DE1081967B - Arrangement for supplying a load with a variable voltage from an alternating voltage source of essentially fixed voltage - Google Patents

Description

The invention relates to a transformer arrangement for feeding electrical consumers variable voltage and in particular to an arrangement for feeding electric DC traction motors via rectifier arrangements.

The voltage supplied to the consumer is generally set by tap switching the secondary windings of a supply transformer. It is also known for such Usually transformers provide several secondary windings, which allow further switching combinations and expand the operating range of the transformer. In a known device for voltage adjustment in AC systems with a main transformer and an auxiliary transformer With a smaller capacity, an additional winding on the main transformer acts with one winding on the Auxiliary transformer together, the two windings through a third transformer via a Switches are interconnected. Here, the effort is due to the arrangement of an additional Auxiliary transformer relatively large.

In another known transformer arrangement with several secondary windings are for the purpose Phase adjustment the windings required for this are operated in economy circuit and are operated by the V-connected windings of a multi-winding transformer excited. In this known arrangement, the adjustment range in terms of the size of the However, voltage is only determined by the taps on the secondary windings.

The aim of the invention is to create a feed arrangement which, with a simple structure, has a large adjustment range and is particularly suitable for supplying DC traction motors in rail vehicles is.

For this purpose, an arrangement for supplying an electrical load is characterized by a variable voltage from an alternating voltage source of essentially fixed voltage according to the invention by combining a main transformer with a main secondary winding and including first and second auxiliary secondary windings each having half the voltage the main secondary winding generated, with an adjusting arrangement, which with the first auxiliary secondary winding is connected and a variable between zero and a full voltage of the winding Voltage generated and adjustable with respect to the phase position of the voltage of the second auxiliary secondary winding is, wherein the actuator assembly and the second auxiliary secondary winding with the main secondary winding and the load resistor are connected in series via a double-pole changeover switch, in such a way that

arrangement

for feeding a consumer

with a variable tension

from an AC voltage source

of essentially more fixed

tension

Applicant; ·

The English Electric Company Limited,
London

Representative: Dipl.-Ing. C. Wallach, patent attorney,
Munich 2, Kauringerstr. 8th

Claimed priority:
Great Britain 18 July 1955

Henry Bolton Calverley, Bradford, Yorkshire

(Great Britain),
has been named as the inventor

that the resulting output voltage of the actuator assembly and the second auxiliary secondary winding the voltage of the main secondary winding either decreases or increases and so a voltage change from zero to the voltage of the main secondary winding when the changeover switch is in one position is located, and from the voltage of the main secondary winding to twice the voltage of this when the changeover switch is in the other position.

This training ensures that the voltage in the simplest possible way from zero to the twice the value of the main secondary winding can be changed as the voltage of each of the two Auxiliary secondary windings is half the voltage of the main winding and in the highest Voltage level, all windings are connected in series.

According to an advantageous embodiment of the invention, the variable transformer is designed in such a way that that the main secondary winding is tapped in the middle and this center tap with the Center of the load resistance is connected and that first and second auxiliary secondary.

OW 51W159

hung for each half of the main secondary development together with one S-part arrangement and one each Changeover switches are provided, the two actuating arrangements and the two changeover switches together operated so that a simultaneous voltage change on each half of the load resistance is achieved.

The invention is particularly used in electrically powered vehicles that are driven by a are fed by an external AC voltage source and have one or more DC drive motors, which are fed via rectifiers arranged in the vehicle.

Further details and advantages of the invention emerge from the following description of FIG Embodiments on the basis of the drawing.

Figs. 1 and 2 illustrate two different methods of practicing the invention at Application for electrically powered vehicles. In the figures, the same parts are provided with the same reference numerals.

According to FIG. 1, a main transformer 10 has a primary winding 10a fed by a contact line 11 via a current collector 12, a main secondary winding 10b and two auxiliary secondary windings 10c and 10e. The voltage of each of the windings 10 c and 10 e is half the voltage of the winding 10 b.

On the auxiliary secondary winding 10c there is a variable transformer 40 with two movable contacts, which directly slide along the winding and perform the same movements in opposite directions. When the movable contacts are in the middle position, the voltage tapped from the winding 10 c is zero. Moving the contacts to the ends of the winding causes the voltage to rise steadily up to a maximum voltage of the auxiliary secondary winding 10c, the voltage being either in phase or in antiphase with the voltage of the auxiliary secondary winding 10e, depending on the direction of movement.

