US1475880A - Controlling and regulating system for dynamos - Google Patents

Description

Nov. 27 1923. 1,475,880

w. J. RICKETS CONTROLLING AND REGULATING SYSTEM FOR DYNAMOS Filed May 21, 1920 WITNESSES INVENTOR J v WZZIWI/n JjQz'cZfe Zs. M .7 Br Q 6 M w ATTORNEYS Patented Nov. 27,1923.

UNITED STATES- WILLIAM JOHN RICKETS, OF LONDON, ENGLANI).

CONTROLLING AND BEGULATING SYSTEM FOR DYNAMOS.

Application filed Kay 21,

To all whom it out concern:

Be it known t at 1, WILLIAM JOHN Flowers, 21 subject of the King of Great Britain, and a resident of London, England, have invented a new and Improved Con trolling and Regulating System for Dynamos, of which the following is a full, clear, and exact description.

This invention relates to improvements in regulating systems of the kind described in my %IEV1OUS British provisional specification 0. 11,123 of 1919, hereinafter referred to as the former specification.

In this specification electronic or ionized gas valves of the incandescent cathode type are described as being employed as controlling means .for' use with variable speed dynamos, for regulating the voltage and the charging or output current of such dynamos.

In the practical use of such devices certain difficulties and limitations manifest themselves, and it is the object of the present invention to improve the arrangements described in my former specifications in such manner as to render the apparatus more eilicient in action, and of wider applicability.

In the previous arrangements referred to the cathodic filament or filaments are rendered incandescent by current taken through a resistance or a; field winding from the main brushes of the dynamo.

If exact regulation is to be obtained the heating of the filament should be due,predominantly, to this current and not to that flowing from the anode of the valve.

' Hence the current flowing from the anode should alwa s be less than that directly supplied to t e filament which condition imposes certain limits of design.

hA ain when the valve is used to regulate t e accumulator battery, this current is a so lim ited by the carrying capacity of the cathodic filament.

If this filament is increased in cross-section, to carry more current, and is heated by the main field current, or by current passing through a resistance and flowing under the full output volts, the loss in such a resistance or in the main field winding becomes great for a large current carrying capacity of valve, and the efficiency of the whole system is lowered.

According to the present invention heating of the filamental cathode of the valve is effected by current generated in a closed ow of charging current passin to an 1920. Serial No. 383,194.

loop circuit including the filament, one point of which circuit is connected to the negative pole or brush of the generator.

This loop circuit may be of low'resistance and the filament may have large currentcarrying capacity whilst requiring a relatively small wattage for heating.

As the filaments so proportioned and disposed can be of considerable crow-section and therefore will not be liable to become excessively heated by anodic current they are especially useful in controlling the battery current in the manner set forth in my other application above referred, to, by the use of a bi-anodal valve or two valves and the resistance system as shown in Figure 4 of that specification. I

The voltage actin in the loop circuit is so produced that it is, at all times, a function of the field strength and speed'o'f the machine.

The incandescence of the filament therefor varies with the output voltage and hence regulation of this voltage is obtained in the manner set forth in the said specification.

For the better explanation of the invention reference is made to the appended drawin Fi ures l to 8.

Of t ese igures 1 and 2 represent the application of the valve tube as a regulator for a'dynamo.

Figure 3 is a modification of Figure 1 of this specification illustrating means by which voltage regulation of large generators can be conveniently obtained with small excitation losses.

Figures 4, 5, and 6 represent diagrammath cally alternative methods of heating the filaments.

Figure 7 represents another arrangement for using a valve as regulator in the manner set forth.

Fi re 8 relates to the disposition of a switc for allowing reversed rotation of the machine.

Referrin to Figure 1 of the present specification a irect current ring, drum or like armature 1 having brushes 2 and 3 is con nected with a shunt field winding 5 and a differential winding 13.

The winding 5 may be connected to the two brushes directly or, as shown, through the cathodic filament 6 of the valve 7.

The armature 1 is provided with a winding of-known type generating continuous current and also has an electrically indeltl pendent 'windin generating alternating current connecte to the slip rings 8 and 9 amociated with brushes 10 and 11 connected to the filament 6, the whole circuit constituting a closed loop which is connected to the negative pole or brush 2.

The anodic late, sheath or like electrode 12 is connected to the winding 13 which is magnetically opposed to the shunt field winding 5..

The eperationof the system thus arranged is as follows:

The direct current voltage generated in armature windin 1 always bears a definite ratio to the effective alternating voltage applied to the filament 6.

