In single phase applications the earth leakage current is present all of the time. For three phase applications under normal conditions with the three phases balanced, earth leakage currents are extremely small - the max values stated are worst possible values such as would occur momentarily during switch on or failure of one or two phases.

Design and Test Criteria

Generally with motor drive systems, the emission levels are greatly affected by the length of the cable between the drive itself and the motor - longer cables will cause considerably higher emissions.
The inverter / filter combinations here have been designed and tested to achieve compliance to:-

EN 55022:1994, Class B for use in domestic / light industrial environments (Equivalent to the RF emissions tests of Power Drive Standard

EN 61800-3:1996 for drives with <25A input current) when fitted with up to 25m motor output cable and to:

EN 55011:1991 Group 1, Class A for use in industrial environments (Equivalent to the RF emissions tests of Power Drive Standard

EN 61800-3:1996 for drives with >25A input current) when fitted with up to 50m motor output cable.