Variac

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Photo represents example of series. See datasheet for more details on any specific model.

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Variac Selection Guide

To find the right model for you, please select:
(After selection, click the blue text below to pull up a model)

IET Labs offers over 500 different Variacs from Staco and General Radio/Technipower. To find the best Variac model for your application use the selection filter above.


Please be aware that not all combinations are available and for example are looking for a Variac with current rating of 5 A and nothing comes up with your other limitations try a current rating of 7 A.

For detailed specifications on any Variac model, search the model number in the search bar above. "171" or "5011-3P"  Then you can see the relevent datasheet.

Unlike most transformers, the Variac has a transformation ratio that can be smoothly and continuously changed so the output of the unit can be controlled from zero to line voltage or even higher. Because it is a transformer, the Variac is

  • efficient transforms power more efficiently than rheo­stats
  • durable because it runs cool
  • overload-able withstands 1000% short-term overloads
  • independent of load size or power factor voltage to the load changes little from full load to none
  • quiet adds no noise or distortion to the line
  • reliable exclusive Duratrak® contact surface prevents injurious high-temperature oxidation and resultant brush-track deterioration

In addition, the Variac is

  • easy to install. All mounting hardware is included; wiring diagram is on the terminal plate; conduit knockouts are included on all enclosed models.
  • available in hundreds of standard versions to satisfy line frequency, voltage, and phase requirements, load size, mounting demands (including portable and metered models). They can be supplied with motor drives, ball bearings, and in ganged assemblies to increase basic line-voltage and load-current ratings.
  • assured safe by Underwriters' Laboratory listing and Canadian Standards approval of many models
  • available in militarized models specifically designed for 400-Hz operation


The Variac® autotransformer is an efficient, trouble­free device for controlling ac voltage and any other quan­tities that derive from ac voltage: heat output, light in­tensity, motor speed, and the outputs of various power supplies.