Welcome To Spectanet

      We are experienced and professional company based in Bangalore providing Overhauling and Repair of NGEF TRANSFORMER OLTC -30 KV to 220 KV, NGEF OLTC Motor Drive Wiring, NGEF OLTC Control Gear, Repair NGEF OLTC Reduction Gear Assembly, NGEF OLTC Driving Mechanism, NGEF OLTC Selector Switch And NGEF OLTC Diverter Switch 200A to 1500A.

       We also provide complete NGEF OLTC spares like complete NGEF Diverter Switch,complete NGEF Drive Motor Box,fixed, moving contact-ngef transformer oltc-on-load-tap-changers, braids, gear box, fibre cylinders for Flange Type And Fork Type, transition resistance, ‘o’rings, oil seals, gaskets suitable for NGEF ,Trafo-Union ,AEG AND MR GERMANY make OLTC’s.


  • Maintenance of on load tap changers(NGEF ,TRAFOTECH ,AEG AND MR GERMANY make OLTC’s).
  • Overhauling of In-Tank & Flange mounted OLTCs.
  • Diverter Switch Overhauling.
  • Motor Drive Panel Overhauling and Rewiring.
  • Fault diagnosis & solutions.

NGEF OLTC Diverter Switch

  The NGEF OLTC diverter switch employs “flag cycle” system of operation. For each phase they have two main contacts, two switching contacts and two resistor contacts. Transition resistance is connected in connected in series with resistor contact and are important because they ensure that he load current is transferred from one tap to other without interruption. Read More….


      The selector switch is mounted on the bottom plate of diverter switch tank submerged in insulating oil of transformer. The tap selector has two circuits per phase, in which one carries current in each tapping position. The moving contact of the selector enables the non current carrying circuit to be connected to the next upward or downward tap. The moving contacts are operated through geneva gear. The current is switched to the next tap by snap action diverter switch.

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      The motor drive mechanism is mounted externally on the transformer tank and is connected to the on load tap changer by shafts, worm gears and bevel gear. The OLTC can be operated electrically through motor drive panel using contactors and limit switch and manually hrough motor drive mechanism.

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      We manufacture and supply superior quality Silica gel breather for transformers with different flange sizes and capacity as required by the customers at best prices.Our company manufactures Silica gel breather which is attached to the transformer conservator tank outlet when air flows in and out of the conservator during breathing process the moisture in the air is absorbed by the silica gel crystals letting only clean and dry air into the conservator.The dust particles in the air gets settled in the oil cup provided at the bottom of the silica breather.Thus protecting the insulating and dielectric property of the transformer oil.

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