US2646543A

US2646543A - Saturable reactor voltage regulation

Info

Publication number: US2646543A
Application number: US187740A
Authority: US
Inventors: Albert D Gilchrist
Original assignee: LEECE NEVILLE CO
Current assignee: LEECE NEVILLE CO
Priority date: 1950-09-30
Filing date: 1950-09-30
Publication date: 1953-07-21
Anticipated expiration: 1970-07-21

Description

y 1953 A. D. GILCHRIST 2,646,543

SATURABLE REACTOR VOLTAGE REGULATION Filed Sept. 30, 1950 2 Sheets-Sheet l mum a M, @M QQ, W, 6%

4rrM/vs ya 7 July 21, 1953 A. D. GILCHRIST 2,646,543

SATURABLE REACTOR VOLTAGE REGULATION Filed Sept. 50, 1950 2 Sheets-Sheet 2 3 :mmm g 9 m 3 K a? Lt J0 J4 J2 if .77

Patented July 21, 1953 SATURABLE REACTOR VOLTAGE REGULATION Albert D. Gilchrist,'Lyndhurst, Ohio, 'assign'or-to The Leece-Neville Company, Cleveland, Ohio,

. a corporation'of'Ohio Application September 30, 1950, Serial No.'18'7,740

- 12 Claims. 1

This invention'relates to control apparatus for alternating current electrical generating systems and, more particularly, to improved control apparatus for alternating current generating systems of the type" used on motor vehicles for battery charging and other auxiliary purposes and in which the speed of the alternator varies withthe'speed of thevehicledriving motor.

*-In"'the higher voltage battery charging sys- -'-te'rns,such-*as for charging storage batteries of twelve to sixteen cells "or more, a troublesome problem-has always been present in regard to "obtaining along operating life for the voltage regulators of-therelay or vibratory contact type The used-with such'highe'r voltage systems. problem encountered resultsfrom the greater amountof energy required to be controlled by -the-vibratory contacts of the voltage regulator. These higher voltage systems usually require the use of a high'valueof control resistance in par- 3 allel-with the contacts of the regulator and this increases the arc intensity at the contacts and,

"hence; increases the destructive effect on the contacts. H

' In the case of voltage'regulators of the double contact type used with such higher voltage battery systems, another problem is encountered due toionization' oft-he gas present between the con- =tacts during"- transfer of the operating point of the'reg ulator from one' pair of contacts to the the other. 'Ihus'in a'situation where the voltage regulator is vibrating on the upper pair of con- .Lan'flarc. occurs between the upper pair of con- ::tacts and maintains an I ionized path therem between until the lower pair of contacts is closed, ii a' short circuit will occur through such ionized 2 math which may have a destructive efiect on the contacts. even to the extent of: causing the contacts to bewelded together" into a solid mass.

I The present invention minimizes or eliminates these difliculties and, as its principal object, provides generator system control-means inwhich the contacts of 'the' voltage .1 regulator, whether single or' multiple pairsf contacts andregard- -less of the'voltage ot the system,- are'required tocontrol onlyv airelatively small-amount of elec- 2 trical energy which will not be injurious to the contacts, andin whichsuch a relatively small amount of energyacting'through a saturable reactor included in the field excitation means of an alternator produces a strong regulating action on the'alternator.

Another'object of the'p'resent invention is to provide improved control apparatus for a generating system in which the excitation means for the alternator field includes an auxiliaryrectifier and a saturable reactor; and'in' which the mag-- netizing or control'coil" means of the reactor is controlled by regulator means of the relay type which is automatically responsiveto-the operat ing condition of the alternator and in effect acts as a voltage sensing device.

Still anotherob-jectis -to""provide improved I generator control #apparatus "of the character tacts tocontrol the voltage of the generator 7 "while the-latter isoperating under heavy load and at medium'speeds and the loadis dropped *suddenly,-'the regulator thereupontransfers its operating point to the lower pair of contacts and continues to maintain the'voltage of the genera- ,:;.tor'at:its normal value. If, at the time of-this itransfer of theoperating pointof the voltage "regulator from'one' pair of contacts to the other,

mentioned in which the regulator means consists of bothvo-ltage and currentregulators of the relay type.

