A current transformer or CT is a special purpose instrumentation transformer. In this post, you’ll learn the working and applications of the current transformer.
List of Contents
What is Current Transformer
A current transformer is a special type of transformer which produces a lower current at the second terminal which is proportional to its input current. For example, a transformer with 100:5 will step 200 A current to 10 A. They are also known as protection or instrumentation transformers.
A CT always connects in series with the circuit and is available in large variants. Let’s first understand the working of the current transformer.
CT as Instrumentation or protection transformer (Applications)
Many times we need to measure the current of higher orders such as 500 A or 200 A. A normal instrument such as ammeter has the limitation of 10 or 20 A. In such cases, we can connect the ammeter with CT to measure the current. In such case, it is referred as the instrumentation transformer. The relays and other instrumentation equipment also have their limitation in handling currents. A CT acts as protection transformer and steps down current to the safe lower voltage level, In this case, it is referred as protection transformer.