The control transformer is a step-up or step-down isolation transformer, and also a multi-tap transformer that has multiple taps on either the primary winding or the secondary winding. It is a small dry-type transformer designed to supply stable voltage to control circuits and equipment, typically operating in AC 50Hz or 60Hz circuits with voltage ratings of 1000V and below. These transformers are engineered to handle momentary current inrush caused when electromagnetic loads such as contactors, solenoids, timers, and relays are energized at startup, providing the secondary voltage stability required during these transient periods. Available in power ratings from 500 VA to 10 kVA, control transformers feature multiple input and output interfaces—such as 240V to 110/36/24V, 220/380V to 120/48V, or 440/460/480V to 120/24V configurations—allowing them to obtain appropriate voltages for various applications while changing AC voltage and impedance. When operating within design power limits, they can also change current levels, and they provide anti-interference functionality in different environments. The working principle relies on electromagnetic induction, where alternating current in the primary coil generates an alternating magnetic field in the iron core, inducing an electromotive force in the secondary coil. These transformers utilize high-quality materials including pure copper or aluminum core wire for excellent conductivity and low temperature rise, silicon steel sheets as the iron core for strong magnetic conductivity, metal brackets for improved protection levels, and cold-pressed terminals for reliable wire connections.