Hence as a certain predetermined voltage is approached the filament 6 becomes incandescent and the consequent increase in the valve conductivity allows current to fiow through the counterwinding 13 limiting the possible voltage rise of thesystem. o

The negative pole of the battery may be connected to the anode 16 by means of the switch arm 18, which in this case will rest on a contact 19. As arranged in Figure 1, part or the counter winding functions as a series winding, employing the dynamo as a motor for starting any mechanically connected prime mover or alternatively a separate series winding may be employed for the purpose in which case the connections will be as shown in dotted lines.

By these arrangements the battery is nrmally prevented from discharging through the armature circuit, but when the cathode filament becomes incandescent at the appropriate voltage, the dynamo will charge the battery over the following circuit: terminal. 3 of the dynamo, winding 18, wire 23, bat tery l4, switch arm 18 contact 19, over the wire to anode l6, filament 6 and thence to terminal 2 of the dynamo.

Leads 23 and 24: as shown in the figures carry the output current to consuming circuits.

Figure 2 shows a second method of connecting the shunt winding in which this winding is in series with ballast resistance 25, the junction of this resistance and field winding being connected to the anode 12 of valve 7 in which a second battery charging anode 16 may be arranged be fore.

This arrangement functions by diverting current from the field winding, when the valve conductivity increases, thus reducing the excitation as the predetermined voltage is approached.

Figure illustrates a method whereby the voltages of dynamos of large Output may be positively and practically limited with small excitation losses.

This arrangement comprises the larger capacity output generator A and a smaller lat/asst capacity counterboosting generator B, these generators being mechanically coupled together.

The main generator armature has a separate alternating current winding and slip rings 8 and 9.

The slip rings are connected as in Figure l to a valve cathode filament 6 and the heating loop so constituted is as before connected to the negative pole 2 of the main generator. The anode of the valve is connected through the booster field winding 26 to the positive pole of the main generator A. The counter booster armature 27 is connected in series with the main generator shunt field winding 28 across the positive and negative poles of the main generator.

The valve 7, the winding 26, and armature 27 may be of comparatively small current carrying capacity. As the speed of the coupled machines rises the voltage generated in the alternating winding of armature 1 increases and the filament 6 becomes heated. Beyond a certain determinate speed any slight increase causes a greatly increased conductivity-of valve 6. Up to this speed the counter booster generator B remains practically unexcited and a powerful cur rent flows in field winding 28 of the main generator which is consequently strongly encited and giving its maximum voltage.

A very slight increment of speed acting as shown allows current to flow through the counter boosting field winding when the an mature 27 yields a greatly increased voltage op nosed to the main voltage.

ence the field excitation of the main generator falls as the speed increases maintaining a virtually constant voltage with small excitation losses.

This arrangement is very suitable for the practical application of the system to large generators in which the losses in ballast resistances, valve excitations or in differential windings are not negligible.

Figure 4 shows an alternative method of connecting the cathode filament, namely to the secondary winding 29 of a transformer the primary winding 30 of which is fed by pulsating current passing from the intermediate brush 31 to brush 2.

The brush 31 bears upon the single slip ring 32 which in this modification is connected to one point on the peripheral conductors of armature 1 or to equipotential points if the said armature is multipolar.

The potential of ring 32 thus connected varies cyclically from that of the pole 3 to that of pole 2, and this pulsation of potential gives rise to alternating currents through filament 6 which increase of the machine.

The points on the armature winding of maximum potential difference may be con nected to two slip rings and the transwith the speed ldtl former wmding 30, may be connected across such slip rings.

Figure 5 indicates another modified low pressure supply to the loop circuit.

The loop including brush 2, part of the winding of armature 1, brush 33 and the filament carries a comparatively large current at a low volta e. The armature in this case co-act-s wit three brushes 2, 3, and 33.

The relative circumferential displacement of brushes 2 and 33 may be only a few electrical degrees and the voltage between them low.

Figure 6 indicates a modified form of loop circuit supplied by alternating current in which three slip rin 34, 35, and 36 are used in connection wit a winding 37 arranged on armature 1. In this arrangement the middle point of the winding connects the slip ring 35 on which brush 38 bears. This brush is directly connected to pole 2, the other two brushes 39 and 40 connecting the terminations of winding 37 to the filament 6. By this method the control current from the anode flows first through one limb of the filament and then through the other limb alternately causing a very equable heating efi'ect.

