Instruction manual

Appendix 7. EMC Installation Guidelines
A7 - 16
(2) Example of surge protector installation
An example of installing the surge protector in the machine control panel is shown below.
A short-circuit fault will occur in the surge protector if a surge exceeding the tolerance is applied.
Thus, install a circuit protection breaker in the stage before the surge protector. Note that almost no
current flows to the surge protector during normal use, so a breaker installed as the circuit
protection for another device can be used for the surge protector.
Installing the surge absorber
CAUTION
1. The wires from the surge protector should be connected without extensions.
2. If the surge protector cannot be installed just with the enclosed wires, keep
the wiring length of A and B to 2m or less. If the wires are long, the surge
protector's performance may drop and inhibit protection of the devices in the
panel.
3. The selected surge protector differs according to the input power voltage.
NC unit
Control panel
(relay panel,
etc.)
(1) Surge protector
(Protection across phases)
Other device
(panel power
su
pp
l
y,
etc.
)
Panel earth
leakage
breaker
Input
power
supply
Breaker
AC reactor
Transformer
Grounding
Grounding plate
Factory
power
B
A
MC
Contactor
Breaker
Breaker
Power supply
unit and
drive unit
Other device
(panel power
su
pp
l
y,
etc.
)
(2) Surge protector
(Protection across each phase's grounding)