine cylinders. A roller 15 engages the cam and a spring 16 tends to maintain the roller 15 in engagement with the cam. The roller is carried by a lever 17 mounted upon a shaft 18 which is mounted in and extends through a partition 19 secured to the stationary element of the machine, which partition. also protects the make and break contacts from the oil of the-bearings. The shaft 18 carries upon its outer end an extension 20 which in turn carries a movable contact 21. and the latter is adapted to make and break connection with afixed contact 22.

The electrical connections and circuits are shown in Fig. The two generating coils 7, 7 are shown connected in parallel with each other and in series with the two exciting coils 8, S which latter are connectedi'in parallel with each other. Electrical connection is made from terminals of the generating windings to one terminal of a primary winding 23 of a transformer, the remaining terminal. of winding 23 being connected to the exciting coils 8, 8. In parallel with the generating and exciting coils and with the primary winding 23 is connected a. suitable condenser 24. The make and break device already described is conneeted so that the movable contact '21 is connected to one side of the circuit and the fixed contact 22 is connected to the other side of the circuit; thus when the terminals 21, 22 are in contact, a short circuit is made'between the two sides of the main circuit and in this manner closes a circuit containing the generating and exciting coils in one loop. as well as short circuiting the terminal of the condenser and primary winding 23. The secondar winding 3 of the transformer i shown connected in series with a spark plug 25 of the usual type and it will be understood that the usual distributer will be connected in the secondary transformer circuit for controlling the connections to the spark plugs in the different engine cylii'iders. The distributor and various spark plug circuits are not illustrated however as their operation is well understood.

In order to explain the operation of the machine, we may consider the wave indicated in Fig. (3, and although the electrometive force actually produced will be of irregular form. yet the general form of wave indicated in Fig. 6 will sufhce for the purposes of explanation, the solid portions of the curve representing positive electromotive force values, and the dotted portions negative values.

When the inductor 13 is in the general position a, a, the magnetic flux through the inductor will be a maximum. The path of the magnetic flux in this position through the generating windings will be in one circuit from pole N' through the inductor to pole S, through the yoke portion 3, then through the bridge connection 4 and coil 7 to pole 1*. In another path the flux will pass from pole N through the inductor to pole S, thence through the bridge connection t and coil 7, and then through the yoke portion 3 to pole N. The magnetic flux through the generatin coils will then be a maximum and as at t is time the rate of flux change is zero, the electromotive force will be substantially zero as indicated at'a in Fig. 6. The coils 7, 7 are connected in parallel so that their electromotive forces Will act in the same direction in the electric circuit, although if desired the coils may be connected in series with each other. As the inductor passes from the position a, a, assuming right hand rotation, the reluctance of the magnetic circuit will be increased by reason of the inductor passing from under the poles N and S. This increase in reluctance causes decrease of flux through the generating coils in the paths previously traced and thereby causes increase in electromotive force generated, so that when the inductor is in position b, b, the rate of change in flux is a maximum approximately and this results in the generation of maximum electromotive force as indicated at b, in Fig. 6. As the rotor approaches position 0, c, the rate of change of flux decreases until in position a the flux through the generating windings in the opposite direction becomes a maximum and the rate of change is practically Zero, giving in this position 0 practically-no electromotive force, as indicated at c in Fig. 6. The paths of the magnetic flux in the position 0, c, of the inductor will be as follows: One path from pole N through the inductor to pole S, thence through the yoke 3 passing through the bridge 4, and coil 7 back to pole N, and in another path from pole N through the inductor to pole S, through bridge 4: and coil 7, thence through the yoke 3 to pole N. As the inductor passes from position 0, 0, the flux through the generating windings will begin to decrease causing eloctromotive force to be generated therein in the opposite direction and at position (5, cl approximately. the rate of change of flux is a maximum giving maximum electromotive force in the opposite direction as indicated at (Z of Fig. 6. As the inductor approaches position a, a, the magnetic flux increases in the opposite direction through the generating coils and in position a, or, approximately the rate of change is zero although the flux through the windings is a maximum giving zero electromotive force approximately, as indicated at a in Fig. 6. The path of the magnetic flux will then be the same as previously traced when the inductor was in p0 sition a, a, reversed. As the inductor continues its revolution from-the position a, a to positions 6, Z), c, 0, (Z, (Z and back to a, a, the cycle of electromotive force generation will he understood as being indicated in positions b, c, d and a, respectively. It will therefore be seen that in one complete revolution of the inductor, the electromotive force generated will correspond in a general way to that indicated in Fig. 6, giving two positive and two negative waves. It will be understood that the above description of changes is very general without considering the various factors that modify the form of the wave or the action at different positions and is described for the purpose of indicating in a general way what occurs during one complete revolution of the inductor.

