Sunday, May 17, 2020

TOKENLESS BLOCK INSTRUMENT (HANDLE TYPE) FOR SINGLE LINE - PART 3

Operation or Testing Procedure for TLBI

1. Normal Condition


- Handle in Line Close position
- SM key, SH key, S1, S2 are in Normal position.
- TOL, TRI indication - Normal
- Needle indicator - zero position
- All relay except 1R and 1TPR are in drop condition.

This condition is indicated by Signal  Normal indication LED ON


2. When A train is Leaving Station A to Station B

 1)PB1 pressed for Audio Call Signal

At Station A
SM key- On
- PB1 - Pressed
- A DC(-ve) flow to stn B to pick up BLR at Stn B.
- At Stn A, Y Relay picks up, X Replay picks up .
- The DC Line supply B30 flows through circuits to Stn B  to Pick up BLR with returning path to Stn A to N30.

At Station B

- BLR picks up , with BLR picking up the bell rings even if the SM key is in OFF/ON.
- At Stn B , upon received of a CALL ATTENTION SIGNAL, SM key is turned ON.
- PB1 is pressed to issue an answering call to stn A.


 2)Transmission of TCF CODE & Other Station Handle Go to N to R.

- At Station A, 
- PB1 an PB2 button Pressed together.
- PBPR  Relay - Picks up
- X, Y Relay - Picks up
- With PBPR picks up, Line current Flow through terminal (25, 26) to Stn B to picks up NR relay with returning path to Stn A.
- With NR picks up a bell rings at Stn B.
- BLR doesn't picks up as current flow in opposite direction.

- As PBPR picks up at Stn A, A Voltage applied to FM Transmitter , As RB(1 & 2) are shorted for Normal R handle position making Coupler Pin 5 & 6 of Tx shorted, it generates a modulated signal F1(85 Hz) as per its internal circuitry and flows to stn B to terminal (34,24) and (37, 27) via VF transformer. 

- On receipt of the modulated signal at Stn B, Handle turned to Y position to feed DC voltage to receiver , thus giving Receiver output to pick up CR1 Relay 

With CR1 & NR picking up at Stn B, LOCK MAGNET COIL is energized ,thus LOCK magnet is released enabling the Handle to rotate from N to R(TCF).

When BLOCK HANDLE is being turned from N to R
  - RB(33,34) is open at Y position 
  - And a Resistance R5(470 ohms ) is added in the circuit resulting a reduction in the line current.
  - This causes the Galvonometer to show flick making it possible to know at Stn A that Block 
    Handle has been turned to R at Stn B.
  - Then PB1 and PB2 at Stn A may be released causing CR1 to drop at Stn B.


 3)Transmission of TGT CODE & Other Station Handle Go to N to L.


At Stn B,

- Galvo is at Zero position
- PB1 and PB2 pressed together to send signal code to stn A.
- X and Y Relays and PBPR relays picks up at Stn B
- NR picks up at Stn A.

As PBPR picks up at Stn B, A Voltage applied to FM Transmitter ,As BLOCK HANDLE is already in R- Position, RB(1 & 2) are shorted making Coupler Pin 5 & 7 of Tx shorted, it generates a modulated signal F2(65 Hz) and flows to Stn A to terminal (34,24) and (37, 27) via VF transformer. 

- On receipt of the modulated signal at Stn A at Pin 1 through terminal 34 and Pin 2 through terminal 37, Handle turned to X position to feed DC voltage to receiver (Pin 3) , thus giving Receiver output to pick up CR2 Relay 

- When CR2 picks up, TRSR picks up.

- As TRSR picks up, LOCK MAGNET COIL get voltages and BLOCK HANDLE turned to X' position from X position allowing TRSR relay to stick through its own contact .

- With TRSR and CR2 picking up handle can be turned to L (TGT) position.

- Confirming for Galvanometer flick at Stn B.

- PB1 and PB2 may be released from Stn A.











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Location: Dhanbad, Jharkhand, India

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