On load Variable Voltage Transformer - from 200 to 30,000 kVA

Technical Performances

LV or HV primary voltage

Galvanic Insulation between primary and secondary windings

Linear, on load voltage variation


Friendly simplified interface with supervisiory systems

100 % custom made equipment


Cost savings

Efficiency higher than 98 %

High power factor

No addition of harmonics to the mains

Power delivered always adapted to the load

Reduced sizes


Magnetic circuit

VARIVOLT is a rotating core transformer.

The magnetic circuit consists of 2 flat bored yokes, and cylindrical rotating cores.

Cores are made of magnetic steel strips radially stacked around a shaft.

The cores are driven in rotation by an external motor. The cores are the only mobile parts.



Galvanic insulation is acheived thanks to separated primary and secondary windings.

The induction and the voltage per turn is constant, resulting in high efficiency and power factor.

HV or LV primary windings are in most cases standard.

LV secondary windings comprise a grooved copper conductor, allowing 0 to 100 % variation of the maximum secondary voltage.


Sliding contact

The sliding contact is made of special copper to facilitate high current transfers.

Helical mouvement of the sliding contact along the winding allows voltage variation without arcing.

The oil filled VARIVOLT minimises corosion of the sliding contacts and guarantees several years of maintenance free use.

Below : example of one Varivolt dwg (pdf)

video : how to change a water exchanger

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