One important factor which modifies the action above referred to is the induction of the circuits and such induction will, of course, cause the current which flows to lag behind the induced electromotive force. Consequently, the maximum current strengths will not occur when the inductor is in positions 7), b and (i, (Z, but will occur after the inductor has advanced beyond these positions. As the engine is geared to the magneto in the ratio of 1 to 1 and as in the present instance an engine requiring two explosions per revolution is contemplated, two sparks should be produced per revolution of the magneto and these of course should occur when the current is a maximum. The form of the caml l is such that the contacts 21, 22 will be separated twice per revolution when the current is a maximum and flowing in say positive direction and will remain separated until the current has decreased to zero and reversed and decreased to zero agaln. The contacts Wlll be' closed during increase in current to maximum value in a positive direction. The cam 14. is therefore provided with two diametrically opposite raised portions 14c, which will operate to raise the roller 15 and separatcthe contacts of the breaker during the periods above mentioned and permit the breaker to be closed during the other periods.

The connections of exciting coils 8, 8' are such that when the two positive waves -for example are generated, the direction of current through the exciting coils will tend to maintain and build up the strength of the magnetic field. Considering the action more in detail. it will be understood that during the generation of the increasing portion of the positive waves, the direction of current in the generating coils 7, 7 will. be such as to also tend to build up and strengthen the magnetic field. During the decreasing portion of the positive waves, the current in the generating windings will oppose the magnetic flux in the new paths and therefore tend to demagnetize and weaken the field element. This demagnetizing action of the generating windings will be counter-acted 1 by the current in the exciting coils which,

of course, continues to maintain the mag netic field strength during the generation of the positive waves. During the generation of the negative waves the increasing negative currents in the generating Windings will tend to maintain the magnetic field but will tend to demagnetize the field during the decreasing portion of the negative waves. The current flowing in the exciting coils during the generation of the negative waves, will, of course, tend to demagnetize the field element, but the demagnetizing effect will be very much less than the magnetizing effect. In the first place the demagnetizing action of the exciting coils occurs at a time when the energy is not being utilized and its effect during the generation of negative waves is therefore comparatively unimportant in View of the magnetizing effect which afterward occurs during positive wave generation when the energy is utilized in the spark discharges. Again during the generation of negative Waves, the circuit breaker being open, the generating coils, exciting coils and primary winding 23 will be connected in series with each other, giving maximum impedance in the circuit, which will of course, tend to cause the negative current to have less value than the positive current when the circuit breaker is closed. Also by reason of the space between-the tips of the poles N, S, and between the tips of the poles N, and S being less than the space between the poles N and N and between the poles S and S, there will be greater leakage during the generation of the negative waves which will also tend to decrease the value thereof com-- pared with the value of the positive waves. The effect of the various actions is such as to maintain the magnetic field strength indefinitely even though alternating current waves are passed through the circuit of the exciting coils and even though the permanently magnetized field element is of comparatively small size with short magnetic circuits. Also at the time the energy is utilized, the generation is such as to give heavy spark discharges.

