EP0113836A2 - Dispositif pour contrôler l'usure des balais - Google Patents

Dispositif pour contrôler l'usure des balais Download PDF

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Publication number
EP0113836A2
EP0113836A2 EP19830111819 EP83111819A EP0113836A2 EP 0113836 A2 EP0113836 A2 EP 0113836A2 EP 19830111819 EP19830111819 EP 19830111819 EP 83111819 A EP83111819 A EP 83111819A EP 0113836 A2 EP0113836 A2 EP 0113836A2
Authority
EP
European Patent Office
Prior art keywords
reed switch
brush
screen
magnet
carbon brush
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19830111819
Other languages
German (de)
English (en)
Inventor
Helmut Dipl.-Ing. Kinzel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BBC Brown Boveri AG Germany
Original Assignee
BBC Brown Boveri AG Germany
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BBC Brown Boveri AG Germany filed Critical BBC Brown Boveri AG Germany
Publication of EP0113836A2 publication Critical patent/EP0113836A2/fr
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R39/00—Rotary current collectors, distributors or interrupters
    • H01R39/02—Details for dynamo electric machines
    • H01R39/58—Means structurally associated with the current collector for indicating condition thereof, e.g. for indicating brush wear

Definitions

  • the invention relates to a device for monitoring the brush wear of carbon brushes guided in brush holders and pressed under spring pressure on a commutator or slip ring of an electrical machine.
  • Brush monitoring is required to prevent the collector from being damaged by premature wear of a carbon brush in commutator or slip ring machines, which would lead to failure of the electrical machine. Monitoring by regular inspection takes a lot of time and is often made difficult, if not impossible, by poor access to the power supply.
  • Switch-off devices for carbon brushes have therefore become known (EP 23 537), in which brush wear is interrupted by a stop when the brush has reached its minimum permissible length.
  • the contact between the brush and the commutator or the slip ring is interrupted, so that arcing can occur. Such an arc can destroy the brush holder and damage the commutator.
  • the signaling circuit contains two signaling contacts, which are insulated from the brush holder and the carbon brushes and which are short-circuited or opened depending on the state of wear of the carbon brush.
  • a disadvantage here is the sensitivity of the signaling contacts to dust, corrosion and oxidation, which cannot always guarantee reliable monitoring even over long periods of time.
  • the object of the invention is to provide a device for monitoring brush wear according to the preamble of claim 1, which avoids the disadvantages mentioned. It should enable automatic monitoring of carbon brush wear even during the operation of the electrical machine and be decoupled from the voltage potential of the commutation or the slip ring.
  • the device should also be characterized by a simple, robust structure, be easily integrated into the construction of brush holder carriers and, if necessary, a retrofit Allow electrical machines to be equipped with brush monitoring. Finally, the device should ensure reliable monitoring of brush wear even over long periods of time and be insensitive to dust, corrosion and the like.
  • At least one ferromagnetic shield is provided which is in mechanical contact with a carbon brush and which is pushed so far between a magnet and a reed switch for a given wear length of the carbon brush that due to the weakening of the magnetic field in the reed switch a switching process is triggered.
  • Such reed switches are known. They generally consist of contact tongues of ferromagnetic material which are melted into a glass tube and which, under the influence of a magnetic field, assume opposite polarity and attract each other with sufficient magnetic force flow, as a result of which electrical contacts are closed or opened.
  • the contacts can be connected to signal output devices and control devices and trigger warning signals or control functions (e.g. switching off the machine) if the carbon brush is less than the worn length.
  • the brush monitoring is not sensitive to dust, corrosion and oxidation. Furthermore, the monitoring works according to the normally closed contact principle and responds not only when the remaining brush length falls below an arbitrary value, but also when the magnet and reed switch arrangement is damaged and when the magnetic flux fails or decreases due to damage or aging of the magnet.
  • the front according to the invention direction enables reliable, automatic brush monitoring even after long periods of operation and thus particularly fulfills the requirements for use in mass production.
  • An advantageous embodiment of the invention provides that the screen is mechanically coupled to the mechanism that serves to press the carbon brush onto the commutator or slip ring. This arrangement enables easy installation of the brush monitoring device and allows a problem-free carbon brush change without dismantling the monitoring device.
  • a translational movement of the carbon brush due to its wear is advantageously transmitted to the screen in such a way that it carries out a translatory movement or a rotary movement and is thereby pushed between the magnet and the reed switch.
  • a particularly advantageous embodiment of the invention results when the magnet and reed switch are embedded in a component made of potting compound, which contains a slot between the magnet and reed switch through which the shield can be inserted. Such an embodiment significantly reduces the manufacturing and assembly costs.
  • the arrangement of the magnet and reed switch can be shielded by a ferromagnetic encapsulation.
  • the monitoring device is designed as a kit in which, for example, the scanning sensor, the transmission mechanism, the screen and the magnetic reed switch arrangement are preassembled and in the area of the brush or on Brush holders can be fastened in such a way that the scanning sensor rests on the brush.
  • the displacement of the brush within the brush holder due to brush wear is transmitted to the screen by means of the transmission mechanism and triggers a switching operation of the reed switch at a predetermined presetting.
