TRAIN LIGHTNING SHOP

The shop deals with the periodical over haul of the fans, batteries and the rotary switches used in the train. The basic details of the equipments over hauled in this shop are as follows:

Fans:                 

The fans used in the train are mainly of two types:

1.                  DC fans

2.                  AC Fans

DC Fans:

This type of fan is mainly used in the general and sleeper compartments of the train. DC series motor is used in this type of fan. It works on 110 volts dc supply. The ratings of this type of fan are 110 volts 2 amp.

It has lap winding on the armature circuit at an angle of 90 degree. The stator consists of field coil and two poles. These poles are magnetic poles. It has two ball bearings one at the top and other at the bottom. It has two carbon brushes, carbon cap and carbon holder for ball bearing. The winding is made up of copper wire. The insulation between windings is done through glimmer paper of 5mm thickness.

AC Fans:

This type of fan is used in the AC compartments of the train. It is singles phase capacitor run type fan. The motor used in the fan is an induction motor. The ratings of this type of fan are as follows:

Voltage: 230 volts

Current: 0.5 amps

Speed: 350 rpm

The stator winding is divided in two parts; auxiliary winding and main winding. These windings are in parallel with each other. A capacitor is joined in series permanently with the auxiliary winding both in starting and running condition.

These fans are quiet, self starting, efficient, smaller and need less maintenance. These fans can be fixed on moving type. The moving type fan has a grumble ring on which the fan rotates.

Fan testing board:

The fans who are POH have been done are tested through fan testing board for proper working and efficiency. It has ammeter, voltmeter, and wattmeter. The voltage setting for dc fans is 110 volts and for ac fans is 230 volts. The load current should be in between 0.28-0.40 amp. The IR value (insulation Resistance) should be 20 Mega ohms minimum.

Batteries:

Batteries are one of the most important requirements of the train. When the train stops and the alternator stop working battery takes the full responsibility of train lightning. These cells are designed for rugged service. This shop deals with the periodical overhauling and maintenance of these batteries. New cells are initially charged and old cells are periodically overhauled in this shop.

Initial Charging:

The filling plugs are removed and the cells are filled with pure Sulphuric acid previously diluted to specified specific gravity to the maximum indicating mark.

Specific Gravity for filling in new cells	1.190
Specific Gravity of electrolyte at the end of charge	1.21. to 1.215
Maximum permissible temperature of electrolyte during charge	50 degree.

These batteries are allowed to stand for 12 hours. The electrolyte is stored to original level. The battery should be charged at first charge current of 3.5 amp per set for 80 hours. After 18 hours specific gravity and voltage of the cell should be measured. Specific gravity should be in between 1.210 to 1.220 and voltage should be in between 6.3 to 6.4 volts per mono block or per cell. These batteries are given rest for 12 hours.

These batteries are then discharge through discharge plant at rate of 12 amps per set. After discharge specific gravity should not be less than 1.110 and voltage should be 4.5 volts.

Normal Charging:

The normal charging is done at rate of 12 amps per set up to a min of 12 hours. The specific gravity should be in between 1.210 to 1.220. Specific gravity is rated so because the internal resistance of the electrolyte is min in between.

These cells are then given rest for 8 hours and then they are ready for use.

Trickle charging:

Trickle charging is also known as slow rate charging. If the cells are not used they are charged as slow rate i.e. 3.5 to 4.5 Amps per set.

Slow rate charging is also used as a treatment for POH. During this process the electrolyte is taken out and the cell is filled with distilled water. Then they are charged at rate of 3.5 amps per set for 80 hours. After 80 hours all cells are opened and distilled water is poured out. An electrolyte of specific gravity 1.250 is filled and cells are normally charged at rate of 12 amps per set for 12 hours. Then they are discharged at a rate of 12 amps per set. Then they are again charged at rate of 12 amps per set.

POH of old batteries:

Periodical overhauling of old batteries is done to check whether they are in condition for further use or not. In this process old cells are charged for 16 hours at rate of 12 amp per set. Then their specific gravity is and voltage is measured. If they are more than 80 % of the standard values, then they are discharged at rate of 1 amp per set for 8 hours. These batteries are then again charged for 8 hours at rate of 12 amps per set.

Rotary switch board:

Rotary switch board is also known as upper frame junction box. This junction box has two main junctions positive and negative. The positive and negative terminal from the upper frame terminal and the four positive and three negative distributions wires of SPM meet at this junction box. All positive terminals meet at the main positive and the negative terminals meet at man negative.

The main negative has a HRC fuse (High rupturing Capacity) in series of 32 amps. The main positive has 4 points. All 4 points have a HRC fuse of 16 amps each in series. Three rotary switches are connected in series with three of the points. The fourth point work as an emergency terminal. In case the light system of the coach fails it provides emergency light to the coach through EFT from other coaches.

Rotary switch 1 is for light 1 which provides 70% of the light in the coach. Rotary switch 2 is for light 2 which provides 30% of the light in the coach. It is responsible for the light in the galleries and the night light. Rotary switch 3 is for fans. In the entire junction is responsible for the lightning system in the coach.