In Fig. 7, another form of connections is illustrated, the condenser 24 being connected in series in the circuit instead of in parallel as in Fig. 5, and the breaker when closed is adapted to short circuit the conillustrates another modification. The exciting coils 8, 8 instead of being permanently connected in series with the generating coils 7, 7 are adapted to be cut in and out of circuit by the operation of the breaker. The flexible arm 20 of the breaker instead of making one contact as in the forms pre' viously considered, is adapted to engage the fixed contact 30 in one position, thereby closing a circuit through the generating coils and excitin coils, and in another position is adapted to engage the contact 31 thereby removing the exciting coils from circuitand short circuiting the generating coils; when the circuit breaker is in open position, the spark will be produced. The form of the cam 32 used in this construction will be as shown in Fig. 10. The relation of the cam to the roller 15 controlled thereby, will be such that during the period of increasing current in say the positive direction, the generating windings will be closed 011 themselves, and when the current attains or approaches a maximum in this direction, the breaker will be opened by the cam for causing the spark discharge.

hen the negative current is afterward generated, the cam will cause the breaker to be closed through the generating coils and exciting coils, the connection of the exciting coils being such that the negative current which fiows will tend to magnetize and strengthen the field element. When the current again changes direction and begins to increase in a positive direction, the breaker will cause the exciting coils to be disconnected from circuit and then close the generating coils on themselves, after which the breaker will be opened for causing the spark discharge, and finally the breaker will close the circuit through the exciting coils again when the direction of current is reversed. This will complete the cycle per revolution of the machine and the same sequence 0 connections will afterward be repeated. Referring to the cam shown in Fig. 10, when the roller bears on line 33 the flexible arm 20 is forced in such direct-ion as to'cause engagement with contact 31 closing the circuit of the generating windings on themselves, and this condition of connections will continue during the period of increasing positive current. When the cam is turned so that the roller bears on line 84, the circuit through contact 31 will be broken, causing the spark, discharge, and the breaker will remain open until the roller bears on line 35 when the circuit through contact 30 will be closed. This, as above referred to, will closethe circuit of the generating coils through the exciting'coils' and this condition will continue duringthe flow of the negative current approximately. When the, roller bears online 33', the conditions will be the same as when the roller was on line 33 and it. will be-noted that there is an abrupt change on the cam above line 33 so as to cause the arm 20 to be rapidly thrown from contact 30 to contact 31. As the roller passes over the remaining half of the cam,

the sequence of connections obtained will be the-same as above referred to.

It will be understood that various other modifications-may be devised and various changes made in design without departing from the scope of my invention.

Having thus described my invention, I declare that what I claim as new and desire to secure by Letters Patent, is,-

1. In an inductor alternator, a generating winding embracinga portion of the magnetic circuit which is subjected to the maximum change in magnetic flux, an exciting winding supplied with alternating current from the generating winding and embracing a portion of the field element which is subjected to less change in magnetic flux,

and circuit changing means for causing the current wave through said exciting winding in one direction to be more efiective for exciting the field element than the current wave in the opposite direction.

2. In an alternating current generator, a generating winding embracing a portion of the magnetic circuit which is subjected to the maximum change in magnetic flux, an exciting winding supplied with alternating current derived from said generating winding for strengthening the field element and embracing a portion of the field element which is'subjected to less change in ma netic flux, and means connecting said win ings in series with each other.

3. The combination of a permanently. magnetized field element, an inductor, a

generating winding on the field element, and an exciting winding on the field element supplied withalternating. current from saidgenerating winding.

4. A dynamo electric generator'for supplying energy to a sparking device, comprising a plurality of generating windings on the field element, a plurality of ex-, citing field windings on the field element supplied with alternating current from said generating windings, and means for varying the flux through said generating windings.

5. In an inductor alternator, a generating winding, and an exciting winding for the field element supplied with alternating current from the generating winding, the field element having unequally spaced parts projecting toward the rotor for causing the current wave in one direction to be more effective for exciting the field element than the current wave in'the opposite direction.

6. A generator having a stationaryanda rotating element, an alternating current generating winding onthe field element embracing a ortion of the magnetic circuit which is sub ected to-the maximum change in magnetic flux, and a field winding on the field element embracing a portion of the magnetic circuit which is subjected to less change in magnetic flux, said generating winding and said field winding being connected to each other to cause said field winding to be supplied from said generating winding with current of the same character as generated in said generating winding.

