Schaffner's FN 5020 and FN 5030 filters are claimed to increase the
reliability of power drive systems as well as helping to eliminate most
problems related to modern frequency inverters. Based on the company's
modular 'Sinus Plus' concept, the filters can be configured according to
system requirements and application.
As a symmetrical sinusoidal output filter module, the FN 5020 converts
the PWM signal of frequency inverter outputs into a smooth sinusoidal
curve, in between the phases. Connected motors are protected against
premature ageing or even destruction, as the filter maintains dv/dt,
over-voltage stresses and motor internal magnetic losses within
acceptable limits. Acoustic motor noise is also minimised.
For tougher requirements, the FN 5030 asymmetrical sinusoidal output
filter significantly improves the voltage signal between phases and
earth. It is an add-on module, for use downstream of the FN 5020 module.
A connection to the dc-link of the frequency inverter provides a direct
return path for common mode interference currents to their origin within
the drive. Pulse-currents to earth are thus virtually eliminated, and so
both interference propagation coming from the shielded motor cable and
detrimental bearing currents are also eliminated.
Sinus Plus filters are suitable for 500Vac supply grids, with current
ratings from 25 to 120A and switching frequencies from 6kHz to 15kHz.