Shop control transformers used to supply lower-voltage power to industrial control circuits, machinery and automation equipment. Common connected loads include contactors, motor starters, relays, solenoids, pilot devices and other electromagnetic control components.
Compare control transformers by primary and secondary voltage, VA rating, frequency, winding material, construction and enclosure. Selection should account for both the continuous control-circuit load and the temporary inrush demand created when electromagnetic devices energize.
A control transformer supplies the voltage required by a machine or industrial control circuit. These transformers commonly power contactor coils, motor starters, relays, solenoids, timers, pilot lights and other control components.
Control-transformer sizing must account for two different demands: the continuous sealed load after the connected devices are energized and the temporary inrush load required to pull in contactors, relays and solenoids. A transformer that supports the steady-state load may still be undersized if it cannot provide sufficient voltage during the initial inrush period.
Open-style transformers are commonly installed inside control panels or enclosures that provide the necessary environmental protection. Encapsulated transformers enclose the windings and core in a protective compound and may be preferred where moisture, dust or contaminants are a concern. The complete installation must still meet the environmental and enclosure requirements of the application.