  • Such pre-assembled kits can be manufactured at low cost and used in a variety of ways.
  • the reed switch has a contact pair with two electrical connections, the contact pair being closed under the action of a magnetic field.
  • the magnetic field is weakened by the screen in such a way that the contact pair in the reed switch is opened and a circuit is interrupted.
  • Such a circuit arrangement is advantageous because other interferences, e.g. Open circuit of the reed switch leads, trigger an interference signal or the like.
  • the invention can also be developed such that the reed switch has a contact pair with two electrical connections and that the contact pair is opened under the action of a magnetic field.
  • a device designed in this way can directly switch on a signaling device located in a signaling circuit, for example a lamp, if the length of the brushes falls below a predetermined length becomes.
  • the invention can be further developed such that one of the two electrical connections of the reed switch is connected to the housing of the electrical machine and the other electrical connection is connected to a monitoring device via a signal line.
  • This solution is particularly useful when both the electrical housing of the electrical machine and the monitoring device are at the same ground potential.
  • the reed switch contains at least one changeover switch with three electrical connections, in which a changeover of a first connection from a second connection to a third connection takes place when a magnetic field threshold value is exceeded or fallen below.
  • a connection can optionally be connected to the housing of the electrical machine.
  • FIG. 1 and 2 show a brush holder 10, in which two carbon brushes 11 are inserted, which grind with their running surfaces on the commutator 12 of an electrical machine (not shown further).
  • a current-carrying wire 13 is connected to each carbon brush 11 and carries a cable lug 14 at its free end.
  • the cable lugs 14 of the two carbon brushes 11 are electrically connected to a contact plate 16 by screws 15.
  • the contact plate 16 is in turn, which was not shown in the drawing, connected to an electrical lead of the electrical machine.
  • one of the two brackets 18 carries a sheet-metal part designated with a screen 24.
  • the screen 24 is made of ferromagnetic material and is rigidly connected to the bracket 18 so that it is pivoted in the direction of arrow 25 when the carbon brush 11 is worn. With advanced wear of the carbon brush 11 up to a predeterminable remaining brush length, the screen 24 enters the slot 26 of a component 27 made of potting compound.
  • a permanent magnet 28 and a reed switch 29 are cast into the component 27 on both sides of the slot 26.
  • the field strength of the permanent magnet 28 and the arrangement between the permanent magnet 28 and the reed switch 29 are selected so that the contact tongues of the reed switch 29, not shown, attract each other and the two leads 30, 31 of the reed switch 29 are electrically short-circuited.
  • the magnetic field of the permanent magnet 28 in the area of the reed switch 29 is weakened in such a way that the attracting ones. Relieve the forces of the contact tongues and spring them back to their original position. The contact point is opened so that the leads 30, 31 are electrically isolated.
  • the component 27 can, which has not been shown, e.g. be attached to the brush holder 10 or at a suitable location on the machine housing.
  • the position in which the component 27 is fastened depends on the predeterminable remaining brush length at which the switching function of the reed switch 29 is to take place.
  • the component 27 is shown in perspective and schematic representation in FIGS. 3 and 4 and in FIG. 5 in shown a side view.
  • the component 27 is U-shaped, so that a slot 26 is formed between two legs.
  • a permanent magnet 28 is embedded in one leg (according to FIGS. 3 and 4 in the front leg). This permanent magnet 28 is opposite a reed switch 29 embedded in the other leg, of which only a feed line 30 can be seen in FIGS. 3 and 4.
  • a sheet-shaped shield 24 made of ferromagnetic material can be pivoted into the slot 26.
  • wear of the carbon brush can be converted into a translational movement 32 of the screen 24, the screen 24 being connected via a lever 33 to a transmission mechanism, not shown.
  • the carbon brush wear can also be converted into a rotary movement 45 of the screen 24 according to FIG. 4.
  • the screen 24 can be mounted in an axis of rotation 35 and moved by a transmission mechanism (not shown) via a drive rod 36.
  • a similar embodiment has already been described with reference to FIG. 1.
  • the reed switch 37 shown contains two contact tongues 38, 39 made of ferromagnetic material and a fixed non-magnetic contact 40.
  • a contact tongue 38 is connected to ground 46 (eg the machine housing).
  • the other contact tongue 39 leads to an earthed monitoring device 41 (not described in more detail).
  • the contact 40 is connected to ground via a series connection of a lamp 42 and a voltage source 43.
  • the operation of this circuit arrangement is as follows: When the electrical machine is not disturbed, the reed switch 37 is fully exposed to the magnetic field of the permanent magnet.
  • the contact tongues 38, 39 assume an opposite polarity and, as shown, attract each other and make a contact.
  • the input 44 of the monitoring device 41 is thus at ground 46.
  • the contact tongue 38 springs back into its rest position and makes electrical contact with the contact 40. This closes a circuit in which the lamp 42 and the voltage source 43 are located, and the lamp lights up.
  • the monitoring signals can be interpreted as follows: The lamp 42 only lights up when the critical brush length is not reached. Furthermore, the input signal 44 of the monitoring device 41 is only at ground potential if the critical brush remaining length has not yet fallen below.
  • monitoring devices 41 can be used to evaluate the switching state of the reed switch 37.
  • monitoring devices can be used that emit acoustic or optical signals.
  • Monitoring devices can also be used, which perform switching functions and, for example, switch off the electrical machine as soon as the switching position of the reed switch 37 indicates burnt-out carbon brushes.

