AC Coaches:

Types of AC coaches:

  • Self-generating –Conventional & RMPU type
  • EOG –Conventional & RMPU type
SG(Self generating):
  • Power supply for AC equipments is met from axle driven transom mounted brushless alternator rated 110v DC supply.
Equipments:
  • 2*18 kw alternator running at>MFO 800Ah cells,
  • 200A cap battery charge,
  • 415v, 50Hz, 3 phases pre-cooling plug-2 no’s,
  • RRU- 18 kw at 130 V
EOG (End-on-generation):

The power supply is derived from DG set 415V/750v, 3phases, 50 Hz. Power is distributed to entire rake through 2 sets of 3 phase, 415/750v feeders. Each coach is provided with control, distribution and feeder arrangement on the control panel. The AC equipment works on 415 v supply and lighting equipment on 110 v AC obtained from 3KVA, 415/190 V, 4 wire step down transformer.

The drawback of conventional type AC coaches:
  • It has open type of compressor system, so
  • More spacious, heavyweight, more maintenance cost.
  • More leakage problem from pipes and joints.
  • More manpower required.
  • Consuming more, less energy efficient.
Features of RMPU type AC coaches:
  • Light in weight
  • Low cost of installation
  • No water leakage
  • Hermetically sealed compressor, so no outside fittings.
  • Use of 3 phase induction motor, less maintenance cost.
  • No change of damage by CRO and flash flood etc.
  • More energy efficient, modern technology and excellent performance.
  • Prevention of fire on SG coaches:
Excessive current:

This is the only [probable cause of electrical fires on coaches due to inadequate size of cables or any short circuit. Size of cables on the different circuit has been standardized as per specification –EL/TL/48.

Protective devices:

The short circuit is the only cause of the Electrical fire. So, HRC fuse/ re-wirable fuse have been standardized and HRC/ re-wirable fuse shall be procured from RDSO approved source only.

Segregation of (+) & (-) cables:
  • All wires shall be segregated by running them in 2 separate conduits.
  • Prevention of fire on AC coaches
Excessive current:

This is the only probable cause of electrical fires on coaches due to inadequate size of cable or any short circuit. Sizes of cables on different circuits have been standardized.

Protective devices:

The short circuit is the only cause of the Electrical fire. So, HRC fuse/ re-wirable fuse have been standardized and HRC/ re-wirable fuse shall be procured from RDSO approved source only.

Segregation of (+) & (-) cables:

The wiring on U/F and end walls of the coaches shall be run in rigid steel conduit whereas on the superstructure the cables shall be run in rigid/flexible PVC conduits. The (+) and (-) cables shall be segregated by running them in two separate conduits. Cable from alternator to underframe terminal board, under frame terminal board to RRU, RRU to battery is run in steel reinforced vinyl flexible hose (k1 of Finolex)