7. The combination of a generator'havingan alternating current generating winding for supplying a sparking discharge current when the alternating current therein is a maximum value in one direction, afield winding, and circuit'changin means and connections for causing said eld winding to be supplied with current from said generating' windin when the current flow-s in said-one directlon and for causing a lesser current. to be supplied to said field winding when the current flows in the opposite direction, said circuit changing means being controlled by said generator and forming a' unitary structure therewith.

8. The combination of a generator having a stationary element,-ar rotating element, a plurality of alternating currentgenerating windings rality of exciting windings located onthe same element as said generating-winding and supplied with' current from said generating windings, :and circuit changing means for causing the current assing through said exciting windings to ave a higher value when the current flows in the direction in whichv magnetization of said. same element is effected.

9. The combination of a generator having a. stationary element and a rotating element, an alternating current generating winding for supplying a sparking discharge current, an exciting winding supplied with current from said generating w1nding,both of said windings being located on the stationary element, andthe field element having unequallyspaced parts projecting toward-the rotating element for causin the current wave energized in one direction to efiect a greater excitation of the field element than on one of said elements, a plusions, anda rotor for reversing the mag,

netic fiux through said generating windings. 12. The combination of afield element built up of a plurality of plates, eachof said plates comprising a permanently mag-p netized hardened portionand soft iron portions integral therewith, a generating 'winding, and an exciting winding for increasing;

I the strength of said field element.

13. The combination of .a field element comprising a plurality of permanently magnetized portions and a plurality of soft iron polar extensions, a generating-winding on said fieldelement, and an exciting winding for said field element supplied with current from said generating winding,and a rotor;

for reversing the magneticnflux through said generating winding.

14. In a magneto generator of the inductor type, the combinationyof a stationary frame comprising an integral member, said member having two permanently magnetized portions of hardened iron and portions of soft iron connecting poles. of like polarity and integral with-said magnetized portions,

windings on said soft iron portions, an exciting winding for increasing the magnetic strength of said frame supplied with energy from said first named windings, and a rotor for controlling the paths ofthe magnetic flux.-

15. In a magneto generator of the inductor type, the combination of a permanently magnetized field frame having a plurality of soft iron polar projections, a generatingv winding on said frame, an exciting winding for strengthening the magnetic field, supplied with current fromsaid generating winding, andv a rotortfor controlling the paths of the magnetic fiux..

16. In a magneto generator, thecombi-nation of an element comprising a permanently magnetized portion of hardened iron and 7 soft iron polar portions, a secondv element for controlling the paths of the mag.- netic flux, a generating winding on one .of said elements, and an exciting windingon saidfirst named element supplied with cur rent from said generating winding,.and of the. same character as flows insaid generating winding, for increasingthe magnetism of said element.

17. In a magneto generator of'the inductor type, the combination-of a frame having permanently magnetized portions. of bar dened iron, portions of soft -1IOI1' connecting poles of like polarityand having, polar extensions, generating windings on said soft iron portions, a rotor vfor controlling the paths of the magnetic flux, and an exciting winding inclosing said polar extensions of 7 said element supplied with current from said first named winding;

18. In an alternating current generator, the combination of a permanently magnete ized field element, a generating winding, an. exciting Winding for strengthening thev magnetism of the field element, said exciting winding being electrically connected with and supplied withpcurrent from said generating winding, and circuit controlling means for causing the current passing through sald excltmg winding to have a higher value when the current: flows in one direction than when the current flows in the opposite direction.

19. The combination of a field-element having. apolar extension and-comprising two permanently magnetized 3 ortions having soft iron portions connecting like poles of said permanently magnetized portions, generating windings on said connecting portions, a rotor for reversing the magnetic flux through said-windings, and an exciting coil supplied withcurrent' from at least one of said windings inclosingsaidpolar extent sion of said element.

In testlmony whereof I afiix my-signa-' ture, in presence of twowitnesses.

LEON J. LE PONTOIS. Witnesses:

BENJAMIN Hum),

L. K. SAGE.

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