AIR COOLED VARIABLE TRANSFORMERS ( VARIACS ) of Large Capacities say from 200 to 2000 Amps – have remained a Technological challenge in the Industry.

AIR COOLED VARIABLE TRANSFORMERS ( VARIACS ) of Large Capacities say from 200 to 2000 Amps – have remained a Technological challenge in the Industry. The basic issue is heating of Carbon brushes because the Brushes always move with two or more turns of Transformers, always shorting on the Copper Winding. In the basics of having uninterrupted Current flow, the Carbon Brush span has  not to leave the last turn without touching the next turn. Shorting of Transformer Turns through Carbon Brushes produce heat and tend to damage insulation of copper wire and to ultimate overheating and failure. To overcome heating damages at local points- use of these units in Oil filled tanks becomes a necessity. Use of Oil in Tanks have their own issues. In Green Building concept of latest Industrial Buildings – to save from Environment damages – oil is not permitted for use in such equipment.

Even history does not make you to forget that – one of the greatest Fire case in UPHAR CINEMA in Green Park one of the posh areas of Delhi was aggravated due to Transformer oil equipment installed in the Basement of Cinema hall that resulted in 59 Deaths on 13th June 1997.  Govt. issued guidelines banning use of oil filled equipment in Basements. Air Cooled Distribution Transformers came in vogue but for Voltage Stabilisers no good viable alternative was available.

1000 Amps/600 Volts
600 Amps Inside – Front & Back / 600 Volts
600 Amps/ 600 Volts
600 Amps/600 Volts

WE at Green Dot, are a 39 Years old manufacturing set up in Variable Transformers & Servo Stabilisers etc.  & have put substantial efforts in the R & D to develop High Capacity Air Cooled / Aided Air Units.  Having succeeded in developing, we have supplied Air Cooled units up to 1600 Amps in few GREEN INDUSTRIAL buildings. We are the only manufacturers of this product in the country. We have used Thermostatically protected coils that sense the temperatures of heat generating points and activate fans up to certain temperature range and cut of the supply if for some reasons the temperature touches the thresh hold point. In design – the coils are over rated and heat sinks are built in the coil below the winding & on Carbon Brush holding points of moving arms. In certain cases – even IP-54 Cabinets have been used with Air Filters for clean environments in side the cabinet. Even hooter is energised in ultimate stage of overheating and supply is cut off. ACB, MCB, MCCBs & Contactors  are used in the panel for Power control &r Cut Off functions.  A remote control panel is provided for operating the unit from distance. Micro Controller based cards have been used to Drive DC Motors with speed control for Inching use for FINE Voltage Control, LCD Input & output Voltage & current displays. Safety features of delays in operation of Low Voltage, High Voltage & overload, Auto Manual Control. In auto feature – the output adjusted voltage can be kept regulated to adjusted value.

The same units of 600 A or 1000 Amps.  can be used for manufacturing  Servo Stabilisers AIR COOLED  from 500 to 3000 KVA capacities.

Green Dot Electric Limited
G-9 Hemkunt Tower
98 Nehru Place
New Delhi 110019
Ph: 9810117725
email:[email protected]

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