2 Compatible Devices
2.3.1 Molded-case Circuit Breakers, Ground Fault Detectors, and Magnetic Contactors
2-20
2.3
Peripheral Devices
2.3.1
Molded-case Circuit Breakers, Ground Fault Detectors, and Magnetic
Contactors
Always install a circuit breaker to protect the main circuits. The type of circuit breaker that is required depends
on what you need to detect.
Detecting only overcurrent: Use a molded-case circuit breaker.
Detecting overcurrent and leakage current: Use a ground fault detector that detects overloads and leakage cur-
rent. Or, use a molded-case circuit breaker together with a ground
fault detector that detects only leakage current.
(1) Molded-case Circuit Breaker
A molded-case circuit breaker shuts OFF the power supply when it detects an overcurrent. Install a molded-
case circuit breaker between the power supply and the main circuit power supply input terminals (R/L1, S/L2,
and T/L3).
Select the molded-case circuit breaker based on the information in
(4) Converter Input Current and Inrush
Current
.
(2) Ground Fault Detector
A ground fault detector detects leakage current. Some models will also detect overcurrent in addition to leak-
age current. Use the type that is suitable for your application. Install a ground fault detector between the power
supply and the main circuit power supply input terminals (R/L1, S/L2, and T/L3).
Recommended ground fault detector: A ground fault detector with harmonic countermeasures and a rated
sensed current of 30 mA or higher for each power regeneration con-
verter. A ground fault detector with harmonic countermeasures removes
leakage current for harmonics and detects only leakage current in the
frequency range that presents a hazard to humans. If you use a ground
fault breaker that does not have harmonic countermeasures, the leakage
current from the harmonics will increase the chance of malfunctions.
Select the ground fault detector based on the information in
(4) Converter Input Current and Inrush Current
.
(3) Magnetic Contactors
The magnetic contactor for the control circuit power supply turns the control circuit power supply ON and
OFF. The magnetic contactor for the main circuit power supply turns the main circuit power supply ON and
OFF. Use a magnetic contactor (MC) to turn OFF the control power supply or main circuit power supply
sequence.
Note: If the magnetic contactor on the main circuit power supply input is turned ON and OFF frequently, the
Σ
-V-SD servo
driver may be damaged. Do not turn the power supply ON and OFF with the magnetic contactor more than one time
every 30 minutes.
Select the magnetic contactor based on the information in
(4) Converter Input Current and Inrush Current
.
WARNING
• Always install a molded-case circuit breaker or ground fault detector in the main circuit.
Failure to observe this warning may result in electric shock, equipment damage, or fire.