A further-object is to provide improved generator control apparatus of thekind above'referred to in which the field excitation means for the alternator includes" impedance "coil means of the-reactor andwhichimpedance coil means is located in the alternating current portion of the field circuit.

Yet anotherobject is to provide'improved generator control apparatus of the character above indicated inwhich the alternator is a threephase alternator and the field excitation means for the alternator includes a three-phase rectifier and a saturable'reactor for each of the three-phase alternating current portions of the *field circuit.

- As an additional object this invention provides control apparatus of the character mentioned in which the field excitation means for the alternator includes a saturable'reactor controlled by a v voltage regulator "oftherelay typeresponsive to the operating conditioriof the alternator, and in which the energization of the magnet coil means of the voltage regulator is controlled by a'voltage divider.

This invention can" be'further briefly summarized as consisting in certain novel combinations and arrangementsof parts hereinafter described in detail and particularly set out in'the claims hereof.

r In the accompanying sheets of drawings,

Fig. 1'1s a-wiring diagramshowing generat- "ing -'system* control apparatus embodying the present invention and inwhich a saturable reactor located in the alternating current portion of the field circuit of an alternator is controlled by regulator means of the relay type responsive to the operating condition of the alternator.

Fig. 2 is a. wiring diagram showing a generating system similar to that of Fig. l but in which the voltage regulator of the regulator means is of the double contact type; and

Figs. 3 and 4 are wiring diagrams showing generating systems similar to the generating systems of Figs. 1 and 2 respectively, but in which the saturable reactor of the field excitation means is a three-phase saturable reactor.

In the embodiment of the invention illustrated in Fig. 1, a generating system I3 is shown comprising an alternator II which delivers current through a main or power rectifier I2 to an external direct current load here represented by a storage battery I3 to be charged. The alternator I I may be of the inductor type and is here shown as a three-phase alternator having star-connected inductor windings Ma, I 'ib and Hlc and a field winding I5. Th main rectifier I2 is a full wave three-phase bridge type rectifier which can be of the dry plate construction and comprises circuit arms I211, i212 and [20 with which the respective inductor windings I ia, Mb and Me are connected by conductors extending from the alternating current load terminals ita, I-Eb and H50 of the alternator. The rectifier [2 has direct current load terminals Ho and ill) to which the storage battery I3, representing the external load, is connected by the direct current load conductors I8a and [3b.

Th external direct current load circuit represented by the conductors l8a and I8b is controlled by a load relay 2!! which, in accordance with one feature of the present invention, has a novel energizing circuit which will be presently described. This load relay may be of the type comprising a magnet frame 2i including a core 22 carrying a magnet coil 23 and a movable armature 2Q in cooperating relation to such frame and core. The load relay 20 also includes normally open stationary and

movable switch contacts

25 and 26 in series relation to the load conductor Iiib of the external direct current load circuit.

The magnet windings 23 of the load relay 20 is adapted to be energized from the alternator Ii through an auxiliary rectifier 27 which is here shown as being a three-phase full wave bridge type rectifier having circuit arms 21a, 27b and 210 and a pair of direct

current load terminals

28 and 29. The terminals of the magnet coil 23 are connected with the direct

current terminals

25 and 29 by the conductors 30 and 3|. The circuit arms 27a, 23b and 210 of the auxiliary rectifier 2? are connected respectively with the terminals Ifia, Ifib and I60 of the alternator II by the

conductors

32, 33 and 34.

As an important feature of the present invention the improved generating system I includes regulating means which is automatically responsive to the operating condition of the alternator II and varies the excitation of the alternator field I so as to maintain the terminal voltage of the alternator substantially constant regardless of wide variations occurring in the speed at which the alternator is driven and in the value of the load imposed thereon. This regulating means comprises a voltage regulating unit 35 of the vibratory contact electromagnetic relay type and a current regulating unit or load limitor 36 which is also of the vibratory contact electromagnetic relay type. The field excitation means for the alternator I I includes a field circuit having therein an auxiliary rectifier 3i and a saturable core reactor 33 with which the regulator means cooperates for controlling the field excitation.

