LED SIGNALS IN

INDIAN RAILWAYS

WHAT IS LED?

IT IS A DIODE WHICH EMITS LIGHT OF REQUIRE COLOUR WHEN FORWARD BIASED.

INTERNAL STRUCTURE OF LED

Colour Wavelength Voltage Semiconductor Material

RED 610 < λ < 760 1.63 < ΔV < 2.03Aluminium gallium arsenide (AlGaAs)Gallium arsenide phosphide (GaAsP)Aluminium gallium indium phosphate (AlGaInP)Gallium(III) phosphide (GaP)

Yellow 570 < λ < 590 2.10 < ΔV < 2.18Gallium arsenide phosphide (GaAsP)Aluminium gallium indium phosphide (AlGaInP)Gallium(III) phosphide (GaP)

Green 500 < λ < 570 1.9[< ΔV < 4.0

(AlGaP) Indium gallium nitride (InGaN) / Gallium(III) nitride (GaN)Gallium(III) phosphide (GaP)Aluminium gallium indium phosphide (AlGaInP)Aluminium gallium phosphide

DOPING MATERIAL, WAVELENGTH AND OPERATING VOLTAGE FOR COLOUR EMITTED BY LED

WHAT IS LED SIGNALS?

IT IS REPLACEMENT FOR FILAMENT LAMP WITH LOT OF ADVANTAGES OVER DRAWBACK OF FILAMENT LAMP

OTHER SELECTION

BX110 V AC

NX110 V AC

Fuse 0.63 Amp

LED SIGNAL UNIT

AC I/P

DC I/P

MOTHER BOARD & HMU CARD #

#

ECR

UNIVERSAL CURRENT REGULATOR

Aspect control circuit with LED signal arrangement

UNDER GROUND CABLE

CLS Unit Relay room

ECR

OTHER SELECTION

BX110 V AC

NX110 V AC

Fuse 0.63 /2 Amp

##

OTHER SELECTION

BX110 V AC

NX110 V AC

Fuse 0.63 Amp

LED SIGNAL UNIT

AC I/P

DC I/P

MOTHER BOARD & HMU CARD #

#

ECR

UNIVERSAL CURRENT REGULATOR

UNDER GROUND CABLE

RELAY ROOM CLS UNIT

Comparison between filament lamp & LED circuit

Aspect control circuit arrangement with filament lamp & LED signal

ADVANTAGES OF LED SIGNALS

• Long life 1,00,000 hours .• Pre-focused. • Better visibility .• Very good short view .• No focusing on curved track.• Same type of ECR for all aspect and signal.• No phantom effect .

DISADVANTAGES OF LED SIGNALS

• Colour of LED change according to temperature and supply voltage.

• Its intensity of light is high which affect the sight of the driver.

Signal with Filament lamp & door open

Signal with LED lamp & door open

NO PHANTOM EFFECT

WHETHER LED EMITS NOMINATED COLOUR ONLY?

A good quality LED emits nominated colour only.

There is very remote possibility that it may emits wrong colour if biased current changes.

COMPONENT OF LED SIGNAL

FUSE LAMP CHECKING RELAY (ECR) HEALTH MONITORING UNIT (HMU) UNIVERSAL CURRENT

REGULATOR LED SIGNAL UNIT

COMPONENT OF LED SIGNAL

Health monitoring unit

Lamp checking relay ECR Universal current regulator

LED signal lighting unit

Fuse

FUSE TO BE USED WITH LED SIGNALS

Fuse shall be 0.63 Amps capacity.Whether fuse of 0.63 capacity is available in ND type open fuse?

ND type open fuse G type closed fuse

HEALTH MONITORING UNIT

Front View

Rear View

RELAY COMPATIBLE WITH LED SIGNALS

Any type of relay recommended (metal to carbon/ metal to metal )by Railway board can be useThere is a recommended ECR for LED signal The selection of jumper on the UCR shall be as per ECR used.

