US1621452A - Means for regulating the voltage of dynamos of variable speed and load - Google Patents

Description

March 15, 1921. 1,621,452-

H. BENIT MEANS FOR REGULATING THE VOLTAGE OF DYNAMICS OF VARIABLE SPEED AND'LOAD Filed Aug. 13/ 1925 Patented Mar. 15, 1927;

UNITED STATES PATENT OFFICE.

HENRI IBENIT, OF PARIS, FRANCE, ASSIGNOB T LA SOCIETE DITE LECLATRAGE DES VEHICULES SUB RAIL, OF PARIS, FRANCE.

MEANS EOR'REGULATING THE VOLTAGE 0F DYNAMOS OF VARIABLE SPEED AN LOAD.

Application filed August 13, 1925, Serial No. 50,060, and in France September 20, 1924.

The present invention relates more particularly to vibrating regulators having two contacts and intended for the regulation of the excitation of dynamos with variable speed or load of the type employed in the lighting of vehicles.

Figures 1 to 6 are diagrammatic views of several embodiments of the invention.

Inthe drawing 1 denotes the armature of the dynamo, 2 its shunt exciting winding, 3 the resistance in series with this winding and 4 the movable blade pivoted at 0 and adapted to be moved in one direction by the spring 6 in order, through the medium of the fixed contact 7, to short-circuit the resistance. The movable blade 4 is adapted to be moved in the other direction by an electro-magnet 5,fthe coil ofwhich is branched to the terminals of the dynamo in order, through the medium-of the contact 8 and the resistance 9, to shunt the exciting winding 2.

It is also known that for the object of extending the limits of regulation of the above device, there may be used for the resistance 3 a metal having avariable temperature coefficient, e. g. iron under conditions such that its resistance increases in very large proportions when the current traversing it tends to increase.

In order to increase further the extent of the limits of regulation of a given dynamo, without producing sparks which would dainage the contacts of the regulator, there may be adopted in accordance with the invention an arrangement such as that illustrated diagrammatically in Fig. l of the annexed drawing.

10 represents a resistance in parallel with the resistance 3 when the automatic switch 11 is closed. This switch is arranged in a manner similar to that of a vibrating regulator and comprises a plate attracted in one direction by a spring 12 and in the other by an electro-magnet 13, the coil of which is connected in shunt with the terminals of the resistance 3. Resistances 14 and 15 are dis posed in series'with the coils of the electromagnets 5 and 13 and may be variable if desired.

The operation of the arrangement is then as follows. On starting, the switch 11 is closed, the blade 4 of the regulator is in contact with the fixed terminal 7, and the resistances 3 and 10 in parallel are entirely shortcircuited by the regulator. The field winding 2 may thus supply the maximum possible excitation.

When the dynamo has attained the volt age for which the vibrator is regulated, the blade 4 commences to vibrate, the current in the field winding 2 commences to fall at the same time as the voltage at the terminals of the resistance 3 and 10 (which would at first be Zero) commences to increase, and the current traversing the coil 13 increases in proportion. As soon as the latter voltage reaches a certain value, the switch 11 opens and the resistance 10 is disconnected. A sudden increase in the value of the resistances remaining in series with the field magnets takes place, but the regulator instantaneously makes the necessary correction in such manner as to maintain constant the voltage at the terminals of the dynamo.

If the speed of the dynamo continues to increase or if the load varies, the regulator acts in the same manner as in the known arrangement; in articular, for high speeds and low loads the blade 4 vibrates against the fixed contact 8 in such manner as to shunt more or less the field winding 2.

On stoppage the inverse operations take place when'in consequence of the operation of the blade of the vibrator, the voltage at the terminals of the resistance 3 has become sufiiciently low, the switch 11 is automatically closed and the resistance 10 is put in parallel with the resistance 3. Nevertheless, in order that the switch 11 should not itself vibrate, it is necessary that there should be a snfiicient difference between the voltage at the terminals of the electro-magnet 13 which opens the switch and that which closes it.

Just as with the known arrangement, the extent of the limits of regulation may be increased by employing for the resistance 3, and evenfor the resistance 10, a metal having a high temperature co-efiicient.

The conditions of regulation may also be improved or modified by providing in conjunction with the arrangement above-described certain known devices, such as the automatic insertion of a resistance in series or in parallel with the coil of the electromagnet of the vibrator, (in order to produce the effect often described as compensation) the compoundin of this electro-magnet, etc.

The extent 0 the limits of regulation of the dynamo may be still further increased by employing as indicated in Fig. 2 several auxiliary resistances 10, 10', etc., and several switches 11, 11, etc., for theseresistances. A necessary condition in this case is that the electro-magnets 13, 13', etc., controllingthe switchesv should be regulated in such nuanner as to act successively and-at the desired time.

. Fig. 2 shows for the coils of these electromagnets 13, 13', etc., independent circuits arranged in shunt with the terminals of the resistance 3, but these coils could quite well be arranged also in series in a single circuit arranged in shunt with the terminals of this same resistance 3.

Fig. 3 shows a variation of the preceding arrangement in which one-of the groups (resistance 10 and switch 11) is branched to the terminals of the field winding 2, in lieu of being branched to the terminals ofthe resistance 3.

In this case the order of the operations of closing and opening the switches 11, 11, should be determined in such manner that when the speed of the dynamo increases, the switch 11 first opens and the switch 11 closes later; when the speed of the dynamo fallsthe switch 11 should open first and the switch 11 close later.

In all cases there should be utilized the voltage at the terminals of the field winding itself to cause the operation of the switches 11, 11' etc., and it would be sufiicient to change the direction of action of the springs and of the elective-magnets of these switches.

As indicated in Fig. 4, it may even be advantageous to branch the elcctro-magnet 13 of the switch 11 to the terminals of the resistance 3 and the electro-niagnet 13' of the switch 11 to the terminals of the field magnets.

Fig. 5 shows another variant of the particular arrangement forming the subject of the present invention. In this variant a resistance 16 in series with the resistance 3, (and consequently with the field winding 2) may be short-circuited or put in circuit by the automatic switch 11. The circuit of the coil 13 and of its resistance 15 is branched in shunt to the terminals of both of the resistances 3, 1G, in series with the field winding 2.

The operation of the device in the arrangement referred to will'be easily followed, having regard to the explanations given in connection with the arrangement shown in Fig. 1.

For dynamos of a certain power there may be used two or more than two resistances 16, 16, etc., (see Fig. 6) and as many corresponding switches 11, 11, with the double condition of exciting each of the electro-magnets of these switches by means of a coil under the influence of the differarrangement.

- Havin now )articularl described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. Means for regulating the voltage of dynamos of variable speed and variable .load, with vibrating regulators having two contacts, comprising in combination with a dynamo having a field winding and a resistance in series with the field winding, a second resistance branched in parallel with said first resistance, an eleetro-magnetic automatic switch in the connection between the second resistance and the field winding, the magnet of said switch having its terminals connected to the terminals of the first named resistance, whereby said magnet is under the influence of the'difierence of potential at the terminals of the resistance in the field winding.

2. Means for regulating the voltage of dynamos of variable speed and variable load, with vibrating regulators having two contacts, comprising in combination with a dynamo having a field winding and a resistance in series with the field winding, a second resistance branched in parallel with said field winding, an electro-magnetic auto matic switch in the connection between the second resistance and the field winding, the magnet of said switch having its terminals connected to the terminals of one of the elements of the field winding, whereby said magnet is under the influence of the difference of potential at the terminals of said element.

In witness whereof I have hereunto set my hand.

HENRI BENIT.

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