
7.INSTALLATION CONDITIONS AND NOTES FANUC AC SERVO AMPLIFIER β series B-65232EN/03
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7.2 SELECTING A GROUND FAULT INTERRUPTER
To protect against electric shocks, be sure to install a ground fault
interrupter at the input section of the machine. The β series servo
amplifier drives a motor by means of the transistor-based PWM
inverter method, in which a high-frequency leakage current flows to
ground through the stray capacitance of the motor widings, power
cable and amplifier.
The ground fault interrupter or leakage-protection relay, installed on
the power supply side, can malfunction if such a leakage current
should flow. So, select an inverter-compatible ground fault interrupter
to protect against the occurrence of this malfunction. For the leakage
current of each motor, use the values indicated in the table below as a
guideline.
Motor model Commercial frequency component (mA)
βM0.2 to βM1
α1i to α8i
αM2i to αM8i
αC4i to αC8i
1.8
α12i to α22i
αM12 i
αC12i to αC22i
2.0
αC30i
2.5