Current Transformer for Current Measurement Experiment

Objective

The objective of this experiment is to demonstrate the use of a current transformer (CT) for measuring AC current in a circuit without breaking the circuit. This experiment will highlight the principles of electromagnetic induction and current measurement.

Required Components

Circuit Setup

This experiment involves connecting the current transformer around the conductor carrying the AC current to measure the current without directly connecting to the circuit.

  1. Connect the load (e.g., resistor) to the AC power source.
  2. Place the current transformer around the wire that connects the load to the power source, ensuring that the wire passes through the center of the CT.
  3. Connect the secondary terminals of the current transformer to the multimeter set to measure AC current.

Experiment Steps

  1. Turn on the AC power source to energize the load.
  2. Use the multimeter to measure the output current from the secondary terminals of the current transformer.
  3. Record the current reading displayed on the multimeter.
  4. Optionally, use a clamp meter around the same conductor to measure the actual current for comparison.
  5. Change the load to observe how the current transformer readings vary with different loads.

Analysis

Analyze the measurements obtained from the current transformer. The output current from the CT can be calculated using the transformer ratio. For example, if the CT has a turns ratio of 100:1, the primary current can be calculated by multiplying the secondary current by 100. Compare these values to those obtained using the clamp meter for accuracy.

Conclusion

This experiment demonstrates the principle of current measurement using a current transformer, showcasing how CTs can measure high currents safely by providing a scaled-down output. This technique is widely used in power systems and industrial applications for current monitoring and protection.