Nanocrystalline common mode chokes for line filters

August 14, 2014 // By Graham Prophet
Common mode chokes are used as in-line filters to reduce broadband mains-borne radio interference. Wurth Electronics has developed current-compensated common mode chokes with nanocrystalline cores for this purpose.

The WE-CMBNC product family is made with nanocrystalline cores and delivers broadband attenuation. Compared with conventional cores made of MnZn and NiZn core materials, nanocrystalline cores have 20 times greater permeability. Mains borne interference can be reduced down into the low kHz frequency range, where conventional NiZn and MnZn cores have very little attenuation.

Even in high frequency ranges, high levels of attenuation can be achieved due to the low winding capacitance. Compared with conventional cores, the Currie temperature is about three times higher, so push-pull interference cannot result in saturation of the mains choke.

Wurth Electronics Midcom/Wurth Elektronik;