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3. INSTALLATION
3.4 Noise Countermeasures
I - 16
(2) Examples of surge absorbers
Types of Okaya Electric surge absorbers
Surge
absorber
Type
Circuit
voltage
[Vrms]
Max. tolerable
circuit voltage
[Vrms]
Clamp
voltage
[V] ±10%
Surge
resistance
level
8/20µs [A]
Surge withstand voltage
(Electrical-discharge
start voltage)
1.2/50µs [V]
(1) RAV-781BWZ-4 250 500 700 2500 2k
(2) RAV-781BYZ-2 250 300 783 2500 20k
(3) RAV-781BXZ-4 250 500 700 2500 2k
*
Refer to the manufacturer's catalog for detailed characteristics, outline and connection methods of the surge
absorber.
(3) Surge absorber installation method
Surge absorber installation method
Control panel
(Relay panel,
etc.)
Surge absorber (2)
Surge absorber (1)
Earth
leakage
breaker
for panel
Input
200V/
230VAC
No-fuse
breaker
No-fuse
breaker
MC
Reactor
Transformer
Circuit
protector
Grounding
Grounding
From power
supply
C
B
A
NC drive
section
Other devices
(power supply
for panel,
etc.)
Other devices
(power supply
for panel, etc.)
NC control
section
Precautions
1) Thick wiring enhances the lightning surge absorbing effect, so make the wiring as thick and short as
possible.
Wire material : Wire diameter 2mm
2
or more
Wire length : Connection to surge absorber (1): Wire length (A) is 2m or less
Connection to surge absorber (2): Wire length (B) is 2m or less
Grounding to surge absorber (2) : Wire length (C) is 2m or less
2) When carrying out a dielectric voltage-withstand test on the power supply line, remove surge absorber
(2) as the surge absorber will function with the applied voltage.
3) A short-circuit accident will occur if a surge exceeding the tolerance is applied on the surge absorber.
Thus, always insert a circuit protector to protect the power supply line.
The current does not flow constantly to surge absorbers (1) and (2), so the circuit protector can also be
used for the other devices.