33kV On-load Tap
Changer TYPE–T12

OLTC Type T12 is a 3-phase, single compartment, externally mounted compact on-load tap changer of rating 33 kV 200A with 17 positions Linear. T12 works on the principle of high speed transition resistance and is suitable for both star and delta connected Transformers. T12 works on flag cycle, and is rated for bi-directional power-flow, max. through a current of 200A and step voltage of 850V.

Advantages

This compact design requires low maintenance.
The oil volume of 168 litres is an added advantage.
T12 has a unique plug-in terminal design for easy connection to the Transformer.
An electronic digital controller operates the motor instead of conventional hardware-heavy controls.
This electronic digital controller has a built-in Automatic Voltage Regulating Relay (AVR).
Remote operation is made possible, with an optional “Remote Operating Device"(ROD), eliminating an expensive RTCC. This ROD facilitates remote “Raise\Lower” operations.
The tap changer is protected by a pressure relief device provided on the top of OLTC. The Design has a free oil level which eliminates the conservator.
Adequate free space is provided in the tank above oil level. The oil level gauge on the side plate helps to ensure correct filling of oil.

Key Features

The switch chamber and the drive mechanism are separated by a metal sheet partition. The fixed contacts are mounted on lead embedded epoxy cast phase boards.
The moving contact slides on both sides of these fixed contacts and selects the tap.
The selector switch combines the functions of a tap selector and a diverter switch.
The drive mechanism has an energy storage device that releases the spring energy to drive the selector switch.