Vintage General Radio 3 Phase Variac Variable Transformer 9"

Description

Vintage 20th century three phase variac / variable transformer.

"From 1934 to 2002, Variac was a U.S. trademark of General Radio for a variable autotransformer intended to conveniently vary the output voltage for a steady AC input voltage. In 2004, Instrument Service Equipment applied for and obtained the Variac trademark for the same type of product. The term variac has become a genericised trademark, being used to refer to a variable autotransformer. " (Source: Wikipedia) "A transformer provides electrical isolation and impedance matching, and, in the application we’re considering here, translates voltages between primary and secondary circuits. In operation, alternating current at one voltage is applied to the primary side of the transformer yielding alternating current in the secondary side of the transformer at a different voltage. A transformer consisting of only one coil which is shared by the primary and the secondary side of the circuit is known as an autotransformer. A variable autotransformer is known generically as a Variac... The ratio of the primary to the secondary windings is variable, which means that the ratio of the secondary voltage to the primary voltage is variable. Some people use variacs to bring long dormant electronic equipment back to life gradually. Variacs are also used in experiments and testing to simulate various voltage and line conditions." (Popular Science)

Condition

Good Overall - Gentle wear

Dimensions

4" x 3" x 9" (Width x Depth x Height)