The field energizing circuit for the alternator Ii comprises a direct current portion which includes the field Winding I5 and a pair of conductors I5a and 52) connecting the ends of the field Winding with the direct current terminals iii and ll of the field rectifier 3?. The field circuit also comprises an alternating current portion connecting th alternating

current terminals

42 and 43 with one phase of the alternator II, in this instance, the phase represented by the alternator terminals I61) and IE0. For this purpose the alternating current terminal .2 of the field rectifier 3? is connected with the alternator terminal 15b by a conductor i l and the alternating current terminal 33 of the field rectifier is connected with the alternator terminal I80 through conductor means 45 and through the saturable core reactor 38 which will now be fur ther described.

The saturable core reactor 38 comprises a laminated magnet frame or core 45 which, in this instance, has three parallel magnetic circuit legs lsa, 63b and 36a. The end legs tiia and 450 carry alternating

current magnet coils

31 and 58 which are connected in series relation to each other in th alternating current portion of the field circuit by the conductor means 45. The intermediate leg 56b of the reactor 38 carries a direct current energizing or control winding 49 to which energizing current is supplied under the control of the voltage and

current regulators

35 and 33, as will be presently explained. When the control winding 49 is energized by direct current, it produces a magnetic circuit in the core 86 of the reactor 38 which opposes and controls the magnetic flux produced by the alternating

current coils

42 and 48 of the field circuit such that these alternating current coils constitute impedance coils which will, in turn, control the amount of the alternating current being supplied to the field rectifier 31 in accordance with the extent of magnetization of th reactor core 43 by the control winding 49.

The voltage regulator 35 comprises a magnet frame 5| including a core 52 having a pair of

magnet coils

53 and 54 thereon, and a movable armature 55 in cooperating relation to the frame and core. The voltage regulator 35 also includes a pair of stationary and

movable switch contacts

56 and 57, of which the latter is carried by the vibratory armatur 55. A tension spring 58 acting on the armature 55 normally urges the movable contact 51 toward a closed position in engagement with the stationary contact 56. The coil 53 of the voltage regulator 35 is a voltage coil which is connected across the load conductors I8a and I8?) by the

conductors

59 and 60 and therefore responds directly to the operating condition of the alternator I I and senses the voltage thereof. A ballast resistor 6| may be included in the energizing circuit for the manget coil 53. The magnet coil 53 is a so-called secondary coil which is in additiv relation to the voltage coil 53 and is adapted to be energized from the load conductors I8a and I8!) through a circuit which is controlled by the regulator contacts and will be presently traced.

The current regulator or load limitor 36 comprises a magnet frame 62 including a core 53 carrying a load circuit series coil 54 and a vibratory armature 65 in cooperating relation to the wmagnetnframe and core. {iThe current regulator 36 also includes stationary andmovable' switch contacts 66 and 61, of which the latter contact 'iscarried by thevibratory armature 65 and is i normally urged toward a closed'position in en-. gagement withthe' stationary contactbya tension' spring 68.

" The. voltage and current regulators 35' and-36 are automatically responsiveto the operating condition of the. alternator -ll,=. as: mentioned above, and control. the excitation of Ithafield winding 15 by controlling the :energizationof .the

control winding 49 of the saturable1'ireactor-38. In this way the-contacts of regulators 35' and 36, by controlling relatively small quantitiesxof. elec-,

vtrical energy which produce changes in the magnetizationjof thecontrol coil 49, are ableto con- 7 trol. much larger amounts-of alternating current in the

field circuit windings

41 and 48, of

thesaturable reactor and thus produce a strong regulating action; on the excitation-of the field winding 15 without'subjecting the regulator con- I tacts to harmful arcing. For thiszpurposethe and a voltage divider 10.

The voltage divider comprises a resistor 10a,

' which is connectedacross the direct current load conductors la and I8!) by the conductors H and 12, and a contact arm 19!) which is manually shiftable along the resistor 10a. The point resistor 69 has oneaend thereof connected with. .the stationary contact 66 of the current regula- 1tor 36 by a conductor 13 and has its other end connected with the armature 55, and hence the movable contact 51, ofthe voltage regulator 35 by the conductorumeans 14. Such other end of the point resistor 69 is also connected with one end ofthe magnet coil 54 of the voltage regulatorby the conductor means 15 and with one end of thecontrol winding 49 of the saturable reactor 38'.by the conductor 16. The other end of the magnet coil 54 of the voltage regulator is connected with the-arm 10bof the voltage divider 10 by a conductor 11 and the other end of the control coil 49 of the saturable reactor is also connected with themovable arm of the voltage divider through aconductor 18.

