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Earth Return Current Units – Ground brush

Earth Return Current Units – Ground brush

Overview

 
Axial Earth Return Current Units (ERCU) on bogie for high speed train

In 1968, Mersen have invented this system which offers 3 mains functions. The first function is to prevent the passage of current through the axle boxes (bearings).

The flow of electric current through the axle box roller bearing of railway vehicles is one major problems for the safety and reliability of rolling stock.

It is necessary to use devices shunting the greatest part of the current through the axles and wheels without flowing through the roller bearings.

The second function is to insure rails equipotentiality.

The third function is to Transmit Trains signal detection between 2 rails portions for each districts.

An additional function can be integrated in the ERCU is the pulse generation with a dented wheel.


 

Benefits

 
Axial Earth Return Current Units (ERCU) on bogie for intercity train

Uses of ERCU Ground brush

The benefit of using the ERCU from Mersen is to benefit of the design of the company which have created this device using its own impregnated graphite brushes.

Mersen strongly recommend to use Mersen carbon brushes, specially designed for ground brushes Mersen.

Mersen recommends to use Mersen brushes, specially designed for Mersen ERCU.

Brushes are made of an agglomerated mix of copper and graphite powders. The copper percentage is high in the to give a low electrical resistance and the ability to the brushes to carry up to  25 A/ cm², without any damage for the contact disc.

Contact discs are made in a special bronze.

ERCU performances are obtained only with this type of brush.

 

  Section Courant Nominal Courant crête Courant 100ms
  Cm2 A kA kA
3 balais 20x40 24 600 27 10
3 balais 12,5x32 12 300 19 7
2 balais 20x25 10 260 16 6
2 balais 16x25 8 200 12 5
1 balais 10x25 2.5 65 5.5 2

 
One flexible cable and one black cable and hardware

Spare part kits

Mersen will supply you all Spare parts kits to guarantee the reliability and increase the life time of your product.

  • Brushes,
  • Connection Cables and braided cables
  • adapted cable support
  • Covers and frames
  • Gaskets, hard ware and all necessary components

    Metro workshop station Current Collector Device (CCD) work shop training

    Training and assistance

    Mersen Design team is available to support your design and maintenance team’s especially for the smart and connected functions.

    Mersen Service team can train your Maintenance team to make the setting and the maintenance of your installations all around the world.

     

    Show less
     
    Axial Earth Return Current Units (ERCU) on bogie for intercity train

    Uses of ERCU Ground brush

    The benefit of using the ERCU from Mersen is to benefit of the design of the company which have created this device using its own impregnated graphite brushes.

    Mersen strongly recommend to use Mersen carbon brushes, specially designed for ground brushes Mersen.

    Mersen recommends to use Mersen brushes, specially designed for Mersen ERCU.

    Brushes are made of an agglomerated mix of copper and graphite powders. The copper percentage is high in the to give a low electrical resistance and the ability to the brushes to carry up to  25 A/ cm², without any damage for the contact disc.

    Contact discs are made in a special bronze.

    ERCU performances are obtained only with this type of brush.

     

    Show more

    Capabilities

    Open Axial Earth Return Current Units (ERCU) showing the 3 brushes.

    Cost efficient, reliable and secure

    The range of Mersen is showing the following possibilities and characteristics:

    • Axial (Axel end), Radial or into the wheel position
    • Current from 200 to 800 Amp
    • Speed > 200km/h
    • Low contact resistance (5 moHms)
    • 1 to 4 brushes (12,5x32; 16x25; 20x25; 20x40; 25x50mm)
    • With or w/o Contact Disc
    • Possibility adapt connexion plates
    • Possibility to paint them
    • Include a Speed sensor (pulse generator)
    • Low maintenance and Fast and Easy brush replacement

    They are build for the life time of the train and only the brushes have to be changed periodically.

     


     

    Design Guide

     
    Earth Return Current Units (ERCU) 2 Gaines ERCU into isolated wheel Axial low floor tramway
    Radial Earth Return Current Units (ERCU) on bogie

    Configuration

    Three configurations are possible depending of the application (Train, Tramway or Metro)

    • Axial or axel end for trains and Metro
    • Radial or top for trains and Metro and
    • Into the wheel for low floor tramways

     


    Current range

    Depending of the number and the size of the impregnated carbon brushes, the ERCU range covers from 200 to 800 Amp with ERCU equipped with 1 to 4 brushes (12,5x32; 16x25; 20x25; 20x40; 25x50mm).

