JPS60249848A - Wear limit detector of brush of induction machine - Google Patents

Abstract

PURPOSE:To provide safety by mounting a detector at the end of an insulating support which rotates upon wearing of a brush, and installing a detecting element for detecting the approach of the detector at the prescribed position, thereby separating the detector and the element from the high voltage of the brush. CONSTITUTION:A brush 4 is mounted at one end of an insulating supporting rod 7 at a brush retainer 6 to press the periphery of a slip ring, a metal detector 8 is secured to the end, and the detector 8 rotates in a direction of an arrow upon wearing of the brush 4. A detecting element 9 for generating an electric signal when the detector 8 is rotated to the predetermined position is disposed at the stationary section of an induction machine. Thus, since the detector 8 and the element 9 can be separated from the high voltage section, the insulating reliability increases to protect signal communication means against an induction defect due to a rotor current.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field to which the Invention Pertains) The present invention relates to a wear limit detection device for rotor coil excitation brushes that utilizes a brush holder for a wound induction machine. In this scale device, it is necessary to accurately detect when the brush has reached its wear limit, and in this case, it is configured to be able to remotely receive the signal detected by the brush wear limit detection element of the device. is most desirable.

(Prior art and its problems) In the case of electric machines that are generally used in areas that are not regularly inspected by security personnel or areas that are difficult to access at all times even if they are inspected,
Particularly in induction machines that frequently start and stop or whose speed is controlled by external resistance, it is possible to prevent unexpected accidents due to wear by taking necessary measures for parts that are extremely susceptible to wear, namely the excitation brush. It is necessary to take some means to accurately detect the wear limit of the brush and communicate it to a predetermined location. A detection element placed close to and facing a metal detection piece installed on the head of the brush, for example, detects the amount of movement of the detection piece that moves as the brush wears, and detects the brush wear limit. A device that detects brush wear and sends a signal by installing a detection piece directly on the brush body, such as the brush wear detection device for rotating electric machines (utility model application published in 1982-29405), is designed to detect brush wear and send a signal. If the voltage and voltage applied to the sensor are normally not that high, the insulation of the sensing element and other open cavities are not required.Providing a sensing piece will not only cause problems with the insulation of the sensing elements that are placed close to each other, but also cause damage to the rotor circuit. Since there is a risk of induction failure in the detection element or communication means due to alternating current lightning or magnetic induction, and it is difficult to ensure accuracy in the detection operation, another means is provided in the configuration of the brush wear limit detection device.
It is necessary to do y.

(Object of the Invention) The present invention addresses the above-mentioned drawbacks of conventional brush wear detection devices in which the detection body is provided directly on the brush body in the case of induction machines, particularly high-pressure induction machines. It is an object of the present invention to provide a brush wear limit detection device in which the elements and communication means are provided at a required distance from the brush and are safe with respect to insulation against brush voltage and induced disturbances due to rotor circuit current.

(Key Points of the Invention) An insulating support rod whose one end is fixed to the plan holder of a brush holder of a wound wire induction machine and rotates together with the brush holder as the brush wears; and an insulating support rod attached to the tip of the support rod. It consists of a metal detection body and a detection element placed on a fixed part of the induction machine to detect the approach of the detection body, and when the detection body reaches a predetermined position by rotation of the support rod, the It is designed to transmit an electrical signal from the detection element.

(Examples of the Invention) Next, details of the present invention will be explained based on embodiments of the invention shown in the drawings.

A pair of current collecting bridges 2 supported by a fixed part of the induction machine are disposed for each slip ring along the outer periphery of a predetermined number of slip rings 1 fixed to the rotor shaft 10 in the first V. A required number of brush holders 11 are mounted on the bridge 2, and the brushes 4 are inserted and held in the square through holes of the brush holder box 3 of the brush holders 11.

