Nanocrystalline soft magnetic materials are now superior to permalloys, ferrites and even amorphous cobalt based alloys in a growing range of applications. The table below identifies different properties of the various soft magnetic materials that are available today.
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see our CoolBLUE Inductive Absorbers website.
Cool Blue for Inverter Drive Motor Systems
Common Mode Choke Design Guide for Reducing Motor Bearing Currents
A primary application is common mode chokes specifically designed to reduce EMI voltage spikes in Inverter Drive Motor Systems.
Cool Blue® toroids made from the nanocrystalline material NANOPERM are being used increasingly to reduce damaging motor bearing currents in modern high power inverter systems operating at high switching frequencies. As a result of these unwanted currents, the bearings corrugate, leading to electrical breakdown in the lubrication and finally to a standstill of the entire motor.
The use of Cool Blue® cores not only significantly reduces the over voltage peaks at the motor terminals, but also suppresses the asymmetrical EMI currents which are generated by the parasitic currents of the motor itself together with the motor cable. In order to achieve an efficient reduction in these destructive effects, one or more Cool Blue® of suitable geometry have to be placed together over the connector cables in the DC-link as well as at the inverter output. In this configuration, the cores operate as a common-mode choke.
This method significantly increases the service life of the motor bearings and thus reduces maintenance costs and standstill periods.