Landscapes

  • Motor Or Generator Current Collectors (AREA)
EP19830111819 1982-12-21 1983-11-25 Dispositif pour contrôler l'usure des balais Withdrawn EP0113836A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19823247330 DE3247330A1 (de) 1982-12-21 1982-12-21 Vorrichtung zur ueberwachung der buerstenabnutzung
DE3247330 1982-12-21

Publications (1)

Publication Number Publication Date
EP0113836A2 true EP0113836A2 (fr) 1984-07-25

Family

ID=6181303

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19830111819 Withdrawn EP0113836A2 (fr) 1982-12-21 1983-11-25 Dispositif pour contrôler l'usure des balais

Country Status (2)

Country Link
EP (1) EP0113836A2 (fr)
DE (1) DE3247330A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2172445A (en) * 1985-03-15 1986-09-17 Heidelberger Druckmasch Ag Device for indicating the condition of an electric motor brush
EP0268010A1 (fr) * 1986-10-23 1988-05-25 G. Dietrich GmbH Spezialfabrik für Bürstenhalter und Kunststoffteile Porte balais avec indicateur d'usure de ces balais
FR2613546A1 (fr) * 1987-04-03 1988-10-07 Ferraz Porte-balais pour machines electriques
CN105333807A (zh) * 2015-11-20 2016-02-17 中国华能集团清洁能源技术研究院有限公司 发电机监测系统
CN104868662B (zh) * 2015-05-29 2017-04-12 江苏云意电气股份有限公司 一种碳刷安装方向防错治具

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3504881A1 (de) * 1985-02-13 1986-08-14 Anton Piller GmbH & Co KG, 3360 Osterode Buerstenhalter fuer elektrische maschinen mit im halter beweglicher schleifbuerste
DE102011005302B4 (de) * 2011-03-09 2012-10-31 Schunk Bahn- Und Industrietechnik Gmbh Verschleißerkennungssystem und Verfahren

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1488837A (en) * 1974-06-03 1977-10-12 Fisons Ltd Brushgear for electric motors
DE2527303A1 (de) * 1975-06-19 1977-01-13 Piller Kg Anton Vorrichtung zur ueberwachung der abnutzung der buersten von elektrischen maschinen

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2172445A (en) * 1985-03-15 1986-09-17 Heidelberger Druckmasch Ag Device for indicating the condition of an electric motor brush
GB2172445B (en) * 1985-03-15 1989-04-19 Heidelberger Druckmasch Ag Device for indicating the condition of a brush on a drive motor in particular on a drive motor of a printing press
EP0268010A1 (fr) * 1986-10-23 1988-05-25 G. Dietrich GmbH Spezialfabrik für Bürstenhalter und Kunststoffteile Porte balais avec indicateur d'usure de ces balais
FR2613546A1 (fr) * 1987-04-03 1988-10-07 Ferraz Porte-balais pour machines electriques
CN104868662B (zh) * 2015-05-29 2017-04-12 江苏云意电气股份有限公司 一种碳刷安装方向防错治具
CN105333807A (zh) * 2015-11-20 2016-02-17 中国华能集团清洁能源技术研究院有限公司 发电机监测系统

Also Published As

Publication number Publication date
DE3247330A1 (de) 1984-06-28

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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AK Designated contracting states

Designated state(s): BE DE FR GB IT NL SE

STAA Information on the status of an ep patent application or granted ep patent

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18D Application deemed to be withdrawn

Effective date: 19860603

RIN1 Information on inventor provided before grant (corrected)

Inventor name: KINZEL, HELMUT, DIPL.-ING.