Electronic Electrical Devices | Instrument Transfomer Companies
The instrument current transformer (CT) steps down the current of a circuit to a lower value and
is used in the same types of equipment as a potential transformer. This is done by constructing
the secondary coil consisting of many turns of wire, around the primary coil, which contains only
a few turns of wire. In this manner, measurements of high values of current can be obtained.
A current transformer should always be short-circuited when not connected to an external load.
Because the magnetic circuit of a current transformer is designed for low magnetizing current
when under load, this large increase in magnetizing current will build up a large flux in the
magnetic circuit and cause the transformer to act as a step-up transformer, inducing an
excessively high voltage in the secondary when under no load.