US1416236A - Electrical system - Google Patents

Description

.F', PU-NCA.

ELECTRECAL SYSTEM. APPLICATION FILED SEPT-25,1911. RENEWED MAR.-2,1922.

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APPLICATIO 'N FlLED SEPT. 25, I911- RE NEWED MARLZ. I922- 1,416,236. Patented May 1 ,1922.

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APPLICATION FILED SEPT. 25. 1911. RENEWED MAR.-2. 1922.

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ELECIRICAL SYSTEM. APPLICATION FILED SEPT. 25, NHL REPEWED MAR-2 1922.

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UNITED STATES hmnxmn PUNGA, or LIEGE, BELGIUM.

ELECTRICAL SYSTEM.

Specification of Letters Patent.

Patented May 16,1922.

Application filed September 25, 1911, Serial No. 651,074. Renewed March 2, 1922. Serial No. 540,667.

(GRANTED UNDER PROVISIONS OFTHE ACT-0F MARCH 3, 1921, 41 STAT. L, 1313.)

To allwh'omitmcy concern):

Be it known that I, FRANKLIN PUNGA, a

subject of the German Emperor, and residfor supplying vehicles with electrical energy,

particularly for illuminating purposes, in-

cluding a dynamo electric machine driven through the propelling motion of the vehicle .or from the power motor, with batteries charged from time to time by the dynamo and from time to time feeding the net-work or mains. I

The difficulties peculiar to such an energy supply system are on the one hand due to the fluctuations in the number of revolutions or speed of the dynamo and on the other hand due to the fact that the battery is frequently charged excessively when the current in the mains is weak or is charged insuffi ciently when a strong current is required in the mains.

In order to remove these drawbacks it has been proposed to cause the dynamo to supply a constant current and to allow this current when there is little load on the mains to act on the battery, and when there is a heavy load on the mains to act directly on the same. In adopting this method drawbacks have arisen which are due to the fact that the battery is charged when there is a light upon the load on the mains, for example, by controlling the dynamo excitation accord ing to the current in the mains by causing this main current (or a current proportional thereto) to flow through a field winding in the same direction as the current in the normal field winding and so to increase the mean or average charging current when a strong current flows in'the mains and to decrease the same when that current is weak.

The invention also consists in an arrangement of this kind in which one battery is being charged whilst the other discharges into the mains in which arrangement the dynamo is preferably excited by current in three windings viz, (a) the usual winding (6) .a positive compound winding fed tional thereto and (c) a negative com-' pound winding excited by a voltage dependenton the potential diiference between the batteries, resistance being provided for varying such excitation as desired.

This invention also consists in an arrangement of the nature above referred to in which for the purpose indicated below, an exciting winding is arranged between the dynamo and the battery and is adapted to weaken .the excitation of the dynamo with charging current and vice versa.

The invention also consists in an automatic switching device for varying the excitation and methods and means for operating with single batteries.

This invention also consists in the improved vehicle lighting systems hereinafter indicated.

Referring to the accompanying drawings:

Figures 1 and 2 show apparatus according to two forms of the present invention.

Figures 3 and 4 show switch details;

Fig. 5 shows an arrangement of switch contacts for operating according to Fig. 2.

Figure 6 shows a scheme according to a modification.

Figure 7 illustrates by curves one form of the invention;

Figures 8 to '13 show modifications.

In Figure 1 the dynamo 1 is excited by the shunt winding 4 having, a regulating resistance 9 in its circuit and the reverse or negative compound winding 5 (with regulating resistance 10 in circuit) connected to the mains I and II with lamps 30 by way ofv switches (described in detail below), 6, 7 and equal batteries 2 .and 3. The batteries are also joined to the dynamo directly at one pole and by way of the switches 6 and 8 at the other, the switch 6 permittin the batteries vto be connected respectivey to the mains or dynamo alternately. The switch 8 is only brought into operation when the speed of the dynamo-exceeds a certain limit, and the switch 7 serves for short circuiting the winding 5 so that the two batteries can act in'parallel.

In Figure 2 a positive compound field winding ll is provided in series with the mains and regulable by the resistance 12.

Details of the switches 6 and 7 in one form are shown in Figures 3 to 5.

