AC COACHES SYSTEM

AC COACHES

Types of AC coaches

• Self generated- 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 X 18 kw alternator running at > MFO
• 800 Ah cells,
• 200A cap battery charger,
• 415 v, 50 Hz, 3 phase pre-cooling plug- 2 nos,
• RRU- 18 kw at 130V

EOG (End-on – generation)
Power supply is derived from DG set 415 V/ 750v, 3 phase, 50 Hz. Power is distributed to entire rake through 2 sets of 3 phase, 415/ 750 v feeders. Each coach is provided with control, distribution and feeder arrangement on control panel. The AC equipments works on 415 v supply and lighting equipment on 110 v AC obtained from 3 KVA, 415 / 190 V, 4 wire step down transformer.
Drawback of conventional type AC coaches:
It has open type of compressor system, so…

• More spacious, heavy weight, more maintenance cost.
• More leakage problem from pipes and joints.
• More man power 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 out side fittings.
• Use of 3 phase induction motor, less maintenance cost.
• No chance of damage by CRO and flash flood etc.
• More energy efficient, modern technology and excellent performance.

Comparison of RMPU with conventional AC coach

SN	Description	Roof mounted	Conventional
1	weight	900 kg	2700 kg
2	Installation time	4 hrs	4 days *
3	Refrigerant	F-22 (CHCl F 2)	F-12 (CCl 2 F 2)
4	Refrigeration charge	< 3 kg	15 – 20 kg
5	System design	Hermitically sealed	Open
6	Refrigerant leak potential	Nil	Enormous
7	Maintenance	little	Heavy
8	Dust collection	little	Heavy
9	Damage due to CRO	NIL	Heavy
10	Damage due to flash flood	NIL	Heavy
11	Performance	Excellent	Deteriorates quickly due to dust collection.
12	Technology	latest	Old and absolute.
13	Water drop on passenger	NIL	sometimes
14	Fresh air	Taken from roof	Taken from side wall of toilet
15	Capacity control	25% to 100% (4 compressors)	50% to 100% (2 compressors)
16	Down time for repair	4 hrs (for replacement of RMPU)	4 days (depends upon the equipment failed)
17	Motor used	3 phase I.M.	DC motor
18	Tones	7.0 x 2	5.2 X 2
19	Energy consumption	less	More
20	Humidity control	By microprocessor based controlling system	Old conventional method