Protect Drive Wiring; (Elcb); Installing A Ground Fault Circuit Interrupter - YASKAWA GA700 Technical Manual

2.18 Protect Drive Wiring

2.18

Protect Drive Wiring

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Installing a Molded-Case Circuit Breaker (MCCB) or Earth Leakage Circuit
Breaker (ELCB)
Install a molded-case circuit breaker (MCCB) or an earth leakage circuit breaker (ELCB) for line protection
between the power supply and the main circuit power supply input terminals R/L1, S/L2, and T/L3. This protects
the main circuit and devices wired to the main circuit while also providing overload protection.
The following describes the selection criteria for an MCCB or ELCB, and the precautions that should be followed
when connecting the device.
• The capacity of the MCCB or ELCB should be 1.5 to 2 times the rated output current of the drive. Use an
MCCB or ELCB to keep the drive from faulting out instead of using overheat protection (150% for one minute
at the rated output current).
• If several drives are connected to one MCCB or ELCB that is shared with other equipment, use a sequence that
shuts the power OFF when errors are output by using magnetic contactor (MC) as shown in the following
figure.
A - Power supply
WARNING! Electrical Shock Hazard. Disconnect the MCCB (or ELCB) and MC before wiring terminals. Failure to comply may
result in serious injury or death.
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Installing a Ground Fault Circuit Interrupter

High frequency leakage current is generated because the drive's output performs high-speed switching. To prevent
electric shock accidents or earth leakage fires induced by ground fault protection, install an earth leakage circuit
breaker (ELCB).
The breaker used at the power input side of the drive should be designed specifically for high frequencies, and
each drive should have a cumulative sensitivity amperage of at least 30 mA. Through the use of a specialized
breaker, high-frequency leakage current is eliminated, and only the leakage current from frequency bands harmful
to humans is detected.
A device without a countermeasure against high frequencies can malfunction due to high frequency leakage
current. If a malfunction occurs using a device without a countermeasure, lower the carrier frequency of the drive,
switch to a more capable breaker, or use an earth leakage circuit breaker having a cumulative sensitivity amperage
of at least 200 mA for each drive.
The following factors can have an effect on leakage current:
• Drive capacity
• Carrier Frequency
• Wiring distance and types of motor cables
• EMI/RFI filter
To protect personnel and drives, select earth leakage circuit breakers that can handle both AC and DC power
supplies, and which are designed specifically to be able to deal with high frequencies.
Note:
Yaskawa recommends the use of the following earth leakage circuit breakers, which were designed to be used with high frequencies.
• Mitsubishi Electric Corporation; NV series
• Schneider Electric; NS series
88
Figure 2.65 Connecting a Molded-Case Circuit Breaker
YASKAWA ELECTRIC SIEP C710617 01B YASKAWA AC Drive GA700 Technical Manual
B - Drive