Price lists
On stock
Select a category:

Toroidal single-phase

Toroidal three-phase

Accessories and options
Home › Products › VariacsStatics

Static Variacs


  • Voltage input : single-phase 230 Vac or three-phase 400 Vac + N
  • Output : single-phase from 0 to 250 Vac or three-phase 432 Vac + N
  • Frequency 50/60 Hz
  • Mains galvanized isolation
  • Resolution 0,98 V single-phase, 1,7 V three-phase
  • Voltage regulation on any power rating
  • Stabilizing precision on max. rating ±1% 
  • Ambient temperature -10 + 40°C
  • Wave distortion < 0,01 %.
  • Unaffected by power load factor
  • Resistant to surge overloads 5 In. approx.
  • Efficiency from 91 to 98 %

Static power control

To vary AC power from zero up to a preset value statically, without introducing wave distortions and maintaining a stable value, is now possible with Digivar !
VDR/2000.XXX and VDR/3000.XXX Families, single and three-phase, now represent the most innovated Variacs on the market.
Using the same base principle of Digistab stabilizers, we have now designed a Variac with a resolution of 8 bit, which can start from zero volt and reach the output power or a higher value.
What are the advantages of a Static electronic Variac vs. the traditional toroidal or column type with brush withdrawal ?
The most obvious advantage is the absence of moving mechanical parts, which can wear down with time.  The second and not less important point is the absence of  withdrawal parts: the traditional  brushes which assured an electric contact have now been substituted with graphite brushes, which have a high electric resistance and short circuit, thus avoiding high current circulation. This resistance, which is very important for perfect functioning of the electromechanical Variac, could cause a power fall from empty to load and a power loss, which would cause over heating that would ruin the brushes.
This does not exist in these Variacs as the power is obtained by a micro step type static system.
These Variacs feature a mains galvanised isolation, which isolates the system and made secure for those who have to use it;  the secondary has a very low voltage. One can use 6 bit, which would permit a continual resolution 0,23 V
How do VARAT's Variacs work ?  They are mainly made up form a series of generators with a 50% decreased nominal power up to 256th, all connected in series.
The lowest power step is of 1 volt and this is also the step with which the power will be converted from zero to the maximum.  
When the Variac reaches the requested power value, with a keyboard or other optional signals, it stabilizes and maintains the power, depending on the load.
The Variac's precision is determined by the smallest step, in this case 1 V, whatever the output voltage is.  If it is working at 230 V, we will have 0,4%, and at 110 V, 0,9%.
The precision, silence and reliability are only some of the high points, along with the possibility in controlling the device with digital systems, like PLC or PC.  It can also be used with the keyboard supplied.
The Variacs belong to the new generation of machines and are the perfect answer against pollution.

Catalogue download in PDF:

- Digivar catalogue

VARAT s.r.l.
Via della Tecnica 561/567 - 41058 Vignola (Mo) - Italy
Tel. +39.059.775677 - Fax +39.059.763696 - E-mail:
Copyright © 2004 Varat srl - All rights reserved