Fi re 7 shows a further arrangement in whic a single field winding 41 and a resistance 42 is used. The field winding is connected from a mid-potential brush 43 to one termination 44 of the resistance 42 the other termination of which connects directly to pole 3.

The point 44 is connected to the anode 12 directly or throu h a resistance 45. The cathode is .connecte to pole 2 and may be excited by any'of the means herein described, although the arrangement em ployed in Figure 1 is shown.

When the machine is running at and above a predetermined speed the resistance of valve 6 falls and the potential of the point 44 more and more closely approximates to that of mid-potential brush 43, hence the current through field winding 41. deciines, the output voltage remaining practicaily steady.

When the machine is attached to a prime mover which may not only vary in speed but may rotate in one direction and sometimes in the opposite sense, the dynamo crushes may be connected to the rest of the apparatus as herein set vforth through a change-over switch 46 which is automatically thrown over in any known manner when the rotation of the armature reversed.

In such case, the mid-potential brush 43, if such is employed, need only have a fixed connection to Winding 41 of Figure 7. When the switch is so employed the system here set forth may be more readily used for l nent, these lamps being singly or in parallel with resistance, connected in series with the cathodic filaments, cease to glow if such filaments become ruptured.

As the current distribution in the cathode filaments is not uniform owing to the flow of thermionic current from the anode it is preferable to use a filament of varying cross section, the section of each element of the cathode being proportioned to the current flowing across the section in such manner that no excessive heating of any particular element of the filament shall take place. Such non-uniform filaments can be obtained by electro-chemical or chemical solution of a portion of the filament or by mechanical means.

The dynamo when arranged to operate the valve filaments on alternating current may be so constructed as to deliver a certain amount of such alternating current to an outside circuit, as will be readily under stood by those versed in the art, without further explanation. i

Various slight changes might be made in the general form of the parts described without departing from my invention. and hence I do not limit myself to the precise details set forth, but consider myself at libarty to make such slight changes and alteration as fairly fall within the spirit and scope of the appended claims.

I claim 1. The combination with a dynamo elec tric machine, of a valve having a filament therein affected by current generated by said machine in a closed loop circuit including the filament one point of which circuit 13 connected to the negative pole of the dynamo.

Q7 The combination with a dynamo electrio machine, of a thermionic means having a filament and generating means for produc in g current in response to the movement of the dynamo, said generating means and the filament of the thermionic 11158-118 disposed in a closed loop it, one point of which circuit is connect. to to the negative pole of the dynamo.

3. In a device of the character described comprising a dynamo electric machine, a

valve having a. filament therein affected by current generated by said machine in a cl loo-p circuit including thefilament, one point of which circuit is connected to the negative pole of the dynamo, and controlling the voltage of said dynamo electric machine.

t. The combination of a generator having a shunt field, a differential winding, a thermionic means includin a uni laterally conductive velve tube of t e incandescent cathode type having a. filament therein affected bcu-rrent generated b said machine in a osed loop circuit inc udi the filament, one point. of which circuit is connected to the negative pole of the dynamo, the anodic plate of the valve being connected in a circuit with. the differential Winding, whereby at a preleteivnined speed, an increase of current will be effective through the differential Winding to maintain a relatively constant volta e of the generator.

5. n electrical apparatus comprising a dynamo, an armature winding therefor, a difi'erenitial Winding, thermionic means having a filament therein affected by current, a closed loop circuit in which said filament is disposed, a connection between one pant of said circuit and the negative pole out the dynamo, and e connection between another port of said circuit and the differential winding.

6. in e dynamo electric machine commieing an armature, a field winding therefor, 11. oounter field, a. thermionic means having a filament therein affected by current generated by said machine in a closed loop circuit including the filament, one point of which circuit is connected to the negative pole of the d namo and having an incandescent cath e and an anodic late connected respectively with said win 'ngs, for effooting voltage control of the said dynamo electric machine.

7. The combination of a dynamo electric machine having a shunt field, and thermionic means associated therewith for effecting voltage re lat-ion, and having a. filament therein ad oted b current genereted by said machine in a c osed loop circuit including the filament, one point of which circuit is connected to the negative pole of the dynamo.

8. Fire combination of a generator having a shunt field, a. battery, and thermionic means comprising a bi-anodal valve for regulating the voltage of the generator, and charging current to the battery, and having a filament therein afl'ected by eminent generated by said machine in a closed loop circuit including the filament, one point of Which circuit is connected to the negetive pole of the dynamo.

WILLIAM JOHN RIGKETS.

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