Control Transformers

A control transformer is an isolation transformer that provides good voltage regulation, and is also designed to provide a high degree of secondary voltage stability (regulation) during a brief period of overload condition (also referred to as “inrush current”). Control transformers are also known as Machine Tool Transformers, Industrial Control Transformers or Control Power Transformers.

Control Transformers are useful where the available voltage must be changed to accommodate the voltage required by the load. For many electrical circuits, the National Electrical Code (NEC) requires a separately derived neutral secondary connection provided by Delta-Wye connected transformers.

Transformers are manufactured in a variety of choices to meet many applications. Dry-type transformers are offered encapsulated, ventilated or non-ventilated, 600 Volt Class, isolation type, single and three phase, through 500 kVA. Indoor and outdoor models are an option.

General purpose transformers can be located close to the load. No vaults are required for installation and no long, expensive feeder lines are needed. Common applications include inductive and resistive loads such as motors, lighting and heating.

Control Transformer Applications

Control transformers are available in a variety of primary and secondary voltage combinations from 120/240 primary voltage, 24 secondary voltage at 50/60Hz through 480 primary voltage, 240 secondary voltage at 50/60Hz up to 5000 VA rating.

Typical Control Transformer applications may include:

  • Hospitals
  • Office Buildings
  •  Industrial Plants
  •  Schools
  • Commercial Buildings
  • Shopping Centers
  • Apartment Buildings
  • High Rise Buildings
  • Institutional Buildings