SELECTOR SWITCH DRIVE MECHANISM TERMINAL BOARD 132KV TAP CHANGER TYPE ABS 132 ABS132 OLTC is a single compartment externally mounted on load tap changer. This OLTC works on the principle of high speed transition resistance and is applied at the neutral end of three phase, star connected transformers. The tap changer is equipped with a change over switch and will therefore suit either reversing or coarse fine type tapping equipment. The OLTC follows the principle of flag cycle thus making it suitable for bi directional flow of power. It has a maximum current and voltage ratings of 300A and 132kV respectively and it may be used on transformers up to 70MVA. There is provision for a maximum of 17 positions when connected with a change over switch. The compact design, with low oil requirement adds advantage to this tap changer. The complete tap changer unit with the drive mechanism and the selector switch chamber are housed in a sheet metal enclosure, with a flange for mounting on the port on the transformer tank. The selector switch chamber and the drive mechanism are separated by a metal sheet. The fixed contacts are mounted on the phase boards. The selector switch, one for each phase, moves over these fixed contacts and selects the tap. The selector switch comprises a main contact and two auxiliary contacts and combines the functions of tap selector and a diverter switch. The drive mechanism is coupled to the selector switch by drive shafts and series of gears. It comprises a motor reduction gear, dial switch for tap position indication, limit switches for stopping the motor at end positions, operation counters, and hand drive for emergency operations. It also has an energy storage spring whose sudden release of energy operates the selector switch. MOUNTING ON TRANSFORMER : The tap changer is mounted on the transformer by taking out leads via the epoxy cast terminal board of the tap-changer, which is a part of OLG supply. PROTECTIVE DEVICE : The tap-changer is protected by an oil surge protective relay (OSR) which is connected to a conservator. Though an OSR is supplied with the tap changer, the conservator and transformer oil are not part of our supply. A pressure relief device can be provided in addition as per customer requirements. TECHNICAL DETAILS CONSTRUCTION DETAILS