Signotron has research and development experience of more than 35 years in the field of Power Electronics , Embedded Electronics and control for rolling stock and Industrial application.In this journey , Signotron developed expertise in many domains in Electronics and Electrical Engineering fields. For SMPS and Battery charger applications Buck , Boost , Buck Boost , Flyback , Pushpull , Forward , Bridge , dual active bridge topologies are used in hard switching and soft switching mode as per requirement . For Inverters and VVVF AC Motor drives Flyback , Half Bridge and single phase , three Phase Bridge topologies are used . . .

Technology Innovations Through The Years (1985 - Present)


Public Address and Passenger Information System (PAPIS) and End of Train Telemetry System (EOTT)


Underslung Regulated Battery Charger cum Emergency Battery chargers for all types of LHB coaches

SMPS based power supply panel for S & T

12 kW Battery charger for Electric Loco with IGBT based front end


Underslung regulated battery chargers for all types of LHB coaches

Compact Emergency Inverter for HVAC systems for Metro Railways


Active Harmonic filters in industries for improving power factor to near unity and reduction of current harmonics


SignoFlex EV20 SMPS for E rickshaw Battery charging

180 KVA Auxiliary Converter for electric locos


SignoFlex (HFC 6-3) Battery Charger

Turnkey solution for DC systems in power utility


Solar Power Plant designing & installation


Emergency Inverter for HVAC systems for Metro Railways


25 KVA Inverter for SGAC coaches of Indian Railways

Output paralleling of grid-interactive 3 phase solar inverters


Web-based remote monitoring and control (SCADA) for solar inverters


Grid-tied Solar Inverter up to 100 KW rating introduced

Static VAR compensator for Power Factor improvement, introduced

IGBT based Battery Charge / Discharge panel with active PFC up to 70 KW


28 KW naturally-cooled Battery Charger with active P.F.C. for SGAC coaches of Indian Railways

Supplied more than 1000 units to Indian Railways to date


Thyristor based Battery Charger with regenerative Discharging for VRLA batteries up to 70 KW


Commencement of Bulk Production of 3 phase Compact drives. Now full diesel fleet of Indian Railways has been installed with such compact drives. Total field population around 14000 as of date


Field trials of small AC Motors with Built-in Inverters by Indian Railways for 100% replacement of existing small DC Motors


Prototype unit for 3 phase Compact drive for Pump and Blower Motors for Diesel Locomotives in place of DC Motors


Inverters 0.5 KVA to 5 KVA for Pantry Car applications

5 KW DC-DC Converters for Hotel load applications of Diesel Locomotives for Sri Lanka Railways


Diversified our scope to Power Electronics products in Indian Railways' Rolling Stock.

MOSFET based Voltage Regulators for Motor Generator Sets of DC EMUs, in Indian Railways

Developed energy-efficient electronic lamp ballast for Railway Coaches

DC-DC Converter for Head Light Application in Indian Railways in place of Rheostat controlled headlights


The company's major thrust had been in manufacturing specialized Industrial Control products for Burner and Pollution Control- UV Flame Detector and Amplifier and a Microprocessor-based Back Feed Sequence Controller. Having more than 10000 installations in India and abroad, the above products were supplied in Steel and Cement Plants, Oil refineries and Chemical Industries


At Signotron, we endeavour to constantly upgrade to achieve future growth and maintain the highest quality of our products and services, and we do so.

We aim at the #1 position in the industrial and power electronics field in India. Our foremost priority is to comply with all statutory and regulatory requirements of our valued customers and continually improve the effectiveness of our quality management system as per the international standard ISO 9001: 2015.

We have established and regularly review our Quality Objectives based on this Quality Policy, ensuring that this policy is communicated to and understood by all within the organisation and relevant interested parties.


  • On-time delivery of defect-free products
  • 360-degree product life-cycle support
  • Continuous up-gradation and optimal utilization of infrastructure and human resources
  • Mutually beneficial alliances with suppliers and vendors
  • Continuous improvement of processes through design innovation,technology and knowledge management
  • Efficient after-sales service and dedicated team to fix troubleshooting

Client Appreciation Letters


The strategic or organisational level

  • In compliance with ISO 9001:2015, the Quality Manual clearly outlines the flow of control over the Quality Control System from the management to technical operations and support services.
  • Integration of ERP, implemented within the organisational level with QC & QA capabilities with documentation...

The tactical or functional level

  • Advanced manufacturing and testing facility maintaining practices like lean manufacturing to reduce waste & risk, enhancing operational resilience.
  • The in-house R&D facility is engaged in an extensive design and development process, in consideration of the needs of customers.

The manoeuvre or operational level

  • A hygienic and safe working environment is maintained on all workshop floors.
  • The working staff is given timely reminders of the QC protocol through SOP (Standard Operating Procedure) documents that detail all specific operations and methods.


Signotron has established in-house modern manufacturing & test facilities to work with.
Some of the major types of equipment related to Quality are:

  • Temperature Controlled Curing Chambers
  • Automatic Coil Winding Machine
  • Temperature Controlled Soldering Station & Reflow Soldering Machine
  • Power & Harmonic Analyser
  • High Voltage & Surge Comparison Tester
  • Induced High Voltage Tester AC
  • Dual Trace Storage Oscilloscopes
  • Distortion Meter
  • Regulated Power Supply with test bench
  • Infrared thermal imager
  • PCB Drilling CNC Machine
  • PCB Inspection Microscope Camera.

*** All the units mentioned above are being regularly checked and calibrated and certified as per ISO 17025 standard by NABL accredited labs.

Other critical tests like:

  • 5G Vibration test facilities
  • EMI / EMC test
  • Environment test
  • High Altitude test
  • Ingress Protection test
  • Multiple Environment Over Stress Testing (MEOST)

-are done through different government NABL accredited laboratory & institutions like ERTL, NTH, SAMEER & IIT.


ISO 9001:2015, the international standard specifying requirements for quality management systems, is the most prominent approach to quality control management systems. Key performance indicators that we follow are:

  • Meeting the customers' requirements: This is our first step in allowing our customers to understand our honest ways of work as they put their trust in us.
  • Meeting the organization's requirements: This ensures compliance with regulations and provision of products and services in the most cost- and resource-efficient manner, creating room for expansion, growth, and profit.
  • The robust design of individual products by our team of design engineers: We are connected to reputed professors and specialists from renowned universities like IIT (KGP), Jadavpur University & IIEST (Shibpur), for necessary design support and technical guidance.
  • Selecting the best brands for electronics components and procurement of all raw material through a genuine and tested source.
  • Testing of all finished products - as per customer specifications or I.S. before their final dispatch. Test reports of the same are recorded.

Our management aims to build an effective work culture with a positive approach towards work, high employee morale, measurable productivity and a strong focus on safety and health.


ISO, RDSO, RITES and private consignees conduct regular and frequent inspections.

There is also an intra-company provision for compliance with prescribed quality standards. This involves inspection at an individual component level to assess quality compliance with the originally required criteria. All parameter data is duly reported to the management. Deviations from prescribed standards are either corrected or eliminated at the first occurrence.

Client Appreciation Letters

contact us :


Signotron Tower Plot J1-6, Block - EP, Sector - V, Salt Lake Electronics Complex, Kolkata - 700 091




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