The stationary contact 56 of the voltage regulator is connected with the armature .65 of the current regulator by the conductor 19. Y The energizing circuit for the magnet coil 54 of the volt- I age regulator may also include a resistor 80 of suitable value.

In the circuit arrangement just described for coil 54 of the voltage regulator alsoincludes the point resistor 69 whenever'the switch contacts of either the voltage regulator 35 or'the'current regulator 36 are open. When the point'resistor 69 is inserted into the energizing circuit for the control winding 49 and the magnet coil 54 by the opening of the voltage regulator "or the current regulator contacts, it will produce a decreased energization of suchwinding and magnet coil to thereby decrease the magnetization of'the core '6 46 of the-saturable reactor and the magnetization of the frame 5| and thecore-52'of the-voltage regulator. The effect of this decrease inthemagnetiza- 5 tion of the core 46 ot the saturable reactorl 38 :'is to cause a decrease inthe excitation of the field winding [5 and to permit closingof the

contacts

56 and 51 ofthe voltage regulator. When I the point resistor 69 is 'short-circuited .outnof 10 this control circuit by the closing ofithecontacts of the voltage andcurrent regulators, theenergization of the control winding 49 ofathezsatur- Mable reactor 38 is increased and theienergiz'ation ofjthe. magnet coil 54 of the voltagefregulator 35 is. also increased. This increase in thei:ener- "inet' coil'54 causes. 'anxincrease in the .energization. of the .fieldwinding. I 5. and an increased .pull on thearmature 550i the voltage regulatorto cause opening of the

contacts

56 and 51 to thereby reinsert' the point resistor'69 in the control circuit. It will be understood, of course; that the opening and closing of the switch contacts of. the voltage and current regulators takes place at avery rapid vibratoryaction.

'Inithe circuit arrangements and functioning above described, the voltage divider 10 serves an important purpose because by selecting a settingfor the contact arm 10b such that the voltage applied to the regulatorcontactsfifi, 51 and 66,61 will be low,.harmful sparking or a sustained ionization at'thesecontacts willbe prevented.

Fig. 2 of the drawings shows an improvedgenthe above describedgenerating system [9 and functions in a similarmanner but in which the voltage regulator is a' double contact'regulator. Since the various parts of the system 82 are similar to the parts of the system H] and function in a similar manner, the corresponding parts have been designated by the same reference characters,with the exception of the additional pair of contacts of the voltage regulator s 35. These additional contactsof the voltage regulator are a lower pair of contacts comprising a stationary contact 83' and a movable contact'84 carried by the vibratory armature 55. The sta- 'tionary contact 83 is connected with the movable contact arm 10b of the voltage divider10 by the conductor 65. 7

Since the generating system v82 employs .circuits similar to those describedabove for the system l9, and produces an efiective regulation of the excitation of the alternator ll insubstantially the same way and with minimum destructive sparking at the contacts of the voltage and

current regulators

35 and 36, it is not-necessary to repeat the detailed description of these circuits and the functioning of the apparatus 60 -

tacts

83 and 84 of the voltage regulator 35.,addi- 'tional detailed description is needed and it is accordingly pointed out that when the condition of operation of the alternator I l is such that'the functioning'of the voltage regulator shifts'from operation on the upper pair of

contacts

56 and 51 to operation on the lower pair of

contacts

83 and 84, the closing of the lower contacts will cstablish a circuit which substantially shortcircuits the control windings 49 of the saturable reactor 38 and the magnet coil 54 of the voltage regulator and, hence, will quickly reduce the en- 'ergization of this control winding and this "regu- "'lator coil substantially to a zero value. This gizationof the control-winding 49and the:mag-' crating system 82 which is generally similar to With'respect to the lower pairof switch con- 7 circuit, established by the closing of the lower pair of

contacts

83 and 84 and which substantially short circuits the control winding 49 and the magnet coil 54, extends from the load con ductor [8a through the conductor H, then through the left-hand portion of the resistor 10a of the voltage divider 10, through the contact arm 7017, through the conductor 85, through the lower pair of

regulator contacts

83 and 84, the conductor means 14, and then through the point resistor Be and the conductor 13 to the load conductor l8b.

