43 Section D..General Auto Electrical Corporation 1. LED Based Signal unit GAEC manufacture LED based signaling system for use in electrified and non electrified sections of Indian railways. The exceptional reliability of Led provides lower maintenance cost and guarantees reduction of train delays as compared to the present conventional lamps. The LED signaling system comprises of LED signal unit, current regulator and health monitoring unit. The unit is retrofit able in existing colour light signal unit. LED units are available in Red, Amber, Green and white. LED units comprises of LEDs divided into multiple arrays to enhance redundancy. The LEDs are placed in an ABS enclosure and provided with UV stabilized polycarbonate lens. The signal unit is hermetically sealed. The current regulator ensures constant light intensity over a wide range of input voltage. It has a unique
44 feature of blanking and non blanking mode which facilitates to keep the LED signal aspect ON even if there are only few arrays glowing. The feature is most useful for automatic signaling having cascading circuit. Health monitoring unit (HMU) is provided at the relay room to monitor the current fed to the current regulator. Based on the current, various indications are displayed on HMU card and accordingly potential free contacts are switched to provide remote alarm. The system design enables the HMU to provide preventive maintenance indications when 15% to 20% of arrays are extinguished. GAEC also offer LED based auxiliary signals such as Calling on signal, signals for LC gates, route indicators and shunt signals. In this case, the LED signal and current regulator is enclosed in the common enclosure. 2. Features: Light emitting diode technology offers the ultimate in reliable resulting in lower operation/ maintenance cost. Constant intensity over a wide range of voltage Visibility over 600 meters. Compatible with SSI and relay based signaling system. Retrofit able system Viewing angle to meet signaling requirement Phantom free design Low power consumption
45 Long service life. Low whole life cost In case of failure of one LED variation in light output drops by les than 5% interchangeable current regulator Isolation with main line supply : 2KV. 3. Specifications 3.1 LED Signal unit (Main Aspect) Colour of the unit Red/Yellow/ Green Power supply Common regulator unit operated on 110 V AC Operating temperature -10 C to 60 C (RH up to 90%) Illumination >110 lux @ 1.5 in axial direction Colour co-ordinates Red/Green: Class C of BS 1376-1974 Yellow: Class B of BS 1376-1974 Overall size 180 mm Dia x 100 mm ± 2 mm Isolation 2kV AC (RMS) for 1 minute Insulation > 100 M ohms Dispersion < 8 deg Net weight 0.400 kg
46 3.2 Current Regulator Normal input Input variation ± 20% Input current 100V AC, single phase 50 Hz 124 ma ±5% (with 110V ±20% and -10 C to 60 C Load regulation ±2% (from 88 V to 132V) Noise immunity 60V AC (min) Operating temp. -10 C 60 C (RH 90%) Overall size 240x90x45mm (LxBxH) ±2mm Isolation 2kV AC (RMS) for 1 Insulation Net weight minute > 100 M ohms 1.500 kg.
47 3.3 Health Monitor cum alarm unit Main input 110Volts AC, single phase 50Hz Input variation ±15 % Aux input 24 V DC Input variation ±20% Operating temp. Features -10 C to 60 C (RH up to 90%) One set of potential free contracts for remote sensing. Aux supply ensure working of unit during power failures Modular construction for easy and fast erection, identification and maintenance replacement. Unless specified LED units shall be supplied to use with ECR for LED signals only.
48 3.4 Block Diagram of LED lighting unit Block Connection Diagram of the LED signal Lighting Unit 110 V AC, 1Ph, 50 Hz Signalling Relay Circuit ECR Fuse Potential free contacts for remote sense Health Monitoring Unit 100 V AC main supply 24 V DC Aux supply AC Current Regulator LED Signal