Ferroamp Elektronik AB

Adaptive Current Equalization technology (ACE)


Three phase power reinvented Ferroamps patented Adaptive Current Equalization technology (ACE) allows for a more efficient use of a three phase supply. EnergyHub ACE transfers energy between the phase conductors to increase the headroom between the mains fuse rating and the loads. This headroom can either be used to reduce the mains fuse rating or to increase the load, for example more efficient and faster EV charging.

  • Mains fuse overloading avoided
  • Single phase load currents can exceed the current rating of the three phase supply
  • Reduced distribution losses
  • Simple installation
  • Transparent to existing loads
  • Prevents over currents from all loads in the installation

The ACE technology dynamically transfer energy between the phase conductors of a three phase installation, thereby limiting supply phase currents to the mains fuse rating without limiting the load currents. The supply phase currents are measured using current transformers and a device based on the Current Equalizing Technology will absorb energy from phase conductors that have currents below the mains fuse rating and inject energy into phase conductors that have currents exceeding the fuse rating.


Traditionally, load shedding relays have been used to prevent overloading of the mains fuses. Load shedding relays sense the supply currents and disconnects one or more preselected loads if the total current exceed the mains fuse rating. Besides the inconvenience of disconnecting loads, load shedding relays require careful planning of the phase balance and selection of loads that can be disconnected. Further, load shedding relays works poorly when a large degree of plug connected equipment is used as these can appear on different phase conductors from time to time.

These problems can be solved with the Current Equalizing Technology. Similar to the load shedding relay the current equalizer sense the supply currents, but instead of disconnecting loads during over current situations, energy is instead transferred between the phase conductors and the supply current is limited. The current equalizer utilizes the fact that domestic electrical installations today are dominated by single phase loads and often has a large degree of asymmetry between the three phase conductors. When an over current occurs in one phase conductor there will still be headroom in the remaining two phase conductors.

The current equalizer does not need any information about which loads that exist in the installation, thus the current equalizer is completely transparent to the existing loads. As a result installation is very simple since the existing installation need not be modified. The current equalizer is simply installed as a new three phase device.

The increased headroom provided by the current equalizer can either be utilized to reduce the mains fuse rating or to increase the load currents without increasing the fuse rating.


Electric vehicle (EV) charging will present a rather new type of load behavior to domestic electrical installations in that a large single phase load is supplied continuously for several hours. This new type of load in combination with the existing loads is likely to overload a mains fuse in many installations. Thus, larger mains fuses or even larger supply cables can be required, if at all possible, to enable fast charging. This problem can however be elegantly solved for electrical installations with a three phase supply.

In addition to ensuring that the mains fuses are not overloaded, the Current Equalizing Technology will even allow single phase loads to be supplied with a current exceeding the rating of the three phase supply. For example, in electric vehicle charging applications, a single phase EV charger could be supplied with 32 A current in an electrical installation with a 3 x 20 A three phase supply.

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