This switching device serves to exchange the batteries 2 and 3 without interruption of the current from the mains and in consequence without fluctuation of the light, and also to bring the dynamo into circuit. The device has the features of very simple construction, absolute reliability and exact operation. The switch consists substantially in a fixed disc 13 and two moving discs 14: and 15. The disc 15 may rotate through an angle of 90 under the action of a suitable driving agency such as a crank 18 against the action of a restoring spring 5. The two moving discs are coupled in such manner that the disc 15 turning in the direction of the arrow 19, see Fig. 3, rotates the disc 14;

through an angle of 90 by means of the pawl 16 engaging the ratchet 17. The disc 15 turns through an angle of 90 and is preferably arrested by a pawl 20 preventing the spring 5 from pulling back the disc 15. lVhen the pawl 20 is released the disc 15 alone returns to its initial position under the action of the spring 5, while the disc 14 remains in its new position.

As shown in Fig. 4 four contacts are arranged on the fixed disc 13. Opposite these contacts a, b, c, d, the moving disc 14 has contact studs 6 and 7 each of which can con nect respectively with two of the contacts, a, b, c, d. On the moving disc 15 are mounted two pairs of contacts, g, h, and Z, m and adjacent to these contacts, two fixed contact studs Z and in are provided at an angle of 180 apart, so that the moving disc 15 when turned through an angle of 90 connects together one'or other pair of contacts, g, h, or Z, m, through one or other of the studs 2', 7c.

The operation of the switch contacts and the connections of these contacts is illustrated diagrammatically in Fig. 5. The contacts a and b are each connected respectively to the batteries 2 and 3 and the contacts d and c with the mains I and the dynamo 1 through the contact of disc 15 respectively. The contacts g and h are in connection with the ends of the coil 5 and the contacts Z and m with the dynamo 1 and the contacts 0 respectively. As will be seen in the illustrated position of the discs 14 and 15 the battery 3 is connected with the mains through the contacts 5. (7, connected together by the stud f. The dynamo is placed in circuit with the battery 2 through the con tacts I. m. connected by the stud K1. and contacts 1/ connected by stud c, and the contacts y. it. being open, the winding 5 is consequently traversed by a current depending on the difference of the E. M. Fs. of the batteries.

This position of the permutator switch in which the d \'namo and one of the batteries feeds the mains may be changed to a podlion putting the dynamo out oi circuit and connecting the two batteries in parallel with the mains. When the crank 18 is turned through an angle of 90 from the position A to the position B in the direction of the arrow 19, the two discs let and 15 are simultaneously turned into a position in which the contacts Z, m, are disconnected while the contacts g, it, are connected by the stud z and consequently the winding 5 is short circuited. The battery '2 is connected with the mains through the contacts a, d, connected by the stud e, and with the battery 8 through the contacts 11., g, and stud 2', this position of the switch being provided for the case when the dynamo is at rest. When the crank 18 is returned to the position A after having freed the pawl 20, the dynamo again works in combination with one of thebatteries of the mains, the other battery being charged, but now the two batteries are changed, the battery 3 being charged with the battery 2 con nected with the mains.

The operation according to Fig. 1 takes place in the following manner. The exciting winding 5 supplies a current which is proportional to the difference of the E. M. F. of the two accumulators 2 and 3 and produces a magneto .motive force opposing that produced by the normal shunt winding 4. WVhen this difference is small the current in the winding 5 will be weak and consequently the excitation will then be only slightly less than if the bobbin 4 alone were present, but as the difference increases the amperev turns of the coil 5 increases to a much greater proportion than the ampere turns of the coil 4, the two coils 4; and 5 being suitably designed for this purpose. This results in a reductionioi the total ampere turns so that a certain E. M. F. of charge cannot be exceeded whatever the speed of the dynamo.

The winding 11 traversed by the current from the mains operates to augment the normal excitation in such manner that the mean current of charging varies in proportion to the mains current. Thus when a large number of lamps is in circuit there is an increase of the mean charging current whereas a reduction of the mains current produces a diminution of the charging current with the consequent advantage that in train lighting forexample the charge of the battery 2 is heavier during the night than during the day. The coil 5 in each case has the same effect as in the arrangement of Fig. 1, i. e.. preventing the charging E. M. F. from becoming excessive.

The use of the normal shunt coil 4 is of particular advantage in the case where the current in the mains remains Zer for a long time as it prevents a discharge of the batter v through the dynamo circuit since there is still a small charge current developed by the dynamo if the coil 4 be suitably designed. This constitutes a great advantage in the upkeep of the system since a weak and constant charging current is very favourable to the battery. A weak charging current would for example be produced in train lighting during the day when the current required by the mains would generally be nil.

