Solenoid Valves In Underslung AC Coaches

Recently there was a minor fire case in power car in N.Rly:-

shown above is the overheated solenoid valve coil.

Shown above are the heated up wirings in the vicinity of that solenoid.

Solenoid valve is an electromechanical device which is used to pass/block flow of oil/refrigerant in AC plants of underslung coaches. The coil of solenoid valve can be opearted at 110V Dc or 110 V AC or 230 V AC.
Solenoid in Power Car
Underslung AC power car has only one AC plant comprising one compressor, one condensor and two evaporators( one each for guard and power car staff). Each evaporator are fitted with one solenoid valve.Function of solenoid valve is to bypass refigerant from evaporator so that only non-cooled air is blown in. Location of this solenoid is at chest height in guard compartment.

coil 44 and 44a ( in right most line) is the solenoid in above drawing.

the blue device shown above is the 230V ac solenod coil, plunger of which is showm in the picture below:-


Solenoid in Coaches
Coaches have two AC plants ( one compressor , one condensor and one evaporator in each). Each of the compressor have one solenoid as shown in the bottom left corner in the picture below:-

Its function is to allow passage of oil in through the red pipelines so that compressor's duty can be halved ( allowing refigerant in only 2 out of 4 cylinders) in order to avoid inrush during starting.
Location of this vlave is under the coach body on each side.


this valve can be made off from inside the coach by the switch called "capacity control" as shown above.

During the course of time these solenoids have been bypassed electrically and mechanically from the coaches.