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ABS III 200 DELTA 72 is an On Load Tapchanger suitable for application at any locations of 66kV, Three phase, Star or Delta connected Transformers. It is a linear gear which suits a potentiometric tapping arrangement, with a Wander Lead. The tapchanger has a maximum of 17 positions, so that it can be applied to a winding of 16 taps, to give 17 different voltages. The functions of the Tap Selector and Divertor Switch are combined in one Selector Switch. The Selector Switch and its integrally mounted stored energy type Driving Mechanism, are housed in a sheet steel tank, with a Flange suitable for mounting on a port on the Transformer Tank. Leads can be brought out of the Transformer through a Port Flange mounted, oil tight, Terminal Barrier Board, which is part of the Tapchanger Supply. The Tapchanger must be connected to a conservator, through an Oil Surge Protective Relay. The Oil Surge Protective Relay forms part of Tapchanger supply, but the conservator and Transformer Oil are not in the scope of supply. The Tapchanger must be filled with oil by the Transformer manufacturer.


Rated Voltage                              : 66kV
Max. System Voltage                        : 72kV
Number of Positions (Max.)                 : 17 
Max. Continuous Current                    : 200A.
Number of Phases                           : 3
Max. Operating Step Voltage                : 1000V
Max. Operating Voltage over tapping  range : 20000V 
Max. Continuous Voltage to ground          : 72000V
Max. Continuous Voltage between phases     : 72000V
Time per tap change                        : 4-6 secs.
Wt. of Tapchanger without Oil              : 600 kgs.
Wt. of Tapchanger with Oil                 : 1430 kgs.
Oil Content                                : 980 lts. (approx.)
Transition Switching time                  : 30 Milli Secs.


                              Power Freq .    Imp. Voltage  
                              for 1 Minute    of 1.2/50 Microsec 
                              (kV RMS)        Wave (kVp).
Between Phases                  140               350
Tapchanger to earth             140               350
Between Adjacent Contacts       20                70
Across Tapping Range            80                200


This Tapchanger has been Type Tested to IS 8468 (equivalent to IEC 214) at CPRI., and at the Division of High Voltage Engineering, Anna University, Madras.

As part of our Quality Assurance Programme, we conduct several tests at our Works, in a routine manner before despatch. The main test, which goes beyond the requirements of IS 8468, is an operation test for 5000 operations, without the contacts energised. During this test, the Motor is run at its normal voltage, and speed, and is switched on and off for each tap change. This is a very rigorous, and very practical test from the point of view of the user. Tanks are Leak Tested at an air Pressure of 1Kg/cm2. Tanks are Sandblasted before painting.

We conduct the following Routine tests:

(1) Megger.

(2) Contact Resistance.

(3) Timing of Contacts.

(4) Aux. Circuit 2kV Withstand.

As the design and manufacture of our equipment are subject to constant improvement, the product supplied may differ in certain details from the specifications and illustrations.

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