Current Transformers (CTs)

Function: Measure alternating current (AC) by transforming high primary current to a lower, measurable secondary current.

Key Features:

• Isolates measurement circuits from high-voltage systems
• Secondary current typically 1A or 5A at full scale
• Must never operate with open-circuited secondary (risk of high voltage)
• Used in metering, protection relays, and monitoring systems

Applications: Power systems, energy meters, protective relaying, industrial control.

Installation Tip: Always short-circuit secondary before disconnecting from load.