Current Transformers are devices, which convert high power signals to lower, more manageable signals. This transformer encircles the wire carrying the signal and via induction transmits a proportional signal through two leads attached to the secondary side. It is also intended to perform roles for safety protection and current limiting.

They can also cause circuit events to occur when the monitored current reaches a specified level.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 burden resistor connected across the secondary produces an output voltage proportional to the resistor value, based on the amount of current flowing through it. When choosing the burden resistor, the engineer can create any output voltage per amp, as long as it doesn't saturate the core.

This trainer is intended to study how the current transformer functions. With this it is possible to make measurements on the secondary by properly connecting the Burden resistor at the secondary. In order to accomplish this task the trainer is provided with a current transformer with maximum primary current of 1A and secondary current of 200mA for 1A input. Two independent current meters monitor both primary and secondary currents. In order to facilitate the loading of primary, a lamp load consisting of 300W is available. An external Variac ( Dimmer-stat) of at least 3A, is required to vary the input current.

At the end of the experiment, a graph depicting the primary Vs secondary current is drawn. Transformer losses are not considered at this stage.

Specifications:

• Primary current : 1A Max.
  
• Secondary current : 200mA proportional to the primary current
  
• Lamp load : 300W built-in
  
• Meters : 1A in primary side and 250mA at secondary
  
• Burden resistor : 5 Ohms
  
• Optional : Variac operating in the range of 0 to 240V AC @ 3A current rating.
  
• Enclosure : Instrument is housed in an ergonomically designed cabinet.