Functions of Relays

FUNCTION OF RELAYSFUNCTION OF RELAYSFUNCTION OF RELAYSFUNCTION OF RELAYS

S & T PROJECTS WINGS & T PROJECTS WINGS & T PROJECTS WINGS & T PROJECTS WING

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DESCRIPTION AND FUNCTION OF RELAYS (PTJ TYPE PANEL)

1. SMR (Station Master’s Lock Relay)

a) Normally de-energised relay.

b) When the SM’s key is ‘IN’ SM’s knob is turned to normal it picks up.

c) When the SM’s key knob is reversed it drops.

d) It’s purpose is to prevent unauthorized operation of the control panel.

It’s contacts are used in LR/UCR,WLR & Button relay circuits in such a

manner that no operation is possible when this relay is dropped.

2. LR (Route initiating Relay)


b) It picks up through the knob reverse contact with exit button pressed &

with SMR picked up contact and sticks up until SM operates the knob to

normal position.

c) It drops when the knob is normalized as long as SMR is in picked up

condition. When SMR is in dropped condition, the operation of knob to

reverse does not pickup LR or once it picked up, it does not drop.

d) Its purpose is to initiate the route setting intended by the operator.

3. WNR (POINT NORMAL CONTROLLING RELAY)

a) Normally de-energized relay.

b) It picks ups through the WLR and Normal contact of the point knob or

LR.

c) Its purpose is to initiate point operations from Reverse to Normal.

4. WRR (POINT REVERSE CONTROLLING RELAY)


b) It picks up through the WLR and reverse contact of the point knob or

LR/RR.

c) Its purpose is to initiate point operation from Normal to Reverse.

5. UCR (ROUTE CHECKING RELAY)


b) It picks up when route is set correctly, conflicting signal ASR in picked up

condition, KPR (Key Locked Points) in picked up condition and signal

knob is reversed.

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c) When the signal knob is normalized it drops.

d) The purpose of this relay is to check the correct setting of route and

conflicting signals are not taken off i.e. interlocking between conflicting

signals is achieved at this stage. The picking up of this relay causes ASR

to drop and locks the route.

6. WLR (POINT LOCKING RELAY)


b) It picks up when LR picks up (when point is operated by route setting )

(OR) when the point knob is operated from Normal to Reverse or

Reverse to Normal when point is free to be operated i.e., not locked by

any movement of train (ASR picked up) and point track circuit is in

picked up condition.

c) It drops as soon as Route is locked.

d) Its purpose is to lock the point as soon as the point is included in a

signaled move or when the point track fails.

7. NWKR (NORMAL POINT DETECTION RELAY)

a) Energised when point is normal & normal detection contacts made.

b) It picks up through the Normal detection contact of the point machine.

c) It drops when the point is initiated to Reverse.

d) Its purpose is to prove the normal setting of the point. It lits point

indication near the point knob and also picks up NWKSR.

8. RWKR (REVERSE POINT DETECTOR RELAY)

a) Energised when point is reverse & reverse detection contacts made.

b) It picks up through the Reverse detection contact of the point machine.

c) It drops when the point is initiated to Normal.

d) Its purpose is to prove the reverse setting of the point. It lits point

indication near the point knob and also picks up RWKPR and RWKSR.

9. NWKSR (NORMAL POINT STICK RELAY)

a) Energised when NWKR is energised.

b) It picks up through NWKR and sticks through CHR pick up contact WLR

back contact and its own front contact bypassing the NWKR.

c) It drops when WLR relay picks up for the operation of the point or CHR

and NWKR drops.

d) Its purpose is to avoid the route release failure in case of point detection

bobbing under the train movement.

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e) To achieve parallel movements NWKSR contacts are used instead of

NWKR to avoid signal bobbing.

10. RWKSR (REVERSE POINT STICK RELAY)

a) Energised when RWKR is energized

b) It picks up through RWKR and sticks through CHR pick up contact WLR

back contact and its own front contact bypassing the RWKR.

c) It drops when WLR relay picks up for the operation of the point or CHR

and RWKR drops.

d) Its purpose is to avoid the route release failure in case of point detection

bobbing under the train movement.

e) To achieve parallel movements RWKSR contacts are used instead of

RWKR to avoid Signal bobbing.

11. NWKPR (NORMAL POINT DETECTION REPEATING RELAY)

a) Repeater of NWKR.

b) It picks up through NWKR front contacts.

c) It drops when NWKR drops.

d) It proves the point detection (through NWKR front contact). Its contacts

are used for point proving in the interlocking. Point set indication on the

panel is given through NWKPR front contact.

