transformer home » Transformer
Articles » An introduction to Current
An introduction to Current Transformers
Many of us do not know the purpose
of current transformer. A current
transformer is kind of electrical instrument
that is produced particularly to provide a flow of current
in the secondary circuit that is properly perpendicular
to the amount of current flowing in its primary circuit.
It actually measures alternating current flowing by
way of a conductor. As it is used to measure current,
a current transformer is normally classified as a kind
of instrument transformer. It could also measure the
voltage drop across any known resistor. This could be
applied for a low current application but is often impractical
for high current applications. The resistor consumes
more power (decreasing efficiency) unless the resistor
is extremely low in value, in such case there might
be very little voltage the measure. The resistor can
also be very large. The resistor's heat might affect
the resistor value, so reducing accuracy of its measurement.
A current transformer could accurately
calculate the alternating current and put out a reasonable
voltage that is proportional to the current, but it
is without as much heat and size that an appropriate
resistor may require. The current transformer could
perform its function with extremely little insertion
loss into the conductor current is been calculated.
A current transformer as well offers voltage isolation
among the conductor and the measuring circuitry. Proper
function of a current transformer wants use of a load
resistor. And load resistor is normally referred as
to a "burden resistor".
The most excellent core structure for
a current transformer in way of electrical performance
is a toroidal coil. Many toroidal
current transformers normally have only one winding.
This winding is generally a "high turns" winding that
functions as the secondary winding. In application,
the toroidal current transformer is fallen over an end
of a high current wire or buss bar that further conducts
the primary current.
Split core current transformers are
especially planned so that they could be gathered around
a buss bar without cutting off the buss bar. "C"- cores
and "U" core structures are normally used for split-core
current transformers as they are comparatively simple
to take apart and put back together across the buss
bar. Traditionally, this has not been realistic for
toroidal coils, but there are presently some supple
toroids that allow the "split-core" feature of installing
it around a buss bar. They have restricted application.
Some printed circuit board applications would use bobbin
wound current transformers with two or more windings.