akm comemde faxolif



The main characteristics of this new series of tap changers are:

  • Speed of installation
  • Speed of movement
  • Correct positioning after each tap change
  • Compact size
  • Self adjusting (within the design range) to the thickness of the transformer tank cover

This series is suitable for use in mineral oil or silicone liquid filled transformer. There is no need for washers during assembly because the tap changer adjusts itself according to the thickness of the transformer tank cover. Oil tightness is provided by O-rings. Tap Changers are available in standard types or custom made designs.

The Structure and Materials

The Fixed contacts are mounted on one of the two parallel insulating plates perpendicular to the support. The other moveable plate are mounted with the sliding contacts. The fixed plate is screwed to the support. The other moveable plate slides on the support using a rotating gear fastened to the shaft.

Fixed contacts are made of copper with the following inside diameters:

  • f = 2.1 mm for 10A rated
  • f = 3.1 mm for 30A rated
  • f = 5.1 mm for 60A rated

Conductors coming from the coils are crimped onto the copper tubes. If they are soldered, care must be taken not to damage the insulation. Mobile contacts are made of brass. Metal parts are made of corrosion-proof materials. On request all metal parts may be made of stainless steel. The other elements that compose the tap changer are made of polyamide reinforced with glass fibres. The insulating plates are made of premium quality phenolic resin. An aluminium alloy knob protection kit may be furnished upon request (optional).

Technical Specifications

Two voltage classes are available:


Voltage to ground
(According to IEC 214 and
CEI 14-10 Standards)
Power freq.
50/60 Hz
BIL 1.2/50 ms
kV kV kV kV
20 24 50 125
30 36 70 170

Three current ratings are available:

10A 30A 60A


The tap changer have undergone testing at CESI labs in accordance with IEC 210 and CEI 14-10 Standards:

  • test of resistance to short circuit current;
  • test of overtemperature limits;
  • seal test at standardized atmospheric pulse (1.2/50ms);
  • dry seal test at industrial frequency (50Hz).

Typical Model for Single-Phase Pawl Adjustment Off-Load Tap Changer(TCC MS-SA):

  • 20kV and 30kV
  • 10A, 30A and 60A
  • from 3 to 7 positions
  • 2.5% adjustment per position

Typical Model for Three Phase Pawl Adjustment Off-Load Tap Changer (TCC TS-SA):

  • 20kV and 30kV
  • 10A, 30A and 60A
  • from 3 to 7 positions
  • regulation 2.5% per position
  • or connection