General Information

Core Description

AR-PW (PW401) is a Yokogawa high-capacity power supply surge arrester featuring a plug-in main unit design. Fully compatible with standard power lines, this unit works seamlessly with industrial signal conditioners to deliver flexible instrumentation protection and stable industrial network communication.

Specific Application

• Lightning surge protection for high-load main power supply lines rated up to 100 V AC / 20 A.
• Front-end overvoltage shielding for delicate control room equipment such as signal conditioners.
• Centralized industrial plant instrumentation protection compliant with JIS C 5381-1 Class II safety profiles.

System Compatibility & Alternatives

• System Compatibility:
  Fully compatible with Yokogawa instrumentation signal conditioners, standard 30A Molded Case Circuit Breakers (MCCB), 35mm DIN rail tracks, FRK-16 multi-unit panel racks, and AR2-CK manual test checkers.
• Alternative Model & Differences:
  The alternative testing tool and component level specified for this hardware layout is the AR2-CK Arrester Checker.
• The Difference: The AR-PW (PW401) is the physical protective hardware unit consisting of a 20A rated main absorbing module and a terminal base wired directly into the live line to damp lightning spikes. The AR2-CK is a standalone diagnostic instrument used exclusively during maintenance windows to check internal degradation levels after the main AR-PW body is detached from its wired terminal base socket.

Ordering Information

Installation & Troubleshooting FAQ

Q1: What are the specific wiring and torque rules for locking down the power supply cables?

A: Use flexible twisted wire with durable round crimp-on terminals (JIS C 2805) featuring a minimum conductor cross-sectional area of 2.0 mm² (such as IV 600V vinyl or KIV electronic cables). When fastening the terminal screws, ensure the wire tightening torque does not reach or exceed 1.2 N•m to prevent damaging the internal block threads.

Q2: What should I do if the green LED status indicator on the front panel goes completely dark?

A: The green LED is the status indicator lamp for the internal surge absorbing element. It stays lit under normal power conditions and goes out entirely when the absorbing element is broken by a surge. If it goes out, the unit has sacrificed itself to protect your equipment and both the main plug-in body and the terminal block base must be replaced immediately.

Q3: Can I check or replace the main body while the power lines are actively running?

A: No, wiring and maintenance should only be done after ensuring the complete break of each external cable to prevent electrical shock. However, the mechanical design connects the main body and base via a plug-in socket. Loosening the main unit-fixing screw and pulling the body out will not open the circuit between the surge side and the protect side, keeping line continuity intact.

Q4: How should the grounding configuration be handled when installing multiple arresters side-by-side?

A: For serial installation of multiple arresters, interconnect the ground terminals of neighboring units directly to each other using a dedicated short bar. Bring the final connection path to earth ground at a single point from the last arrester in the row. Ensure the interconnect grounding wires maintain a lower effective resistance than the overall ground resistance.