CS220187B1 - A device for reducing brush and commutator wear of a DC 4-pole rotary machine - Google Patents

Abstract

The device according to the invention relates to DC four-pole rotating machines, the armatures of which are provided with parallel windings with equipotential couplings and is particularly suitable for high-power machines. The device is designed so that two secondary windings of a single-phase transformer are connected to two brushes of positive polarity and two brushes of negative polarity, or two single-phase transformers so that a first secondary winding is connected to the two brushes of positive polarity, which is provided with a middle terminal, which is connected to the supply terminal of positive polarity of the DC four-pole rotating machine. At the same time, a second secondary winding is connected to the two brushes of negative polarity, also provided with a middle terminal, connected to the supply terminal of negative polarity of the DC four-pole rotating machine.

Description

The device according to the invention relates to DC four-pole rotary machines whose anchors are provided with parallel windings with equipotential couplings and are particularly suitable for machines of high power.

The device is designed in such a way that two secondary windings of a single-phase transformer or two single-phase transformers are connected to two positive polarity brushes and two negative polarity brushes so that the first secondary winding is connected to the two positive polarity brushes. , which is connected to the positive polarity supply terminal of a DC four-pole rotating machine. At the same time, a second secondary winding is also connected to the two negative polarity brushes, also provided with a central outlet connected to the negative polarity power supply terminal of the DC quadrupole rotating machine.

Giant. 1

BACKGROUND OF THE INVENTION The present invention relates to a device for reducing the wear of brushes and commutators in a four-pole rotary machine, the armature of which is provided with parallel windings with equipotential couplings, and which is particularly suitable for high power machines.

It is known from experience that the brushes of the collecting device decrease rapidly when the current transferred by them drops below about 30% of the rated current of the machine. In this case, the commutator fins are also extremely worn.

It is known from the application AO 219 216 to prevent said undesirable effects by artificially applying alternating current to the brushes. The artificial load is carried out by means of two single-phase transformers, which are connected to the single-phase AC supply automatically when the DC current of the machine falls below 30% of the rated current. However, this device needs the machine to be equipped with four collecting rings, ie two for positive polarity and two for negative polarity. However, this device is disadvantageous in that it is only applicable to newly constructed machines, where four collecting rings are envisaged, already during their construction.

[0005] AO 221 368 also discloses a device enabling artificial current loading of brushes, which is also applicable to existing machines, but is limited to DC six-pole rotating machines.

The above drawbacks are eliminated by the brush and commutator wear reduction device, a DC four-pole rotary machine with parallel anchor winding and equipotential couplings according to the invention, in that two positive polarity brushes and two negative polarity brushes are connected with two the secondary winding of a single-phase transformer or two single-phase transformers, so that the two positive polarity brushes are connected to the first secondary winding, which has a central terminal which is connected to the positive polarity supply terminal of a DC · 4-pole rotating machine; a second secondary winding provided with a central outlet is also connected to the negative polarity power supply terminal of a DC quadrupole rotating machine.

The device according to the invention is simple and reliably reduces the wear of the commutator brushes and lamellas, thereby allowing correct commutation. It can also be used on machines equipped with only two slip rings.

An exemplary embodiment of a device for reducing the wear of the cans and commutator of a DC four-pole rotary machine according to the invention is schematically illustrated in the attached drawing, wherein Fig. 1 relates to positive polarity brushes and Fig. 2 negative polarity brushes of DC four-pole rotary machine. Since the apparatus can be formed either by a single-phase transformer with two secondary windings or two single-phase transformers, each of which is provided with one secondary winding, the primary windings of these transformers are not shown in FIGS. plotted. They are implied. only two secondary windings, one for the positive polarity brush circuit and the other for the negative polarity brush circuit. Both secondary windings have central outlets.

Giant. 1 - the first and second positive polarity brushes ΙΑ, 1B are attached to the commutator 2. For simplicity, only the two first equipotential couplings 3A are shown between the unlabeled commutator slats 2, which are shown at the moment when they rotate the anchor four-pole rotary machine armature to rotate those commutator slats 2 that lie beneath the positive polarity brushes IB. Between the two positive polarity brushes IB there is connected the first secondary winding 4A with the middle outlet, which is connected to the positive polarity supply terminal of the DC four-pole machine.

A similar arrangement is shown in Fig. 2, where the commutator 2 is provided with the first and second negative polarity brush 1C, ID. Among the unlabeled commutator slats 21, only two second equipotential couplings 3B are shown for simplicity, which are shown at the moment when the anchor of the DC quadrupole rotary machine rotates the negative commutator slats 2 below the brush 1C. Between these two brushes 1C, the negative polarity ID is connected to a second secondary winding 4B with a middle terminal which is connected to the DC negative polarity supply terminal! four-pole rotary machine.

If one single-phase transformer is used instead of two single-phase transformers, one single-phase transformer must have the same power as the two transformers together.

The function of the device according to the invention is as follows: a DC anchor current I, based, for example, on the motor from the positive polarity supply terminal, enters the middle terminal of the first secondary winding 4A, divided into two components, each of ~ each half of the first secondary winding 4A, so that their magnetic voltages cancel each other out and the transformer is therefore not pre-magnetized by direct current, which is a condition for its proper functioning. Thus, each of the positive polarity brushes ΙΑ, IB is loaded with a half value of the DC anchor current I, as is the case with a DC rotating machine without using the subject matter of the invention. In the magnetic symmetry of a DC rotating machine, no direct current is passed through the first eiquipotential couplings 3A. Once the primary winding of the single-phase transformer has been connected to the low-voltage single-phase network when the DC anchorage current I falls below 3C% of the nominal value by an unconstrained automatics, the additional alternating current I ~ of the first secondary winding 4A flows through both positive polarity brushes. 3A between the first and second positive polarity brushes 1B are connected in parallel to each other, when the two commutator slats are covered with the positive polarity brushes 1A, 1B, an additional AC current of - -

This is advantageous since the first equipotential couplings 3A are then thermally advantageously stressed, while the additional alternating current I pod under both positive polarity brushes jeA, 1B is larger and easily completes half the DC anchor current I to over 30% of half the nominal DC because the impedance of the first equipotential couplings 3A is slight compared to the impedance of the anchor winding between the positive-polarity brushes ΙΑ, 1B, the additional alternating currents I ~ will be closed over the first equipotential couplers. 3A. On the other hand, the impedance of the anchor winding is between. of positive polarity brushes ΙΑ, 1B due to the prevailing reactance of a large number of coils of the anchor winding which are housed in the grooves of the rotor body.

Similar conditions apply to both negative polarity ID brushes 1C, but only with the reverse direction of the DC anchor current I entering the negative polarity power supply terminal of the DC quadrupole rotating machine.

Claims (1)

Subject A device for reducing brush and commutator wear of a DC · 4-pole rotary machine with parallel anchor winding and equipotential couplings, characterized in that two secondary windings (1C, ID) are connected to two negative polarity brushes (ΊΑ, 1B). (4A, 4B) of a single-phase transformer or two single-phase transformers, respectively, so that two positive polarity brushes (TA, 1B) are connected to the first of the invention of a cundary winding (4A) having a middle terminal connected to the positive polarity DC power terminal A second secondary winding (4B) is also connected to the two negative polarity brushes (TC, ID), which is also provided with a central terminal coupled to the negative polarity power supply terminal of the DC four-pole rotary machine.