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Electrical Protection System -Train Lighting and Air Condtioning

By on May 11, 2013

110V system is used for train lighting with floating potential. Positive and negative circuit runs separately on two different side panels of the coach and comes together only near lamp, fan and switch. A fault in one wire will not cause any problem but as soon as there is occurrence of another fault, fault current starts flowing through alternate unintended path. 110 V system is not dangerous to human beings but can be a major cause of fire arising due to spark or overheating if protection also does not work. Following precautions are taken to protect from fire and faults:

  • System design with reliability features such as rating of wire, HRC fuse, location, securing of wire, system of tightness at joints, use of only non-flammable materials particularly in the vicinity of electrical joints etc.
  • Provision of primary,  secondary and tertiary fuse protection
    • Re-wirable 6 A fuse wire on both positive and negative side at the panel board in individual cabin for lights and fans.
    • 16A, 3 nos. HRC fuse in each coach at positive and negative wire
    • 40 A HRC fuse at positive and negative battery terminal.This ensures no wire left unprotected.
    • During maintenance negative bonding is checked wherein a lamp is connected alternately between positive and negative terminal with earth. In case lamp glows, earth fault is suspected.
    • Carbon dust contributes significantly towards to negative bonding in DC fan.
    • GS coaches are generally overcrowded and passenger sitting on upper berth does not find opportunity to get down. Released cigarette/biri, pan masala pouches or any other waste finds way into cabin terminal board becoming dangerous to fire.  Special care during design and maintenance is being taken. BEML is providing flushed inspection cover as shown in the picture above where there is no possibility to insert any foreign body inside.

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