VARIAC Variable Transformers

VARIAC variable transformers, also known as variable autotransformers, are a type of transformer used to vary the output voltage of an AC power source. They are commonly used in applications such as testing equipment, lighting control, and voltage regulation.

The basic principle of a VARIAC transformer is to use a movable brush or wiper to tap into a single winding, allowing the output voltage to be varied between the minimum and maximum levels. The VARIAC transformer is essentially an autotransformer, meaning that the primary and secondary windings are connected in series, and the output voltage is a function of the position of the wiper along the winding.

VARIAC transformers are designed to handle high currents and voltages, and have a low leakage inductance and low output distortion. They are typically used in applications that require precise and continuous voltage control, such as motor speed control, heat treatment, and lighting dimming.

VARIAC transformers are available in various sizes and configurations, ranging from a few hundred watts to several kilowatts. They are designed to operate at frequencies of 50 Hz or 60 Hz, and are available in single-phase or three-phase versions, depending on the application.

Proper selection and use of VARIAC transformers are critical to ensure safe and reliable operation. They are subject to various standards and regulations, such as UL (Underwriters Laboratories) and CE (Conformité Européenne), to ensure their safety and performance. VARIAC transformers should be operated within their rated voltage and current limits, and should be properly grounded and protected from overloading and short-circuiting.