An instrument transformer that measures the AC current drawn by the elevator motor, providing feedback to the drive and protection system.
Full Definition
The current transformer (CT) in an elevator installation steps down the high primary current of the motor supply to a measurable secondary signal (typically 0–5 A or 4–20 mA) for use by the drive controller and protection relays. It enables motor overload protection, torque monitoring, and energy metering. CTs are rated by primary current, accuracy class, and burden. In modern VFD-driven elevators, current measurement is often performed internally by the drive; standalone CTs are more common in older star-delta or two-speed motor installations.
