Single Phase Variac

A variable auto transformer provides continuously adjustable AC voltage. In it’s Auto transformer form it is an efficient, reliable method of controlling AC voltage from zero to line voltage by amplitude modulation of the AC waveform. Since the current, power, heat, light and motor speed are further functions of the voltage, the Dimmer Dot Variable Transformer finds its varied use, but is not designed to provide AC mains isolation.

Air cooled – single and three phase:

Air cooled units are a cost effective, trouble free device to provide continuously adjustable voltage for AC supply equipment.
Air cooled units are light weight and easily transported. When used correctly they give many years of reliable service.

SALIENT FEATURES:

The Variable Transformer, consists of a single-layer winding on a toroidial silicon-steel core. As the control knob is rotated, a carbon brush traverses the winding, tapping off a portion of the total voltage across the winding. The brush is in continuous contact with the winding, and the voltage between turns is always less than 1 volt even in the largest model. In the smallest model it is only about 0.3 volt. The discrete voltage increments obtained as the knob is rotated are always less than the voltage between turns. Since the brush spans more than one turn, the change in voltage is practically continuous. The brush is so designed that excessive heating cannot occur in the turns that it spans. Dimmer Dot has many operating advantages over any other manually operated voltage control devices for alternating current use

Air cooled versions are available in either:

Portable / Bench top (P) which are designed to sit on a bench or floor.

They are enclosed in a protective square casing with convenient carry handles for easy transport.
New square shape design enables easy mounting of external equipment, such as mounting blocks for GPO’s, etc.
Single Phase units have Rubber feet while Three Phase units have ball transfer units or steel feet.
Single Phase units can be rear mounted in an electrical enclosure, simply by removing the rubber feet.
Single Phase units up to 15 Amp have an AC flexible cord only, fitted.
Open back / Panel mount (OB) which are designed to be mounted behind a panel for easy installation into electrical enclosures, where only the support bolts and control knob are protruding.
Single Phase units can be rear mounted in an electrical enclosure, simply by removing the rubber feet.
Single Phase units up to 15 Amp have an AC flexible cord only, fitted.

Open back / Panel mount (OB) which are designed to be mounted behind a panel for easy installation into electrical enclosures, where only the support bolts and control knob are protruding.