CHAPTER 3 INSTALLATION
3.3 Noise Countermeasures
15
(2) Examples of surge absorbers
Types of Okaya Denki Sangyo Co., Ltd. surge absorbers
Surge
absorber
Type
Circuit
voltage
[Vrms]
Max. tolerable
circuit voltage
[Vrms]
Clamp
voltage
[V]
±
10%
Surge
resistance
level
8/20
µ
S [A]
Surge withstand voltage
(Electrical-discharge start
voltage)
1.2/50
µ
S [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 details characteristics, outline and connection methods
of the surge absorber.
(3) Surge absorber installation method
NC control
section
Control panel
(relay panel,
etc.)
Surge absorber (2)
Surge absorber (1)
Other device
(power supply
for panel, etc.)
Earth leakage
breaker for
panel
Input
200/
230VAC
MC
Reactor
Transformer
No-fuse
breaker
No-fuse
breaker
Circuit
protector
Grounding
Grounding plate
From power
supply
Ｂ
Ａ
NC control
section
Other device
(power supply
for panel, etc.)
Surge absorber installation method
Precautions
1) Thick wires will enhance the lighting surge absorption effect, so keep the wire as short as possible.
Wire material : Wire diameter 2mm
2
or more
Wire length : Connection length (A) to surge absorber (1) is 2m or less
For connection length (B) to surge absorber (2), and
Connection length (C) to surge absorber (3), the total wire length must be 2m or less.
2) When carrying out a withstand voltage test, while applying an overvoltage (100VAC, 1500VAC) on the power supply line,
remove surge absorbers (1) and (3) 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), (2) and (3), so the circuit protector can also be used for the other
devices.