Sr Nob

Type of ECR Make

Suitability with LED signal

P-up & DA current Relay ContactsMain

C-ON

Route

Shunt

ON-Metal to Metal M/s ABB YES YES - - 180&110 ma 3F/3B

OFF-Metal to Metal M/s Siemens YES YES

- - 145&62ma 3F/3B front 2,12,13

& back 3,4 ,14

ON-Metal to Carbon

M/s CGL

Company code

YES YES YES YES

180&110 ma4F/B, front A1/A2 to

D1/D2Back A3/A4 toD3/D4QECX51

M/s Hytronic

s

HRC-1 180&110 ma

4F/B ,front A1/A2 to D1/D2

Back A3/A4 toD3/D4HMCR-1

108/110ma

3F/3B ,Front A1/A2,D1/D2 &

D3/D4Back A3/A4, A5/A6

&D5/D6LED AC

ECR-Metal to carbon

-QECX61

YES YES YES YES 108 & 72 ma4F/B , front A1/A2 to

D1/D2Back A3/A4 toD3/D4

LED DC ECR-Metal to

carbon-

QECR2 YES YES YES YES 80 &55ma

4F/B , front A1/A2 to D1/D2

Back A3/A4 toD3/D4Conventional

ECR Rest conventional ECR are not suitable for LED signal

Reference RDSO Latter Nob .STS/E EL-LED Dated 02.06.2006

RELAYS TO USED WITH LED SIGNALS

COMPONENT OF LED SIGNAL LIGHTING UNIT

Quality LEDs Sensors Poly-carbonet Dom

Power supply socket

Feed back socket

INPUT POWER SUPPLY, OUT PUT & FUNCTIONS

• Input to all type of LED signal unit is ±25% of 110 volts DC and AC.

• Input to LED signal unit for main aspect is taken from O/P of current regulator.

• O/P is beam nominated colour (110 Lux for OFF aspect & 120 Lux for ON aspect).

• Also gives feed back about light O/P to current regulator if sensors are provided.

INPUT POWER SUPPLY, OUT PUT & FUNCTIONS

Sr No LED signal unit FunctionIn put & connectio

nOut put

Minimum

Visibility

AC Immunity

AC I/P DC I/P

1

Main running signal

RED gives out red light beam

Optical output

Feedback to current regulator ( if sensors

are provided

DC & appro. 125% of Input of current regulator & current regulation ±2% & Direct

120 lux -

15% +25% 600Mts

AC noise immunity 60 Volts

300 volts AC

YELLOW gives out yellow light beam

GREENgives out

green light beam

110 lux -

15% +25%

2 Directional route indicator

gives out lunar white light beam

50 lux -15% +25% 400Mts

3 Calling ON signal gives out yellow light beam

50 lux -15% +25%

200Mts4 Shunt signal gives out lunar white

light beam 30 lux -15%

+25%

FRONT VIEW ON ASPECT RED OFF ASPECT YELLOW OFF ASPECT GREEN

REAR VIEW

LED SIGNAL UNIT FOR MAIN SIGNALS

WHETHER LED SIGNALS ARE AVAILABLE FOR MAIN SIGNAL ONLY ?

LED SIGNAL UNIT FOR ROUTE INDICATOR

LED SIGNAL UNIT FOR SHUNT SIGNAL

LED SIGNAL UNIT FOR CALLING ON SIGNAL

FRONT VIEW CALLING ON SIGNAL ROUTE INDICATOR SHUNT SIGNAL

REAR VIEW

LED SIGNAL UNIT FOR SUBSIDIARY SIGNALS

WHETHER LED LIGHTING UNIT IS FOR MAIN SIGNAL ONLY?

I/P POWER SUPPLY, O/P OF CURRENT UNIVERSAL REGULATOR

• Placed inside CLS unit.• I/P 110 ±20 volts AC/DC.• O/P 125% of I/P & always DC.• O/P Current regulation 2 %.