In the case however where the current supplied to the mains remains at zero for a considerable time,the battery connected with the mains is gradually charged with the weak current proceeding from battery 2 to battery 3 through the coil 5 so that the E. M. F. of the battery connected with the mains increases, causing an excessive charging of the battery 2. This possibility may be avoided by suitably designing the coil 5 and the armature reaction of the dynamo 1.

A greater reliability is obtained however by the introduction into the mains of an additional resistance. In Fig. 5 it is seen that this resistance 24 provided with a switch is inserted across the mains I and IL The losses caused bythis resistance are so small that they are negligible. The switch 25 for this resistance is preferably so arranged that the resistance is only brought into action when the current in the mains is very small or equal to zero or where the dynamo is broughtinto circuit.

When using the resistance referred to above there is the risk that if the resistance is to be connected up by hand this connecting up may be forgotten or if automatic it might be that this connecting up does not take place owing to some disturbance or other. Further the resistance necessitates a loss in energy even though small and if a small current is chosen in order to decrease this loss in energy the counter excitation furnished by the winding acted upon by the difference in the battery voltage may become so small in proportion t the other factors determining the charge that said counter excitation no longer exerts the necessary weakening effect which it should exert.

In these special circumstances it. is preterable not to arrange the reverse field winding between the two batteries but betweenthe battery which is to be charged and the dynamo in such a manner that the excitation of the dynamo is weakened with charging current and increased with discharging current. In the case of a single battery also the reverse field winding can be placed between the battery and the dynamo.

In Figure (5 the dynamo 1 is excited according to the differential effect of windings 5 and 11 connected in'series with the armature and battery 2 and the mains I, II re spectively.

Figure 7 is a diagram the ordinates O Y O Y of which represent values of current,

the winding 5, in which case instead of a charging current flowing through the dynamo armature a discharging current passes through the same. With a moderate load on the mains the current curve B is produced whilst with a higher load the current C results, and in consequence of the cooperation of the windings 5 and 11 for the field excitation of the dynamo a charging current increasing with the load results.

The winding 5 can be wholly or partly replaced by designing the dynamo with a large armature reaction, for instance, by making the pole are very small and by moving the brushes in the direction of rotation. In this case when no current is flowing in the mains and when the battery 2 is being charged the excitation is obtained by causing the machine 1 to run as a motor and the armature ampere turns which normally are arranged in opposition to furnish the excitation' This arrangement is ticularly suitable for cases where the vehicle moves only in one direction, for instance, in motor cars, boats and similar vehicles. In railway trains it is advisable to move or adjust the brushes if by doing so a reversing or adjustment of the armature i. e., a further shifting of the brushes through 180 electrical degrees is effected at the same time.

When there is no load on the mains it is advisable not to allow the batteries arranged in the circuit of the dynamo to be discharged, but on the contrary to cause the dynamo to generate such an amount of current that only a slight charging of the batteries takes place so that the current curve A in Figure 7 will be wholly or partly above the abscissa axis. This result can be ob- .tained by the shunt winding 4 as shown in Figure 8. In this figure the dynamo l is provided with the three windings. 4 the normal shunt winding which may be ad justed by the regulable resistance 90, 5 the negative field winding connected between the dynamo 1 and the battery 2 which may be adjusted by means of the regulable resistance 9 and the winding 11 with excitation depending on the load in the mains.

It will be understood that the single battery arrangements can be applied to two batteries so that one is discharged and supplying the, mains with current while the other is being charged, the reversing oi the two batteries being efl'cctcd either automatically for instance at regular time intervals paror at certain stops, or after having travelled over certain distances or if required by hand.

When the dynamo is at rest or if its speed is below a predetermined limit preferably both batteries effect the current supply.

Figure 9 shows one application of the system illustrated in Figure 8 to two batteries, 2 and 3, of which the battery 2 is being charged whereas the battery 3 supplies the mains with current.

The connections of the various windings are in this figure similar to those in Fig. 8.

Figure 10 shows an arrangement of the batteries 2 and 8 serving a similar purpose, the batteries being provided with a common terminal whereas the other terminals are controlled by a reversing switch 190. Further a circuit maker or breaker is provided. In this case the negative field winding 5 is arranged between the dynamo 1 and the reversing switch 190 the other windings being connected as before.

The interposition of a resistance 20 between the battery terminals which are reversed is of particular advantage for the present system. This resistance should. preferably be so dimensioned that when charging one battery a current will flow from the same to the battery which is being discharged, said current being a little less than the smallest current in the mains coming into question. By this means the battery connected to the mains'is only discharged to a very small extent. In cases where always all the lamps of a particular carriage are lighted at the same time the current flowing through this resistanceinto the mains will be a little/less than the discharging current.

