Traction Rolling Stock - Indian Railways Institute of Electrical ...

These machines are capacitor start and run single phase induction motors and are
protected by individual fuses MCB on the live side of each machine. Also connected directly
across the 266V supply is a no-volt relay NVR. This is a d.c. relay fed by a bridge connected
rectifier, and is used to detect when the transformer is 'ive. On failure of line voltage, NVR drops
out and disconnects the traction circuit by means of its contacts NVR1 and NVR2 in the control
circuits. The NVR circuit is protected by a miniature circuit breaker.
The aux.2 winding is protected against a fault in the wiring of the 266V a.c. circuit by two
main fuses API and AF2,situtated within the transformer connection chamber.
10.5.2 141V a.c. circuit (Ref. fig. 10.5.2)
This circuit is fed from a second tertiary winding aux. 1 (141V ac) and is protected by
two fuses AF3 and AF4,located inside the transformer connection chamber.
A rectifier-fed relay LTR is provided to prove that fuses AF3 and AF4 are intact and that
the voltage of aux. 1 winding is applied to the auxiliary supply rectifier (ASR). The circuit of LTR is
protected by a miniature circuit breaker.
A surge suppression capacitor with a series resistor is provided across the input to ASR.
10.5.3 Main-compressor motor (Ref fig 10.5.2)
The main compressor motor is protected by fuse AF10 and a permanent series resistor,
and its contactor CC1 which is in turn controlled by a trip and set relay CR, through the
compressor governor.
Compressor synchronising is achieved through train line wire 13.
When the COMPRESSOR SET button in any driving cab is pressed, train line 12 is
energised, setting all the compressor relays in the train and the contact CR/1 completes the
respective compressor contactor coil (CCl) circuit. This closes the compressor contactor.
To switch off the compressor motors the COMPRESSOR TRIP button in the cab is
pressed this energises train line 42, tripping the compressor relays and the compressor
contactors.
A sealed switch GS3 is provided to short circuit the main-compressor governor if it sticks
in the open position. Two miniature circuit breakers protect the circuit in such a way that faults in
various parts of the circuit do not disable the train. The blocking rectifier between wire 1445 and
1446 is provided to prevent the batteries in two units operating in multiple from being connected in
parallel.
10.5.3 Smoothing reactor
This is provided to smoothen the ripple on the output of the auxiliary-supply rectifier.
This voltage is then fed to the fans.
10.5.4 Ventilating fans