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AC-AC converters could shrink the size of drives

01 March, 2000

AC-AC converters could shrink the size of drives

Engineers working for ABB in Finland have rethought the way fans are built and have come up with new design which they say is twice as efficient as conventional designs, and is also quieter and smaller.

Instead of a conventional motor drive, the tip-driven integral fan (TDIF) uses a motor built into the ends of the impeller blades. Conventional fan drives suffer from several drawbacks. If the motor is placed in the airflow, pressure is lost, but if it placed next to the fan, it takes up valuable space. Also the gears and belts linking the motor to the fan introduce losses and can fail.

The new fan, in effect, combines the rotor and impeller in a single component. The outer rim of the fan incorporates magnets that interact with stator windings at the four corners of the fan frame to drive it. The ABB researchers say that the TDIF produces the same output as a radial fan twice the size. It also saves energy because it uses an "intelligent" speed control that cuts its speed when there is less demand for cooling.

The fan is still in development but is likely to be marketed by ABB`s Flakt operation in about two years` time. ABB says that prices will be "competitive". The ABB researchers are tight-lipped about other potential applications for the tip-drive technology but pumps and motors are possibilities.