Continuously Auto Variable Transformer / Variacs
Variacs or variable auto transformer is a Continuously variable
voltage transformer, having a single layer winding on a toroidal core
of high grade Steel.
In an autotransformer portions of the same winding act as both the
primary and secondary winding. the winding has at least three taps
where electrical connections are made. One end of the winding is
usually connected in common to both the voltage source and the
electrical load. The other end of the source and load are connected to
taps along the winding. Different taps on the winding correspond to
different voltages, measured from the common end.
On one face of the copped winding, along the periphery, a special
durable contact surface is made. A specially designed carbon brush
slides smoothly on the surface. A contact arm holding the contact
brush is fitted to the central shaft and as the control knob is
rotated, the carbon brush slides over the winding and taps off a
portion of voltage across the winding.
Any desired voltage within the maximum range can be obtained by
adjusting the position of the brush. The calibrated dial reads
approximately the output voltage at no-load, when the input is at its
rated value. Rotation of the brush arm by manual of motor drive
delivers an output voltage from zero to or above line voltage.
Variable Auto Transformer, manufacturer by Apex Power Systems is the
most useful and effective device for step less, break less and continuous
control of A.C voltage and therefore, for control of various other parameters,
dependent on A.C voltage. It is ideal controlling device for numerous
applications in laboratories and in industrial & commercial fields.
The basic Auto Transformer is meant for operation off a nominal
voltage of 240 V A.C & can give output voltage anywhere between 0 –
240 V or upto 290 V, by a simple transformer action. Three such
Variable Auto transformer when connected electrically in star &
mechanically in tandem, became suitable for operations of 415 V 3
Phase A.C. supply & to give output of 0 – 415 V or upto 470 V.
Rating Available :
2 Amp to 1800 Amp
Air / Oil Cooled and Single / Three Phase
(Special ranges also available on request)