POWER SUPPLY IN A/C COACHES The power supply technology used in train interiors have indirect coupling with axle. This makes system lesser efficient and bulky. Magnets mounted on axles with stator of slotted hollow cylinder will make alternator that will be robust and light weight. This cheaper system will be simple and easy to use.

CONTINUED… The output voltage from alternator will have many frequencies.Hence we will pass it through converter cum regulator insuring total elimination of harmonics. The pure DC output from it will be feed to batteries and supply.

AUTOMATIC FEEDBACK CONTROL SYSTEM It is a feedback system because rotational energy is output of train while it is input for alternator and output of alternator, electricity is again transferred to power supply system of train. The production of electricity from this system is also at the time of breaking. Trains have very fluctuating speed hence this electricity produced will also be fluctuating in nature so we cannot feed this to supply directly.

AUTOMATIC POWER FACTOR CORRECTION SYSTEM

APFC The controller continuously senses the instantaneous magnitude and direction of the reactive power demand through line Current Transformer (CT) and Potential Transformer (PT). It generates a signal for switching and turns the capacitor bank on & off to provide the necessary reactive power (kVAr). This achieves the pre- determined value of Power Factor (PF).

OBJECTIVE To make power supply system for trains with betterment in scales of efficiency, cost, safety,weight,simplicity and reliability. Generally trains have rpm in normal speed. If we cover the axle by hollow cylinder with conductor slots and rotor mounted with permanentmagnets then this will make a alternator. A thin layer of insulation is provided to axle from rotor for high quality safety purpose. Holders confirm the connectivity of magnets and axle.

CONTINUED… Stator keeps interaction with magnetic field with the aid of hollow cylinder. The battery is connected to the alternator through rectifier-cum-regulated unit, which converts AC output of alternator into regulated DC and prevents the reverse flow of current from the battery to the alternator during periods of non-generation. The design with regulator cum rectifier has magnetic amplifier type control on field excitation.

CONTINUED… Subject to the condition that total current of alternator is less than rated current output the regulator shall regulate the output voltage of the alternator so as to maintain a pre-set voltage subject to the tolerance at the rectifier terminals under the following conditions: a) At all speeds from 800 RPM to maximum speed. b) At all loads ranging from 10A to the rated output of alternator [2].

CONTINUED… The regulator produces same output when input voltage is below 130 V.At very slow speed and at the time of breaking the output of rectifier cum regulator will be less than 30 V. This deenergises to relay, used between regulator and main battery as a switch and now the output of rectifier is feed to secondary battery charger. Although nominal condition for voltage in ac coaches is 110 Volt but rating is of 130 Volt.

RESULT The output voltage of power supply system is 130 V and almost 195 Amperes of current with 7 parallel rectifier cum regulator units, in normal conditions. Theoretically we will get 203 A but due to lose the current is same as above. The use of relay mechanism makes this system smarter.

ABOUT LHB COACHES The Linke Holfmann Busch (LHB) coaches are the passenger compartments of Indian Railways that have been developed by Linke-Hofmann-Busch of Germany (taken over by Alstom in 1998) and produced by Rail Coach Factory in Kapurthala, India. They are used since 2000 on the Indian Broad Gauge (1676 mm) network of Indian railways. Initially, 24 air conditioned coaches were imported from Germany that would be used for the Shatabdi Expresses, after which the Rail Coach Factory started manufacturing after technology tranfer.

CONTINUED… The coaches are designed for an operating speed up to 160 km/h and could go up to 200 km/h.[6] However, they have been tested up to 180 kmph. Their length of 23.54m and a width of 3.24m means a higher passenger capacity, compared to conventional rakes. These coaches are made of stainless steel and the interiors are made of aluminium which make them lighter as compared to conventional brakes.

CONTINUED… During , RCF produced 458 LHB coaches and 300 coaches during and has planned to produce 693 coaches during the fiscal. Presently LHB coaches are seen only in premium air-conditioned services such as Rajdhani, Shatabdi and Duronto trains owing to high cost of manufacture. However, Indian Railways have decided to replace the conventional ICF-made coaches with the LHB coaches in all the trains by the end of RCF, Kapurthala had started the production.

CONCLUSION Hence we will be able to not only reduce mechanical complexities but also cost and weight of power supply system will be also drastically drop. With all this trains can come with super efficiency power supply system.

CONTINUED… The air conditioning system of the LHB coaches is of higher capacity compared to the older rakes and is controlled by a microprocessor which is said to give passengers better comfort than the older coaches during summer and winter season. The noise level of these coaches is less as each coach can produce maximum noise level of 60 decibels while conventional coaches can produce 100 decibels.

CONTINUED The greatest advantage of LHB coaches is that the sound level of these coaches is hardly 60 decibels compared to about 100 decibels in conventional coaches. Less energy while creating heat and cool effect in these new coaches. LHB coaches are more comfortable due to its improved suspension system. The controlled discharge toilet system. These coaches have the capacity to accommodate about 72 passengers in each AC-3 coach as against 64 passengers in an AC- 3 conventional coach.

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