Wound Primary Current Transformers

Current Transformers can be classified into two types depending on the construction of the primary winding.  In bar type current transformers which are more common.  The conductor over which the current transformer is mounted also serves as the primary winding.  Thus the bar type current transformer has only the secondary winding.

In the Wound Primary current Transformer, the primary winding is also constructed inside the current transformer body.  The primary winding is usually of a single turn.  Wound Primary Current transformers are used in applications which require small current transformation ratios.  They are more accurate and have a higher burden capacity.  The wound primary is usually designed with toroidal cores for high efficiency. 

These current transformer are used in High Voltage applications