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Elsklo Ltd.
industrial furnaces and spare heating systems­

Bernard & Bonnefond VARIVOLT

VARIVOLT - regulating transformer

LV or HV primary voltage

Galvanic insulation between primary and secondary windings

Linear, on load voltage variation

No DC component

Friendly simplified interface with supervisory systems

100% custom made equipment

Efficiency higher than 98 %

High power factor

No addition of harmonics to the mains

Reduced sizes

Bernard & Bonnefond
Producer of regulating transformers VARIVOLT (France).

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Elsklo and Bernard & Bonnefond

Elsklo Ltd. is an exclusive representative of Bernard & Bonnefond for Czech Republic and Slovak Republic.
In cooperation with Bernard & Bonnefond we provide complete customer service - project preparation, installation of the equipment, commisioning, warranty and past warranty service, spare parts delivery and training.


VARIVOLT principle
1 - sliding contact
2 - slideways
3 - rotating core
4 - sec. winding
5 - colector

Significant product of Bernard & Bonnefond is the regulating transformer VARIVOLT, mainly used in glass industry as a furnace transformer for electric glass melting and boosting.
Other aplications are: metalurgy, chemical industry, testing facilities.

VARIVOLT principle

The core rotation drives the copper contacts along the secondary windings, allowing a stepless voltage variation. This sliding contact provides a continious connection between the copper slideways built in the core, and the secondary windings groove. The control system drives the cores in rotation through a moto and its reducer. Limit switches protect from owertravel.

Production program of Bernard & Bonnefond

  • regulating transformer VARIVOLT
  • low velocity alternators
  • high current lines
  • synchronous/asynchronous generators
  • reactors
  • engeneering

Industrial and laboratory furnaces · Heating elements production · Heating systems · KANTHAL · Electric equipment · Bernard & Bonnefond