. By selecting a setting for the contact arm 10b of the voltage divider 'Hl such that the voltage applied to the

contacts

83, 84 of the double contact regulator 35 will be at or below the critical value for sustained ionization, the danger of burning or welding together of the contacts by the occurrence of a high short-circuiting current when the regulator operates on the lower pair of contacts is definitely prevented.

Figs. 3 and i of the drawings show other generating systems 81 and 88 which are generally similar to the systems IE] and 82, respectively, but in which the saturable reactor means of the alternator field excitation circuit is a three-phase saturable reactor. In other respects, the systems 8? and 88 employ substantially the same circuits and function in substantially the same manner as the above described systems it! and 82, and the corresponding parts and circuit connections are designated by corresponding reference characters and without repetition of the detailed description. With respect to the saturable reactor means of the generating

systems

87 and 88, it is explained that the three-phase saturable reactor 89 shown in each of these systems comprises three individual saturable reactors 89a, 89b and 890, each of which is substantially identical with the saturable reactor 38 of the generating system 40 described above. The three individual reactors 89a, 89b and 890 are located in the alternating current circuit portions of the energizing circuit for the alternator field l and one of these individual reactors is located in each of the threephase alternating current circuit portions 90, SI and 92 which connect the alternating

current terminals

53, 94 and 95 of the field rectifier 31 with the alternating current terminals lBa, lBb and IE0 of the alternator.

From the accompanying drawings and the foregoing detailed description it will now be readily understood that this invention provides generating system control means by which the field excitation of a variable speed variable load alternator can be eifectively and reliably controlled by the use of a voltage regulating device of the relay type acting through a saturable reactor located in the alternating current portion of the field energizing circuit. It will also be seen that the control exercised on the field circuit and the saturable reactor means contained therein can be produced, in part, by a voltage regulator and, in part, by a current regulator and also that, if desired, the voltage regulator can be of the double contact type and the saturable core reactor means can be a three-phase reactor. It will now also be recognized that since the regulating action of the voltage and current regulators on the field excitation of the alternator, when accomplished through the saturable reactor means, requires only relatively small voltage and current values to be imposed on the vibratory contacts of the regulators and, hence, these contacts will have a long service life. Additionally, it will be seen that this invention provides load relay energizing means for a vehicle generating system of this character in which the magnet coil of the load relay is energized directly from the alternator through an auxiliary rectifier.

Although the generating system control apparatus of this invention has been illustrated and described herein to a somewhat detailed extent, it will be understood, of course, that the invention is not to be regarded as being limited correspondingly in scope but includes all changes and modifications coming within the terms of the claims hereof.

Having thus described my invention, I claim:

1. In an electrical generating system for use on motor vehicles, an alternator having a field winding, a main rectifier, an external direct current load circuit connected with said alternator through said main rectifier, a field circuit connected with said alternator and including an auxiliary rectifier for supplying rectified curent to said field winding, a saturable reactor comprising a core having thereon a magnetizing coil and an impedance coil, said impedance coil being located in the alternating current portion of said field circuit, a voltage regulator of the relay type having magnet coil means responsive to the operation of said alternator and also having vibratory switch contact means, a circuit for energization of said magnet coil means and said magnetizing coil from said direct current load circuit and controlled by said contact means, and a voltage divider in the last-mentioned circuit for selecting the voltage of the current supplied to said magnet coil means.

2. In an electrical generating system for use on motor vehicles, an alternator having a field winding, a main rectifier, an external direct current load circuit connected with said alternator through said main rectifier, a field circuit connected with said alternator and including an auxiliary rectifier for supplying rectified current to said field winding, a saturable reactor comprising a core having thereon a magnetizing coil and an impedance coil, said impedance coil being located in the alternating current portion of said field circuit, a voltage regulator of the relay type having magnet coil means responsive to the operation of said alternator and also having vibratory switch contact means and a resistor in shunt relation to said contact means, a circuit for energization of said magnet coil means and said magnetizing coil from said direct current load circuit and controlled by said contact means and said resistor, and a voltage divider in the last-mentioned circuit adapted to permit the selection of a relatively low value for the voltage applied to said contact means.

