Contents

IEEMA Specifications for Instrument Transformers (Recommendations)   

Introduction

The instrument Transformer division of IEEMA undertook the exercise of formulating a standard for Instrument Transformers sometime in 1993 with a view to detail various aspects of Instruments Transformers. Members found it essential to 3eliminate misunderstandings between the manufacturers and purchaser and to assist the purchaser to select and obtain Instrument Transformers to meet his need at a minimum cost.

It has been observed over the years that in majority of cases, the purchaser over-specifies his requirements, just "to be on the safe side" thereby incurring avoidable extra cost. This standard, therefore, suggests the specifications, which are considered practicable for Instrument Transformers of reasonable dimensions and cost. It is however, clearly understood that the existence of this standard does not in any respect preclude any member or non-member from manufacturing or selling products not conforming to this standard. The list of member organizations contributing to the formation of these standards is appended.

In the formulation of this standard, assistance has been obtained from electrical consultant organizations as also from the user industries by way of detailed discussions to understand their requirements. . The matter has also been discussed with the Switchgear division of IEEMA to seek their views about a standard of this type. The instrument Transformer division of IEEMA is grateful to all such organizations who have, directly or indirectly contributed to the formation of this standard.

A complete revision of the "Indian Standard Specifications" for Current Transformers (I.S. 2705) and Potential Transformers (I.S. 3156) was published in 1992. This revision was developed by Bureau of Indian Standards Sub-Committee (E.I.D.C. 34). This standard is intended to supplement the Indian Standards and its not intended either duplicate or supplant it. It is believed that this standard is more specific in respect of the suggested ratings and dimensions of Instrument Transformers.