What is the main purpose of a control transformer in a motor starter?

The main purpose of a control transformer in a motor starter is to provide power to the control circuit. Control transformers step down the voltage from the supply to a lower voltage that is suitable for controlling devices such as relays, contactors, and control switches. By doing this, they ensure that control circuit components operate safely and effectively without the risk of high voltage supply impacting their performance.

Control transformers typically have a secondary winding designed to output a much lower voltage, commonly 120V or 24V, which is much safer for handling in the control circuit. This design also isolates the control circuit from the higher voltage motor circuit, providing an additional safety barrier for operators.

By understanding the key function of control transformers, one can see their critical role not only in ensuring the correct operation of control devices but also in enhancing overall safety in industrial electrical systems.