Further, as shown in FIG. 2, the brush holder 6 supported by a pin 12 provided at one end of the brush holding box 3 is provided with a arm 6a at one end that directly contacts the upper end of the brush 4, and the lower end of the brush holding box 3 is A spring 15 held by a pin 13 provided at the upper end of the brush holder 6 and a pin 14 provided at the upper end of the brush holder 6 allows the arm 15 to maintain an appropriate surface pressure at all times on the contact surface between the brush 4 and the slip ring 1. The tip of 6σ2 presses the brush 4.

Further, as shown in FIG. 3, a support rod 7 made of an insulating material is connected to the side surface of the brush holder 6 of one brush holder 11 of the plurality of brush holders, and a support rod 7 made of an insulating material is connected to the side surface of the brush holder 11 of the plurality of brush holders. An iron piece 8 is placed as a detection object at the tip of the support rod at a distance that does not receive electromagnetic induction due to the alternating current of the sub-circuit.
to be fixed.

In the brush holding h 11 configured as described above,
As the brush 4 wears out due to mutual friction as the slip ring rotates, the arm 6α of the brush holder 6 also follows the brush 4 and moves in the direction indicated by the arrow in FIG. 2 around the pin 14. do. As a result, the support rod 7 connected to the side surface of the brush holder 6 also rotates in the same direction as the brush holder 6. Therefore, if a proximity switch 9 is provided in advance by appropriate means at the position occupied by the detection body 8 fixed to the tip of the support rod 7 when the brush 4 reaches its wear limit, the proximity switch 9 will be the detection body. Actuated by the iron piece 8, it emits an electrical signal so that a suitable receiver detects that the brush 4 has reached its wear limit. In a normal induction machine, the brush wear is almost uniform in all brush holders, so all brushes are replaced at the same time based on the results detected by the brush holder's brush wear limit detection device. There is no problem.

Further, as described above, the detection body 8 is fixed to the insulating support rod 7 with a necessary spacing between it and the brush holder 11, and therefore the proximity switch 9 is also fixed with a necessary spacing between it and the brush holder. However, there are no problems with the insulation of the proximity switch and the isolation of the signal communication means from inductive disturbances.

(Effects of the Invention) As described above, the present invention provides a rotor coil excitation brush wear limit detection device that uses a brush holder of a wound induction machine, in which one end is fixed to the brush holder of the brush holder. A metal detection body attached to the tip of an insulating support rod having a required length and rotating together with the brush holder as the brush wears out; A brush wear limit detection device of an induction machine is constructed from a detection element which is arranged and transmits an electric signal when the detection body reaches a predetermined position due to rotation of the support rod, and the brush wear limit is detected. Since the detection element can be placed sufficiently apart from the brush holder, it is possible to insulate the detection element from the high voltage of the rotor circuit and to protect the signal communication means from induction disturbances caused by rotor current using an extremely simple and inexpensive device. There are benefits to be gained.

[Brief explanation of drawings]

FIG. 1 is a front view showing the arrangement of a brush holder related to the brush wear limit detection device of the present invention, and FIG. FIG. 3 shows a front view and a side view, respectively, showing the mutual positions of the feeder and the detection element of the brush wear limit detection device of the present invention with respect to the brush holder. 4: brush, 6: brush holder, 6α: armrest, 7: insulating support rod, 8: detection object, 9: detection element, 11: brush holder. Figure 1 Figure 3

Claims (1)

[Claims] 1) In a device that detects the wear limit of a rotor coil excitation brush through a detection body attached to a brush holder of a wound type induction machine, one end is fixed to the brush holder of the brush holder to prevent wear of the brush. An insulating support rod that rotates together with the brush holder, a metal detection object attached to the tip of the support rod, and a detection element arranged on a fixed part of the induction machine to detect the approach of the detection object. A brush wear limit detection device for an induction machine, characterized in that when the detection body reaches a predetermined position due to rotation of the support rod, an electric signal is transmitted from the detection element. .