Sr No

Universal current regulator for

In put per unit Out put Function

current volts

1 Main running signal

Separate fixed in

CLS unit

AC 125 ma ± 5%

DC 105 ma ± 5%

AC/DC 110

VOLTS ± 20%

DC approxim

ate 125% of

I/P & current

regulation margin

2%

Supply constant regulate current to LED SIGNAL UNIT

Scope for adjustment of circuit current to suite pick up current of ECR

Scope for adjustment to suite cascaded and non-cascaded aspect control circuit.

Regulates current as per feedback from LED signal unit

2 Directional route indicator

Inbuilt

AC 25 ma ± 5%

DC 23 ma ± 5%

3 Calling ON signal

AC 125 ma ± 5%

DC 105 ma ± 5%

4 Shunt signal

AC 125 ma ± 5%

DC 105 ma ± 5%

I/P POWER SUPPLY, O/P & FUNCTIONS OF CURRENT UNIVERSAL REGULATOR

Note – parameter as per specification RDSO/SPN/153/2002

Sr No

Universal current regulator for

In put per unit Out put Function

current volts

1Main

running signal

Separate fixed in CLS

unit

AC 140 ma +10,-20 (rms)DC 125 ma

+10,-20 (rms)

AC/DC 110

VOLTS ± 25% DC

approximate

125% of I/P &

current regulation

margin 2%

Supply constant regulate current to LED SIGNAL UNIT

Scope for adjustment of circuit current to suite pick up current of ECR

Scope for adjustment to suite cascaded and non-cascaded aspect control circuit.

Regulates current as per feedback from LED signal unit

2 Directional

route indicator

Inbuilt

AC 25 ma ± 5%DC 23 ma ± 5%

AC/DC 110

VOLTS ± 20%

3 Calling ON signal

AC 150 ma +10,-20 (rmsAC 125 ma

+10,-20 (rms

4 Shunt signal

AC 55 ma ± 5%DC 50ma ± 5%

I/P POWER SUPPLY, O/P & FUNCTIONS OF CURRENT UNIVERSAL REGULATOR

Note – parameter as per specification RDSO/SPN/153/2004 effective from 1.1.2007

PARTS TO BE REMOVED IN SIDE THE CLS LIGHTING UNIT

Transformer 110/12 Volts 40 VAMECR (If provided )Signal lighting unit Inner colour lens

Outer Clear lensLamp holderLampClamp

PROVISION OF LED SIGNAL IN EXISTING FILAMENT LAMP CLS

• OUTDOOR ARRANGEMENT• Items to be removed from CLS unit:

– CLS Transformer & Lamp – MECR (if provided)– Lamp holder & clamp assembly – inner & Outer lens

• Items to be fitted:– Current Regulator – LED light unit

• INDOOR ARRANGEMENT• Items to be removed/add from Relay room:• Check 110 AC fuse, shall be 0.6 Amps • ECR, if it is not as per RB guide lines• If required Aspect monitoring card per Aspect of

HMU

PROVISION OF LED SIGNAL IN EXISTING FILAMENT LAMP CLS

PARTS TO BE REMOVED IN SIDE THE CLS LIGHTING UNIT

Signal lighting unit

PARTS TO BE REMOVED IN SIDE THE CLS LIGHTING UNIT

Inner colour & outer clear lens

Lamp, holder & clamp

Signal transformer

MECR

FIXING OF LED SIGNAL UNIT & UNIVERSAL CURRENT REGULATOR

• Fuse of Aspect control circuit shall be 0.63 amps.• Existing ECR & shall be as RB guidelines.• Make the jumper settings on UCR & HMU to suite ECR.• The availability/non-availability of cascading in Aspect

control ckt.• Make the jumper setting (blanking/non-blanking) on UCR

accordingly.• Check whether HMU is in circuit OR bypass mode.

CHECKS- DURING REPLACEMENT LED SIGNAL IN EXISTING FILAMENT LAMP CLS