Figure 11 shows a modified single battery arrangement in which the windings 4 5 and 11 are electrically connected as in Fig. 8 but a resistance 23 with switch 22 is arranged across the mains I and II for enabling charging to be effected whenever desired. When in this arrangement there is no load on the mains, the battery 2 is only charged to a very slight extent as the exciting winding 4 can be so controlled that the curve A (Figure 7) is only a very little above the abscissa axis, or even intersects said axis, at a certainspeed. In order to ensure the voltage of the mains being the same during the movement of the vehicle, as when.

"* "wo convy utators in which case the total of the two voltages is used for charging the battery 2 and the half or separate voltage is used for feeding the mains.

In special cases it may be advisable even when using the arrangement shown in Fig me 12 to employ a small resistance corresponding to the resistance 10 shown .in Fig ure 11in which figure it is arranged in series with the winding 11.

In order to be able when employing the arrangements shown in Figures 11 and 12 to charge the battery if so desired at any particular moment it is preferable to make provisions such as a switch 22 for connecting windings 41, 4 and 5'and short circuiting the mains I and II through a resistance 23. To avoid losses in this case the coil 5 is divided into several parts such as 51 and 52, Fig. 13 which can be changed over by means of a suitable switch 26, from parallel to series connection when it is desired to charge the battery, the normal position being in parallel as shown in the figure.

The employment of a single battery for instance as shown in Figure 11, is especially suitable for illuminating motor cars, boats and the like. In such a case the dynamo is driven from the power motor mostly through the intermediary of a transmission gear that is to say the dynamo can also be allowed to run when the vehicle is at a standstill.

Regulable resistances such as 9, 10 and 90 (Figure 8) can be applied where desired.

Among the advantages of the present invention it may be noted that the reversing of the batteries can be effected without interrupting the current flowing in the mains and consequently without causing a flickering, of the light. It is even advisable to reverse the batteries as frequently as possible, as by doing so the batteries can be charged more uniformly, so that this reversing of batteries can be carried out without causing a noticeable fiickering of the lights due to non-uniform voltage, but when adjusting and designing the dynamo, the losses in the accumulators during the periods of rest must be taken into account.

Having now described my invention what I claim asnew and desire to secure by Letters Patent is 1. In combination, a dynamo and two accumulators, a field winding for said d namo and a demagnetizing field winding or the same, a reversing switch connected with like poles of the accumulators and an additional winding in which load current flows, said demagnetizing and additional windings being connected to the said reversing switch.

2. In combination a dynamo, a shunt field exciting winding therefor, two batteries, the like poles of said batteries bein intercom. ne'cted and connected to the terminals of the dynamo and to the mains, a second field exciting Winding interposed between the dynamo and the batteries, a suitable resistance inter osed between one pair of like terminals of sald batteries, a change over switch adapted to place either of'said batteries in chargin connection, the other of said batteries being at the same time placed in discharging connection and a further field exciting winding connected in series in aforesaid mains;

as set forth.

3. An energy supplying system for vehicles particularly for illuminating purposes including in combination a dynamo, a battery, electrical connections between said dynamo and saidbattery, a further battery, electrical mains, electrical connections between said further battery and said mains, a field exciting shunt winding, a field coil influenced by the load current and assisting said shunt winding, and a further exciting winding connected between said dynamo and the battery to be charged and opposing said first windings with charging current; as set forth.

4. An energy supplying system for vehicles, particularly for illuminating, purposesfcomprising in combination a dynamo electric machine, a battery connected therewith, a further battery connected in parallel with said first battery and supplying the current to the'mains, afield exciting shunt winding, a field coil influenced by the load current and assisting the first winding, a further exciting winding connected between the dynamo and battery to be charged and opposing said first windings with charging current and a suitable resistance interposed between one pair of like terminals of said batteries whereby a small current is supplied to the load from the dynamo; as set forth.

5. An energy supplying system for vehicles particularly for illuminating purposes, comprising in combination a dynamo, a shunt field exciting winding therefor, two batteries the like poles of said batteries being interconnected and connected with the terminals of the dynamo and to the mains, a second field exciting winding interposed between the dynamo and the battery to be charged and opposing the shunt field winding, a third'field winding traversed by the load current and operating in the sense of the shunt winding, a suitable resistance interposed between one pair of like terminals of said batteries and a change over switch adapted to place either of said batteries in charging connection and the other at the same time in discharging connection; as set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

FRANKLIN PUNGA.

Witnesses:

H. A. JoHNsoN, How. J OHNSQN.

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