WELDING OF TRANSFORMER

The over hauling of welding plant transformer is also done her. It is a 440/80 Volt transformer. It has a junction circuit breaker. It has three controllers: one for on/off function, one for slow working and one for fast working.

ELECTRONIC BLAST:

The electronic blast is used in tube lights for its proper working. The electronic blast consists of following parts of specified ratings:

Name of Equipment	Remark	Ratings
Choke	1	11W, 110V   18W, 110V   20W, 110V
Electrolytic Condenser	5	10 µFarad, 450V   11 µFarad, 60V   100 µFarad, 50V   10 µFarad, 50V
Capacitor	5	0.22 µFarad, 400V
Resistor	10	2.2Ω, ¼ W   47Ω, ¼ W   470, ¼ W
Biasing Coil	1	_________________________
Transistor	1	1 MJE,1300S, NPN,   100N, 1NPN
HRC	3	6565
Diode	4	IN4007
Diode	4	IN4148
Resistance	2	16kΩ

PRE COOLING TRANSFORMER:

         

The pre cooling transformer is used in AC coaches. When the train stops at any station for more than 10 mins and is loaded with passengers, then the pre cooling transformer is attached to the main supply of the coach. This is done to maintain the comfort temperature of the coach because the batteries are not designed to bear so much load for such a long time. The pre cooling transformer is a 200 Amp, 440/220volts transformer. A rectifier is attached to this transformer which changes AC to DC. The 3-Ω supply is given to HRC fuse. ML4 contactor is connected to these fuses. The rating of this contactor is 70Amp, 415Volts. The supply is given to the rotary switch which is a 4 pole, 4 way, 63 Amp switch. The primary coil of transformer consists of two type of winding – fine and coarse.