Battery and Battery charging circuit
Battery Battery - It is a device which converts chemical energy into electrical energy. It is a combination of two or more cells.
Primary Cell – It can not be recharged.
Secondary Cell – It can be recharged.
Charging – During this process electrical energy is converted into chemical energy.
1. Lead Acid Battery
2. Nickel Cadmium Battery
1. Lead Acid Battery: In Diesel loco 8 Lead acid batteries are provided, each battery contains 4 cells of 2 volt and each battery voltage is 8 volts. All the 8 batteries are connected in series therefore total battery voltage is 64 volts. In 14 series loco battery No.1, 2, 3 are located at the left side and 4, 5, 6 batteries are located at right side of loco near alternator room and battery No.7, 8 are fitted in loco left side near nose compartment. In 13 series loco battery No.1, 2, 3,4 are located at the right side near alternator room and 5, 6,7, 8 batteries are located at left side of loco near nose room. The positive terminal of battery No. 1 and negative terminal of battery No. 8 is connected to battery knife switch. The capacity of battery is 450 ampere hour and its normal charging current rate is 10 - 20 amps approx. In each cell of the lead acid battery positive plate is made of lead oxide (PbO2) and negative plate is of lead (Pb).Both plates are separated by separator plate and immersed in electrolyte. The electrolyte level should be 1.25 inch above the separator plate. The vent plug is provided for each cell.
Use of battery before engine starting –
1. To crank the engine.
2. To charge the control circuit of Loco.
3. To start FPM and CCM.
4. To charge the lighting circuit of Loco.
Battery is charged by Auxiliary Generator after engine starting.
2. Nickel Cadmium Battery/ Alkaline Battery
As a modification 11 Nickel Cadmium batteries are fitted in some Loco. Out of 11 batteries, seven batteries are of 4 cells and remaining is of 5 cells. Each cell is of 1.2 Volt and total voltage of batteries is 58 volts.
The capacity of battery is 240 ampere hour and its normal charging current rate is 24 - 48 amps approx.
In each cell anode (+ve) is made of Nickel oxide and cathode (-ve) is made of cadmium. The both plates are immersed in electrolyte. Use of these batteries in the loco is same as lead acid batteries. It is charged by Auxiliary Generator after engine starting but its initial charging current is high which is become normal after some time. It is not necessary to check the electrolyte level in the battery.
Advantages of Nickel Cadmium battery –
1. Less time is required for charging.
2. Maintenance cost is less.
3. Long life.
4. No need to check electrolyte level.
Battery charging circuit
The batteries in Diesel loco are charged by the Auxiliary generator with constant voltage i.e. 72±1 volt. The Voltage Regulating Panel (VRP) controls output of auxiliary generator with the help of VRCLS, irrespective of engine speed. VRCLS is provided to limit the current; its setting is 160 Amp.
Description of circuit – At the time of Engine starting , when BS is ON battery supply goes to wire no. 49, AG armature, wire no. 44c,VRCLS, wire no. 44D,AGFL, wire no. 44F, BAS and wire no. 44k (battery negative) and circuit completed. After this AGFL will glow.
After engine starting AG starts to generate current initially on the principle of residual magnetism. This current goes to excite the field of AG through VRP when AGFB is put ‘ON’. As AG output more than battery voltage then the current starts flowing in wire no. 49. This current starts to charge battery via wire no. 49, BS (+ve), Battery, BS (-ve), wire no. 44k, BAS, wire no.44F , MB1,4 , RCD, 44D and VRCLS, wire no. 44C. As soon as battery starts charging, AGFL lamp will extinguish. AGFL lamp will glow when battery is discharging or AG is failed.
The battery ammeter is provided on front panel to show charging/ discharging of battery. It has marking of 0-200 Amp both side. Each mark is of 10 Amp. It shows charging current when needle is in the right side of zero and in the left side it shows discharging current.
Auxiliary generator is failed/ Battery is discharging -(In this condition Auxiliary generator failure lamp glows continuously and Battery ammeter shows discharging current.)
Battery over charging
If BA showing excessive charging current and smell of acid is coming, it indicates that battery is over charging. In this condition following items to be check –
1. If battery is over charging only on higher notches than the VRP is faulty. In this condition open the BS on higher notches and close it on lower notch / Idle.
2. Check the electrolyte level in battery if less, than inform to PCOR.
3. If any battery is faulty, try to isolate it.
Battery is not charging –
