The use of fans loaded on board diverse types of aircraft, and notably on board airplanes is known.
Generally, the fans loaded on board are used for cooling various loaded pieces of equipment such as for example on-board computers or other devices fitting out the aircraft. Other loaded on-board fans contribute, as an illustration, to the recirculation of air in the cabin of the aircraft.
For this, the aforementioned on-board fans include a rotary electric machine powered by an electric power supply network which is part of the aircraft. The fans also comprise a ventilation wheel secured to the rotor of the rotary machine. The fan wheel is for example formed with a propeller and is positioned in an air conduit opening onto the outside of the aircraft.
The use of on-board fans with an alternating current power supply with variable frequencies is also known.
Such fans are generally connected to the electric power supply network providing a three-phase current by means of a three-phase rectifier self-transformer. A rectifier self-transformer gives the possibility of transforming the three-phase electric network into a DC current network guaranteeing standardized harmonic rejection on the network.
A self-transformer is a transformer for which at least two windings have a common portion. The three-phase self-transformer usually includes a same magnetic circuit in a ferromagnetic material for the three windings corresponding to the three phases. Such a magnetic circuit corresponds to a frame forming two “Es” facing each other. The three windings are each wound on one leg of these “Es”.
However, the fans including standard three-phase self-transformers are relatively bulky. Further, the manufacturing of these self-transformers is relatively complicated, expensive and the performances are difficult to reproduce from one making to the other.
Therefore there exists a need for a compact cooling assembly including a fan provided with a device for transforming a three-phase electric current, the whole being more easily manufactured.