The main secondary winding 10- & feeds a full-wave rectifier in a bridge circuit, which consists of rectifiers 44 and 45, via a series circuit consisting of a changeover switch 42, the auxiliary secondary winding 10 ^ and the moving contacts of the variable transformer 40. Four DC drive motors M 1 to M 4 are from the direct current side of the rectifier is fed via smoothing chokes 14, the motors being connected in two parallel circles with a compensating connection 47 between the centers of the two circles.

If the movable contacts of the variable transformer 40 are set so that an output voltage of the same size and phase of the voltage of the auxiliary secondary winding 10 e is achieved, the resulting voltage of these two windings is equal to the size of the output voltage of the main secondary winding 10 b. When the changeover switch 42 is in such a position that the resultant voltage is in phase opposition to the voltage of the winding 10 &, the resultant voltage applied to the rectifier bridge circuit becomes zero. This is the operating condition under which the vehicle is at rest.

An acceleration of the vehicle is achieved in that first the contacts of the regulating transformer 40 to the opposite ends of the same are moved, the output of this transformer is uniformly reduced to zero and then 10 e is raised to the full value in counter-phase to the auxiliary winding. Under these operating conditions, the output voltage of the two windings 10 e and 10 c is zero. Now, by moving the contacts from their initial position to the opposite ends, the resulting voltage applied to the rectifier bridge circuit will increase from zero to the full voltage of the main secondary winding 10 &.

Then the changeover switch 42 is switched over, the phase of the resulting output voltage of the two windings 10 c and 10 e being rotated. However, this has no effect on the resulting voltage fed to the rectifier bridge circuit, since the resulting voltage of these two windings is now zero.

To further accelerate the vehicle, the contacts of the variable transformer 40 in returned to their original position, whereby the resulting

ao generating output voltage of the windings 10 c and 10 e is increased to a value which is equal to the arithmetic sum of the voltages of these two windings. Since the changeover switch has now been switched, the resulting voltage is now in phase with the voltage of the main secondary winding 10b , so that the resulting voltage fed to the rectifier bridge circuit is now increased to a maximum value, i.e. to a voltage which is twice the voltage the main secondary.

The arrangement shown in Fig. 2 differs from that according to Fig. 1 only in that the main secondary winding 10 b is tapped in the middle and connected to the centers of the motor circuits via a compensation connection 46, and auxiliary secondary windings 10 c? and 10 /, a further variable transformer 41 and a further changeover switch 43 are provided. The voltage of each of the windings 10 c to 10 / is equal to half the voltage between the center tap of the main secondary winding 10 δ and the corresponding outer end of the same.

The acceleration of the vehicle is achieved in exactly the same way as in the arrangement shown in FIG. 1, in that the movable contacts of the two variable transformers 40 and 41 are moved simultaneously in corresponding directions and the changeover switches 42 and 43 are switched over at the same time in the acceleration sequence will. In this arrangement, the voltage applied to the load resistor at both ends of the equalizing connection is changed, as in the arrangement according to FIG. 1, between zero and twice the voltage of the corresponding half of the main secondary winding 10b .

Claims (2)

Claim: 1. Arrangement for supplying a load with a variable voltage from an alternating voltage source of essentially fixed voltage, characterized by the combination of a main transformer (10) which has a main secondary winding (10 b) and first and second auxiliary secondary windings (10 c and 10 e) contains, each of which generates half the voltage of the main secondary winding, with an adjusting arrangement (40) which is connected to the first auxiliary secondary winding (10 c) and one between zero and a full voltage of the winding (10 c) generated variable voltage and adjustable with respect to the phase position of the voltage of the second auxiliary secondary winding (10 e), the adjusting arrangement (40) and the second auxiliary secondary winding (IO e) with the main secondary winding (10 b) and the load resistor are connected in series via a double-pole changeover switch (42), such that the resulting output voltage of the control arrangement (40) and the second auxiliary secondary winding (10 e ) either lowers or increases the voltage of the main secondary winding (10 b) and so Allows a voltage change from zero to the voltage of the main secondary winding when the changeover switch is in one position and from the voltage of the main secondary winding to twice that voltage when the changeover switch is in the other position. 2. Arrangement according to claim 1, characterized in that the main secondary winding (10 fr) is tapped in the middle and this central tap is connected to the center of the load resistor and that first and second auxiliary secondary windings (10 c, IQd or 1Oe, 10 /) are provided for each half of the main secondary winding (10 b) together with one control arrangement and one changeover switch each, the two control arrangements (40, 41) and the two changeover switches (42, 43) being actuated together so that a simultaneous voltage change on each Half of the load resistance is reached. Considered publications:
German Patent No. 651 005;
Austrian Patent No. 91082;
ETZ, 50 (1929), p. 525. 1 sheet of drawings © 009 510/159 5.60