Drive output filter improves efficiency

Schaffner has introduced a new high-performance range of sinusoidal output filters for frequency inverters.

Schaffner has introduced a new high-performance range of sinusoidal output filters for frequency inverters.

The range offers a cost-effective solution for many problems related to modern motor drive systems.

The FN 5010 output filter significantly restricts the excessive dv/dt and overvoltage stress on the motor windings caused by the inverter's PWM signal.

This effectively increases the service life of the motor by reducing the likelihood of failure, and the significant down-time costs associated with maintenance or replacement.

In addition, the output filters convert the pulsewidth-modulated output signal into a smooth sinewave with a low harmonic content, which offers many advantages.

First, the system efficiency is improved by reducing eddy current losses and displacement currents in the motor.

Secondly, leakage currents through the motor bearings to earth will be eliminated by the filter and the bearing's service life increased.

Thirdly, acoustic noise is also reduced, an important consideration in applications such as air-conditioning and ventilation systems, where air ducts can amplify the noise and distribute it to the whole building.

Furthermore, lower pulse currents coupled with the shielded motor cables to earth result in lower semiconductor losses in the inverter and also produce a better overall EMC environment.

Typical applications will be found wherever a motor needs to run at different speeds and therefore is controlled by a motor drive; from pumps and conveyors, to lifts and cranes, machine tools, alternative energy supply systems, robotics, medical, chemical and general industrial automation.

The filters are designed to operate in common 400V AC supply grids and with current ratings from 2.5 to 610A, in small incremental steps.

They allow switching frequencies from 4 to 16kHz and motor frequencies up to 60Hz.

A 690V AC version is also being developed.

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