12. RWKPR (REVERSE POINT DETECTION REPEATING RELAY).

a) Repeater of RWKR .

b) It picks up through RWKR front contacts.

c) It drops when RWKR drops.

d) It proves the point detection (through RWKR front contact). Its contacts

are used for point proving in the interlocking. Point set indication on the

panel is given through RWKPR front contact.

13. WNPR: (Point Normal Controlling Relay)

a) Normally de-energized Relay.

b) It picks up in Point Location when point operation is initiated to Normal.

c) It drops when Point is set to Normal and NWKR picks up in relay room.

d) The purpose of this relay is to initiate point operation to Normal.

14. WRPR : (Point Reverse Controlling Relay)


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b) It picks up in Point Location when Point operation is initiated to Reverse.

c) It drops when point is set to Reverse and RWKR picks up.

d) The purpose of the Relay is to initiate Point operation to Reverse.

15. NWR : Normal Point Operating Relay.


b) It picks up in Point location whenever Point is initiated to operate to Normal.

c) It drops when point is set to Normal, NWKR picks up in relay room and

WNPR drops in Point Location.

d) The purpose of this relay is to operate the point to normal.

16. RWR: Reverse Point Operating Relay.


b) It picks up in Point Location whenever Point is initiated to operate to

Reverse.

c) It drops when point is set to Reverse, RWKR picks up in relay room and

WRPR drops in Point Location.

d) Its purpose is to operate the Point to Reverse.

17. N/R Relay (Normal /Reverse Relay)


b) It picks in Point Location whenever Point is operated from Normal to

Reverse or vice versa.

c) It drops after a time gap (7-10 Sec) of XR relay picking up.

d) Its purpose is to keep WCR is picked up condition for a desired limited

time.

18. XR


b) It picks up after N/R picking up in Point Location.

c) It drops as soon as the Point is set to the required Position, concerned

NWKR or RWKR has picked up in relay room and Point controlling relays WNPR or WRPR drops in point location.

d) It prevents hunting operation of Point controlling circuits in Location in

case of obstruction in the point. Also the timing of (7-10Sec.) Point feed

is controlled by this relay.

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19. WCR (Point Operation Controlling Relay)

a) It is normally de-energized relay.

b) It picks up through N/R, XR and Point machine NC/RC contact.

c) It drops when N/R relay drops (after 7-10 Sec. of point Operation).

d) Its purpose is to carry high point motor current during Point operation.

20. UGR/HR (ROUTE INDICATION/SIGNALS CONTROLLING RELAY)

a) Normally de-energised.

b) It picks up when UCR picks up and all required track circuits in the route

& overlap are in picked up conditions, and level crossings in the route are

closed and locked against road traffic.

c) It drops when the train occupies first track circuit in advance of signal.

d) The purpose of UGR relay is to light the route lamps for loop line

reception. First UGR picks up and lights the route lamp then only HR

picks up.

e) The purpose of HR relay is to control the signal caution aspect.

21. ASR – (APPROACH STICK RELAY)

a) Normally energized Relay.

b) It picks up on arrival of train by occupation and clearance of track

circuits sequentially or by cancellation process. Then it sticks through its

own pick up contact.

c) It drops when UCR picks up.

d) Its purpose is to lock and hold the route i.e. LOCKS the points in the

route when the signal is taken off.

e) ASR picking up indicates that the connected route is free and points in

the route can be operated.

22. TPZR, TPZR2, TSSLR RELAYS.

a) Normally de-energised Relays.

b) They pick up when the train occupies and clears track circuits

sequentially.

c) They drop when ASPR picks up.

d) Their purpose is to pick up ASR (to release the route) during normal

movement of train on signals.

23. JSLR


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b) It picks up through the back contact of ASPR and signal knob Normal,

back lock track circuits unoccupied condition.

c) Drops when ASPR picks up.

d) Its purpose is to initiate time delay cancellation relay circuit.

24. TSR : (TRACK STICK RELAY)


b) It picks up through the first TPR pick up contact (in advance of a signal)

and ASR pick up contact. It sticks through its own pick up contact

bypassing ASR.

c) It drops when the train occupies first track circuit in advance of a signal.

d) Its purpose is to achieve one signal, one movement principle.

25. CHR : (CRANK HANDLE CHECKING RELAY)


b) It picks up through the key ‘IN’ contact of crank handle RKT.

c) It drops when the crank handle is removed from the RKT.

d) Its purpose is to ensure crank handle interlocking with signals.