3. In an electrical enerating system for use on motor vehicles, an alternator having a field winding, a main rectifier, an external direct current load circuit connected with said alternator through said main rectifier, a field circuit connected with said alternator and including an auxiliary rectifier for supplying rectified current to said field winding, a saturable reactor comprising a core having thereon a magnetizing coil and an impedance coil, said impedance coil being located in the alternating current portion of said field circuit, a voltage regulator of the relay type having a first magnet coil connected across said direct current load circuit and a second magnet coil and also having vibratory switch contact means, and a circuit for ener-gization of said magnetizing coil and said second magnet coil from said direct current load circuit and controlled by said contact means. 4.'In"an electrical generating :system for use on motor vehicles, an alternator having a field winding, a main rectifier, an external direct current load circuit connected with said alternator through said main rectifier, a field circuit condirect current load circuit and a secondm-agnet coil and also having vibratory switch contact means, a circuit for energization of said magnetizing coil and said second "magnet coil from said direct current load circuit and controlled by said contact means, and a voltage divider in the last-mentioned circuit for varying the voltage of 1 the current supplied to said magnetizing coil and to said second magnet coil and also adapted to permit the selection of a relatively low value for the voltage applied to said contact means.

5. In an electrical generating system for use on motor vehicles, an 'alternatorhaving a field winding, a main rectifier, an external direct ourrent load circuit connected with said alternator through said main rectifier, a field circuit connected with said alternator and including an 1 auxiliary rectifier for-supplying rectified-current to said field winding, a saturable reactor com,- prising a corehaving thereon a magnetizing coil and 'an'irnpe'dance coil,said impedance coil being located in the alternating current portion of said field circuit, a voltage regulator of the relay type.

having voltage magnet coil means connected across said direct current load circuit and responrent load circuit and controlled by the switch contact means of said voltage regulator and by the switch contact means of said current regulator, and a voltage divider in the last-mentioned circuit for varying'the voltage of the current supplied-to said magnet coilmeans and also adapted to permit the selection of a relatively low value for the voltage applied to said contactmeans.

"7. In an electrical generating system for use on .motor vehicles, an alternator having a field winding and load terminals, a main rectifier, an

.external :direct current load circuit connected with said load terminals through said main rectifier, a load relay having a magnet coil and series -switch contacts controlling said load-circuit, said switch contacts being normally open and adapted to be closed by energization of said magnet coil, regulating means including relay means energized from said load circuit and operably connected with said field Winding for varying the energization of the latter automatically in response'to changes in the operating conditions of said alternator, an auxiliary rectifier, and circuit means connecting said magnet coil with said load terminals through said auxiliary rectifier for i causing such energization of said magnet coil and closing of said series switch contacts in response to operation of the alternator.

8. In an electrical generating system for use on motor vehicles, a three-phase alternator having a field winding and load terminals, a full wave three-phase main rectifier, an external direct current load circuit connected with said load terminals through said main rectifier, a load relay having a magnet coil and series switch contacts controlling said load circuit, said switch contacts being normally open and adapted to be sive to the operation of said alternator, said voltage :reg ulator also comprising switch contact means adapted to be vibrated by said voltage magnet coil means, a current regulator of the relay type having a current magnet coil in said direct current load circuit and responsive to the operation of said alternator and switch contact means adapted to be vibrated by said current magnet coil, and a circuit for energizing said magnetizing coil from said direct current load circuit and controlled by the switch contact means of said voltage regulator and the switch contact means of said current regulator.

