TRANSFORMER TAP CHANGER DESIGN FOR MODERATE KVA AND CURRENT BASIC AND TUTORIALS

TRANSFORMER TAP CHANGER DESIGN FOR MODERATE KVA AND CURRENT BASIC INFORMATION
Notes On Transformer Tap Changer Design



Tap-Changer Designs for Moderate kVA and Current. In the smaller ratings, where both the voltage and the current are moderate, the energy to be ruptured in switching from tap to tap becomes relatively so small that light and simple equipments are feasible.

A variety of mechanical designs, together with special circuits, has been evolved with the purpose of providing simpler, smaller, and inherently less expensive equipments. The following may be noted:

1. Designing the tap changer so that it is capable of rupturing the current directly on the same switches which select the taps

2. Designing the circuit so that the tapped winding is reversed in going from maximum to minimum range, thereby securing a substantial reduction in the rating of core and coils for a given output

3. Using higher switching speed, by means of which the life of the arcing contacts is increased.


Tap Changers Designed to Interrupt Current. The contactors C (Fig. 10-27) operate to open the switching circuits so that there is no interrupting duty on the selector contacts which connect to the transformer taps.

When the rated current is moderate, it becomes possible to rupture the current directly on the tap-selector switches and thus obtain a major economy in the cost of the mechanical equipment.