26. ECRS (LAMP PROVING RELAYS)

A) RECR: (Red lamp checking relay)

a) Energises when RED aspect is lit correctly.

b) It drops when main filament of red aspect is fused.

c) Its purpose is to achieve indication locking and to give panel

indication.

B) HECR/DECR (OFF ASPECT CHECKING RELAY)

a) Energises when yellow/green aspect is lit correctly.

b) Drops when both main and auxiliary filament have fused.

c) Its main purpose is to control the aspects of rear signals and also to

give panel indication and its back contacts are used for cutting in

arrangement of signal aspects.

C) UECR (ROUTE ASPECT CHECKING RELAY)

a) Normally de-energised Relay.

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b) It picks up when route lamps are correctly lit (at least 3 bulbs of

110V 25W).

c) It drops when more than two route lamps are fused.

d) Its main purpose is to pick up HR during reception on loop line and

also to give panel indication.

D) CHR-CR (CRANK HANDLE LOCK RELAY)


b) It picks up through de-energized contacts of UCR and HR of

concerned signals.

c) It drops when the concerned signal is taken ‘OFF”.

d) Its purpose is to ensure that the concerned signals are not taken

‘OFF while extracting the crank handle.

27. NJPR (NORMAL TIME LAG PROVING RELAY)


b) It picks up after a prescribed time (120 or 60 Sec.) through JSLR front

contact and JSR front contact and cold contact of the timer in case of

thermal time element relay.

OR

It picks up after a prescribed time (120 or 60 Sec.) through JSLR front

contact and electronic time element relay output supply.

c) It drops when JSLR drops.

d) Its purpose is to achieve time delay and cancel the route by picking up

the concerned ASR.

28. RJPR


b) It picks up through respective JSLRs de-energized contacts.

c) It drops when the route cancellation is initiated i.e. JSLR picked up.

d) Its purpose is to permit one route cancellation at a time.

29. ‘R’ Relay


b) It will be in the picked up condition as long as power supply to PI/RRI is

available and slow to pick up feature is available.

c) It drops when power supply fails.

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d) It prevents inadvertent releasing of route during power flickering without

actual trains occupying and clearing the track circuit in signaling system

when battery back up is not provided for TPRs.

30. CO-ERR (Calling on Signal Emergency Route Release Relay).


b) It picks up whenever emergency calling on route cancellation has to be

done during the failure of back lock track circuit.

c) It drops as soon as calling on route cancellation is completed.

d) Its purpose is to initiate calling on emergency route cancellation process

during failure of calling on signal back lock track circuit failure.

31. LCXR, LCAR, LCPR (Level Crossing Gate Controlling Relays).

i) LCXR/LCAR : LC gate controlling relays – proves that the routes of

signal controlling the LC gates are not locked while

opening the gate for Road traffic.

ii) LCR/LCPR : Proves that the gate is closed & locked for Road traffic and

concerned signals interlocked with LC gate can be taken

‘OFF’.

32. LR, KPR (Siding Point Controlling Relays)

i) LR : Siding point controlling knob proving relay. It picks up when

siding control is released from the Panel proving that the

concerned signal routes are free.

ii) KPR : Siding point checking relay. It proves that the siding point is set in favourable position before the concerned signal is taken

‘OFF’.

33. LOHR/ROHR (Overlap holding Relays)

1. Normally in energized condition.

2. Drops as soon as the Home signal route is set & locked.

3. It picks up after a time delay of 120 Sec. of clearing the last back lock

track circuit by the trains.

4. Its purpose is to hold the points/LC in the overlap.

34. LOVJSLR/ROV JSLR, LOVNJPR/ROVRJPR (O/L Time delay relays)

1. Normally in de-energised condition.

2. Its purpose is to initiate time delay for releasing the overlap portion,

when the starter is not taken off.

35. GFXR (Signal blank indicating relay.


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2. The purpose is to give warning when any of the signal is blank including

failure of route indicator lamps.

36. GXR/MECR (Main Filament fused indicating relays).


2. Its purpose is to give warning when any of the main filament of a signal

lamp is fused.

37. TPR : (Track Circuit Repeater Relay):


2. Picks up through the track circuit relay (TR) pick up contact.

3. Its purpose is to prove that a particular track section is free of trains

before clearing a signal.

38. RECPR/HECPR/DECPR/UECPR:

1. Energises when RECR/HECR/DECR/UECR respectively in picked up

condition.

2. Works as a repeater of RECR/HECR/DECR/UECR respectively.

3. Used when the contacts of RECR/HECR/DECR/UECR respectively are

inadequate.

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Functions of Relays