6. In an electrical generating system for use on motor vehicles, an alternator having a field winding, a main rectifier, an external direct current load circuit connected with said alternator through said main rectifier, a field circuit connected with said alternator and including an auxiliary rectifier for supplying rectified current to said field winding, a saturable reactor comprising a core having thereon a magnetizing coil and an impedance coil, said impedance coil being located in the alternating current portion of said field circuit, a voltage regulator of the relay type having magnet coil means responsive to the operation of said alternator and switch contact means adapted to be vibrated by said magnet coil means, a current regulator of the relay type having a current magnet coil in said load circuit and responsive to the operation of said alternator and switch contact means adapted to be vibrated by said current magnet coil, a circuit for energizing said magnet coil means of said voltage regulator and said magnetizing coil from said direct curclosed by energization of said magnet coil, regulating means including relay means energized from said load circuit and operably connected with said field winding for varying the energization of the latter automatically in response to changes in the operating conditions of said alternator, a full Wave three-phase auxiliary rectifier, and circuit means connecting said magnet coil with said load terminals through said auxiliary rectifier for causing such energization of said magnet coil and closing of said series switch contacts in response to operation of the alternator.

9. In an electrical generating system for use on motor vehicles, an alternator having a field winding, a main rectifier, an external direct current load circuit connected with said alternator through said main rectifier, a field circuit connected with said alternator and including an auxiliary rectifier for supplying rectified current to said field winding, a saturable reactor comprising a core having thereon a magnetizing coil means and an impedance coil means, said impedance coil means being located in the alternating current portion of said field circuit, a first control circuit for energizing said magnetizing coil means, a second control circuit adapted to substantially short-circuit said magnetizing coil means, and a voltage regulator of the relay type having voltage magnet coil means connected across said direct current load circuit and responsive to the operation of said alternator, said voltage regulator also comprising vibratory contact means including one pair of contacts controlling said first control circuit and a second pair of contacts controlling said second control circuit.

10. In an electrical generating system for use on motor vehicles, an alternator having a field winding, a main rectifier, an external direct oursubstantially short-circuit said magnetizing coil 1 means, a voltage regulator of the relay type having voltage magnet coil means responsive to the operation of said alternator and vibratory contact means including one pair of contacts controlling said first control circuit and a second pair of contacts controlling said second control circuit, and a voltage divider connecting said control circuits with said direct current load circuit and adapted to permit the selection of a relatively low value for the voltage applied to the contact means of said voltage regulator.

11. In an electrical generating system for use on motor vehicles, a polyphase alternator having a field winding, a main rectifier, an external direct current load circuit connected with said alternator through said main rectifier, a field circuit connected with said alternator and including an auxiliary rectifier for supplying rectified current to said field winding, saturable reactors corresponding in number with the phases of said alternator and each such reactor comprising core means having magnetizing and impedance coils thereon, said impedance coils being located in the alternating current portion of said field circuit and connected with the respective phase terminals of said alternator, a first control circuit for energizing said magnetizing coils, a second control circuit adapted to substantially shortcircuit said magnetizing coils, and a voltage regulator of the relay type having voltage magnet coil means connected across said direct current load circuit and responsive to the operation or" said alternator, said voltage regulator also comprising vibratory contact means including one pair of contacts controlling said first control circuit and a second pair of contacts controlling said second control circuit.

12. In an electrical generating system for use on motor vehicles, a polyphase alternator having a field winding, a main rectifier, an external direct current load circuit connected with said alternator through said main rectifier, a field circuit connected with said alternator and including an auxiliary rectifier for supplying rectified current to said field winding, saturable reactors corresponding in number with the phases of said alternator and each such reactor comprising core means having magnetizing and impedance coils thereon, said impedance coils being located in the alternating current portion of said field circuit and connected with the respective phase terminals of said alternator, a first control circuit for energizing said magnetizing coils, a second control circuit adapted to substantially short-circuit said magnetizing coils, a voltage regulator or" the relay type having voltage magnet coil means connected across said direct current load circuit and responsive to the operation of said alternator, said voltage regulator also comprising vibratory contact means including one pair of contacts controlling said first control circuit and a second pair of contacts controlling said second control circuit, and a voltage divider connecting said control circuits with said direct current load circuit and adapted to permit the selection of a relatively low value for the voltage applied to the contact means of said voltage regulator.

ALBERT D. GILCHRIST.

References Cited in the file of this patent UNITED STATES PATENTS Niunber Name Date 1,710,755 West Apr. 30, 1929 1,788,222 Winter Jan. 6, 1939 2,161,179 Logan June 6, 1939 2,374,012 Hanna Apr. 17, 1945