Variable Auto Transformer will be having round Toroidal Core made from CRGO Lamination duly annealed to reduce the iron Losses and for the good regulation as voltage drop on load is low due to low resistance of conductor & low leakage flux of toroidal core. Toroidal core will provide stepless, beakless, smooth continuous control linearly proportional to angular rotation. Toroidal core is having high efficiency as no load and full load losses are very low and negligible wave from and power factor distortion due to simple transformer action and excellent short time overload capacity. As Toroidal core is having no sharp edge the breakage of insulation and copper wire can be prevented. the toroidal is wound from metal tape wound on to a mandrel under closely controlled tension, then annealed and treated to develop fully the required magnetic characteristic. It has low electrical resistively, no hysteresis loss, a completely linear B-H Curve and an infinitely high saturation points. this permits the easiest direction of magnetization to be utilized.

  • Input : 240 V
  • Output : 0 to 270 V
  • Capacity : 2A to 500A
  • Type : Open or Closed
  • Cooling : Air Cooled or Oil Cooled
Three Phase
  • Input : 415 V
  • Output : 0 to 470 V
  • Capacity : 2A to 500A
  • Type : Closed
  • Cooling : Oil Cooled

Three Phase
Double Wound Buck-Boost Type Series Transformer:
Buck-Boost type series transformer is made from CRGO Lamination to minimize iron losses. Coils of Buck-Boost Transformer are wound with electrolytic grade copper to minimize copper losses for better efficiency of the units.

Carbon Brushes:
The carbon Brushes which make contact with and carry current from the uninsulated portion of the winding is made of high grade. It is capable of withstanding a minimum of 10,000 operations under the specified test conditions.

Temperature Rise:
The temperature rise of the Transformer winding and core is in accordance with IS 2026 (Part-2) : 1977. The Unit is designed for maximum 45-50 degree temperature rise at top of oil.

The core is made from low loss Cold-Rolled Grain Oriented (CRGO), annealed laminations of Electrical Sheets steel confirming to the latest International standards. Special frames structure is made for clamping the core to reduce the magnetic noises as well as making the whole structure rigid and robust.

Coils are wound with electrolytic grade copper strips or synthetic enamelled copper conductors. The coils are dried in electric oven and cooling ducts are provided to keep the temperature as low as possible to ensure high short circuit strength rigid connection support and proper clamping is provided.

Precompressed board and imported insulation paper of best quality is used.

Mineral Oil which comply with IS:335:1953 & Tested for resistivity, dielectric and acidic characteristic & duly filtered is recommended.

Tanks & Paints:
The tanks are made from M. S. Steel Sheets. Structure is given a primary coat of Epoxy primer and finishing coat of Epoxy paint.

Meters and Control System:
Standard quality meters and control panel accessories are used.

Terminal Box:
Proper size bus bar terminals are provided for input & output connections with earthing bolts at the two ends.

Electronic Voltage Sensing Control Card:
With high efficiency reliable IC's and triacs version sensing control card (Glass Epoxy) along with cared replacement facility Jig for fast response and correction will be provided. No relays i.e. No Moving parts are used to sense the A.C. Synchronous motor for the smooth operation.
Leakage flux is small compared with that of other types of cores
External field is small compared with that of other types of cores
Interfering fields tend to cancel in a toroidal core with compared to other