     


    Short time withstand current

    Short time withstand current 100ms can go up-to 7kAmp

    Short time peak withstand current can go up-to 19kAmp.

     


    IP protection

    The range offers IP 547 as basic protection but adding some gaskets, some ERCU can offer IP56.

     


    Material used

    Material of body = Stainless Bronze, connection tinned

    Material of cover = 3 mm thick zinc plated (15 microns) steel cover plate, Aluminium Alloy,

    Brass or Stainless steel

    Material of spring and screws = stainless steel

    Material of insulating ring = Compound polyester 

     


    Open Axial Earth Return Current Units (ERCU) to be used with pulse generator or speed sensor

    Pulse generator or speed sensor

    An angular speed sensor is mounted on the ERCU and transmits to an electronic system that can:

    • Detect when a wheel slips to control traction or engine speed, or to trigger an anti-skid system.
    • Detect whether the train is running or stopped, in order to trip or release safety systems such as door locks.
    • Detect which way the train is traveling.

    Mersen do not provide the sensor itself but prepare a space to install it.

     


     
    partial view of 4 different Earth Return Current Units (ERCU) to show different cable connections

    Cable connections

    Connexion plate can be designed for “external” or “internal” connexions to
    meet your requirements. Also the cover of the ERCU can be electrically isolated.

     


    Earth Return Current Units (ERCU) painted cover black service

    Painted cover

    Mersen can supply the covers painted in relation with the colour of the train.

     


     
    Earth Return Current Units (ERCU) cover cataphoresis coating to protect against salt mist service

    Cataphoresis protection

    Mersen propose a cataphoresis coating of the cover for a protection to 1000h to salty mist test.

     


     
    Axial Earth Return Current Units (ERCU) 2 slip discs

    Slip discs

    The slip disc is the component fixed on the wheel on which the brushes are in contact to pass the current.

     


     
    Earth Return Current Units (ERCU) detailed view of engraved identification QR code

    Identification

    Each ERCU is identified with a lot number but Mersen can also add QR code.

     


    Tooling

    Beside the spare parts, Mersen can supply the necessary tooling to set perfectly your equipment to the technical requirements of your network and optimize their use.

     


     
    Illustration of an equation on paper and pen

    LCC; RAMS; Type tests

    Mersen team provide type test and different studies (Life Cycle Cost, RAMS, FMEA, Eco Design and recyclability, etc…) to secure the reliability of your equipment and its conformity to standards and legislations.


     

    Show less
     
    Earth Return Current Units (ERCU) 2 Gaines ERCU into isolated wheel Axial low floor tramway
    Radial Earth Return Current Units (ERCU) on bogie

    Configuration

    Three configurations are possible depending of the application (Train, Tramway or Metro)

    • Axial or axel end for trains and Metro
    • Radial or top for trains and Metro and
    • Into the wheel for low floor tramways

     


    Current range

    Depending of the number and the size of the impregnated carbon brushes, the ERCU range covers from 200 to 800 Amp with ERCU equipped with 1 to 4 brushes (12,5x32; 16x25; 20x25; 20x40; 25x50mm).

     


    Short time withstand current

    Short time withstand current 100ms can go up-to 7kAmp

    Short time peak withstand current can go up-to 19kAmp.

     

    Show more

    Earth Return Current Units – Ground brush range

    Axial ERCU

    • 300 Amp 3G 12,5x32
    • 600 Amp 3G 20x40
    • 800 Amp 4G 20x40

     

    Radial ERCU

    • 250 Amp 2G 20x25
    • 400 Amp 2G 20 x40
    • 625 Amp 2G 20 x50

     

    Into the wheel

    • 200 Amp 2G 16x25

    • 300 Amp 4G 12,5 x25

    Completed Projects

    SNCF (FR), British Rail (GB), Deutsch Bahn (DE), Eurotunnel (FR), ONCF (MA), SATS (ZA), AMTRAK (US), RENFE (ES), SNCB (BE), NS (NL), China (CN), Japan (JP), Roma (IT), Cairo (EG) Kochi (IN) 

    Documents & Resources

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