SU98999A1 - Apparatus for improving commutation of AC collector machines - Google Patents

Description

The complication of the switching conditions in the AC collector machines as compared to the switching of the DC machines is a result of the fact that in the circuits of the short-circuited sections of the core windings, in addition to the emf. self-induction, eh, e transformer emf arise. due to the time variation of the main flux of the machine. Harmful effect ed, -c. self-induction in AC collector machines, i.e., their additional poles, are usually easily limited by successively connecting the windings of the additional poles into the main current circuit of the machine. Harmful effect of transformer emf limit much more difficult.

The known devices designed to improve the switching conditions of the collector machines of alternating current, i.e., their additional poles, consist of adjustable generators or transformers supplying the windings worn on additional poles. But the magnitude of the transformer emf is proportional to the magnitude of the main magnetic flux of the machine, and in phase it lags behind the magnetic vector

flow angle -y. Therefore, to compensate for the transformer emf.

in the switching zone, under the additional poles, it is necessary to create a component of their magnetic flux corresponding not only to the magnitude but also to the phase of the transformer emf.

In the described device, in order to expand the limits of full compensation of the transformer emf. in switched sections, a phase regulator is included in the overcurrent circuit, which allows independent and smooth adjustment of the phase of the flow of the auxiliary pole.

FIG. 1, 2, and 3 depict the circuit diagrams of the described device in single-phase and three-phase collector circuits.

No. 98999-2 -

FIG. 1 is a schematic diagram of the feeding of the winding of the additional MFC poles in the proposed device.

The voltage Up is supplied through the phasing regulator FR, which allows to regulate the phase of the feed current in any necessary limits. The magnitude of the supply voltage Un varies depending on the mode of operation of the machine so that the supply current / varies in proportion to the frequency of the flux f and the magnitude of the main magnetic flux Φ and inversely proportional to the speed of rotation of the machine n. the device is available in series with the winding of the additional poles of the DCT, and by feeding the winding 0/7 (Fig. 2) located on the same additional poles; in the latter case, the winding can be designed for overvoltage.

Fig. 2 is a schematic diagram of the proposed device as applied to a single-phase series collector motor of a traction type. The diagram shows the option of feeding additional poles using an OP winding fed through a phase-regulator FR. This option has the advantage of allowing compensation of transformer emf. all motors from one installation, since the windings I of all engines in this case can be activated in series. The single-phase mains voltage is converted to three-phase for powering the phase-shifter using a single-phase-three-phase motor generator set consisting of a single-phase synchronous single-phase motor and a three-phase synchronous generator of the TSG. Feeding voltage Ua in this circuit can be controlled by adjusting the excitation current with a regulating device RU that reacts to the operating mode of the collector engine. The compensating device described scheme allows for the compensation of the transformer emf under the generator operating mode of the machine under the conditions of regenerative braking.

FIG. Figure 3 shows a schematic diagram of the proposed device as applied to a three-phase collector generator with stator excitation. The diagram shows the option of adding additional current to the successive windings of the additional poles of the machine. The windings of the additional poles of the NDC are fed through a step-down transformer Tr with voltage regulation of the feed Un by changing the transformation ratio of the transformer Tr. The voltage to the transformer Tr is supplied via the phase-locked phase converter from the excitation supply circuit of the collector generator. Such a power supply system of the compensating device gives a proportional change in the feed voltage and n depending on the exciter current of the generator. The use of the described device can significantly reduce the size and weight of the machines for a given power, as due to the good compensation of the increased transformer e.s. large magnetic fluxes may be allowed on the pole.

Subject invention

A device for improving the commutator commutation of alternating current machines equipped with additional poles, magnetically adjustable in magnitude, and additional current, characterized in that in order to expand the limits of full compensation of the transformer emf. in the commutated sections, the phase regulator is switched on in the additional current circuit.