For this reason, the E-Four Voltage Power Optimiser has been designed with no moving parts or electronics: voltage optimisation and power quality improvements are achieved through the internal interaction of magnetic fields only; the E-Four unit is as reliable as the incoming power supply itself.

Over 300,000 units have been installed in Japan alone, without a single failure –the unit will last for the lifetime of the building – around 30-50 years.

Technical description

It is important to understand that the E-Four Voltage Power Optimiser is not an auto-transformer, and should not be confused as one.

E-Four’s Voltage Power Optimiser has three separate primary and secondary windings, with the primary winding carrying the load current, the unit also features a tertiary winding on each phase connected in a closed ‘delta’ configuration.

Uniquely, the technology unit uses magnetic interaction between the windings to deliver the savings and benefits.

The primary winding is constructed from copper sheets – with very few turns so the impedance seen by the load current is negligible, the primary winding incorporates the principles of a line reactor and therefore acts as a low pass, passive harmonic filter.

There is a connection between the secondary winding on each phase and its related primary winding, this connection creates a ‘differential compounding’ effect on the output voltage – this allows the unit to have a range of ‘tap’ settings (-4%, -5%, -6%, -7%, -8%, -9%, -10%, -11%,-12%) that reduce the voltage efficiently.

The reduction of voltage is achieved through ‘mutual inductance’ of the primary and secondary windings. In simpler terms the value of the voltage induced in the secondary winding is in direct proportion to the current flowing in the primary, so as the primary current rises - secondary voltage rises – and the reverse is true.

There is a direct connection between the primary and secondary winding, and because the secondary windings form a closed circuit, current will flow through the secondary windings due to the voltage differences between each secondary winding.

In addition to the voltage optimisation and phase balancing effects of the secondary windings, the unit also features a tertiary winding on each phase connected in a closed delta configuration. This is to provide a path to circulate and filter harmonic currents – therefore preventing them from circulating outside the load.