Mitsubishi Electronics MDS-D-SPJ3 Manuel D’Utilisation

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When installing an earth leakage breaker, select the breaker on the following basis to prevent the breaker from 

malfunctioning by the higher frequency earth leakage current generated in the servo or spindle drive unit.

Obtaining the earth leakage current for all drive units referring to the following table, select an earth leakage 

breaker within the "rated non-operation sensitivity current".

Usually use an earth leakage breaker for inverter products that function at a leakage current within the 

commercial frequency range (50 to 60Hz).

If a product sensitive to higher frequencies is used, the breaker could malfunction at a level less than the 

maximum earth leakage current value.

(Note)

Maximum earth leakage current: Value that considers wiring length and grounding, 

etc.(Commercial frequency 50/60Hz)

When actually measuring the earth leakage current, use a product that is not easily affected by the higher 

frequency earth leakage current. The measurement range should be 50 to 60Hz.

6mA

15mA

1mA

2mA

1. The earth leakage current tends to increase as the motor capacity increases.

2. A higher frequency earth leakage current will always be generated because the inverter circuit in 

the drive unit switches the transistor at high speed. Always ground to reduce the higher frequency 

earth leakage current as much as possible.

3. An earth leakage current containing higher frequency may reach approx. several hundreds of mA. 

According to IEC479-2, this level is not hazardous to the human body.