Product Core Brief

• Model: PW481-50
• Brand: Yokogawa
• Series: ProSafe-PLC / ProSafe-RS Power Supply Module
• Core Function: 100-120V AC input power supply for Yokogawa safety controller racks.
• Product Type: AC Power Supply Module
• Key Specs: 100-120V AC input | -20°C to 70°C operating range | Standard type, no explosion protection
• Condition: New Original / New Surplus

Key Technical Specifications

• Manufacturer: Yokogawa
• Part Number:
• Module Type: AC Power Supply Module
• System Family: ProSafe-PLC / ProSafe-RS safety system
• Input Voltage: 100-120V AC
• Suffix Code -5: Standard type with no explosion protection
• Temperature Range: -20°C to 70°C
• Output: Internal +5V / +24V DC bus for rack and I/O modules
• Status Indicators: PWR, +5V, +24V, CHECK, GND (module-dependent)
• Mounting: DIN-rail / backplane-mounted in Yokogawa safety rack
• Typical Applications: ESD racks, burner management systems, compressor protection, safety controller power feeds

Product Introduction

The PW481-50 is a Yokogawa 100-120V AC power supply module used in ProSafe-PLC and ProSafe-RS safety systems. It provides regulated internal DC bus power to the controller rack and associated I/O modules, making it a critical first component in any safety instrumented function.

Its main advantage is straightforward replacement in existing 100-120V AC cabinets without changing rack wiring or power distribution. For maintenance teams, this is a direct-fit OEM replacement part that supports existing cause-and-effect documentation, loop checks, and plant acceptance testing.

QA & Testing SOP

Power supplies are treated differently from I/O cards because a failed unit can take down an entire safety rack.

• Label and authenticity check: Verify part number, suffix code (-50), serial number, and manufacturing markings against OEM references.
• Visual inspection: Check AC terminal block, backplane connector, housing, fuses, capacitors, and PCB for heat damage, corrosion, or rework.
• AC input test: Apply 100-120V AC on a bench test rack and verify normal power-up sequence with no abnormal noise or heating.
• Output verification: Measure internal +5V and +24V DC bus rails with a Fluke-class multimeter and confirm they remain within specification under load.
• ESD-safe packing: Ship in anti-static packaging with terminal and backplane protection, plus label photos for receiving QA.

Installation Pitfalls & Guide

❗ Confirm input voltage before installation. The PW481-50 is a 100-120V AC module. Installing it on a 220-240V AC supply will damage the unit. For 220-240V AC systems, the PW482 series is typically used.

❗ Do not hot-swap without procedure. Removing or inserting a power supply can disturb the safety rack bus and cause an unintended trip. Follow plant MOC and safety system procedures.

❗ Check the suffix code. The “-5” suffix means standard type with no explosion protection. If the cabinet requires explosion-protected hardware, the -E suffix variant may be needed.

❗ Verify redundant supply configuration. Many ProSafe-RS racks use dual power supplies. Mixing incompatible models, firmware, or conditions can create uneven loading or diagnostic faults.

Replacement steps:

1. Pre-install: Confirm input voltage, suffix code, rack position, and ESD precautions.
2. Removal: Follow safety system procedures, isolate AC power if required, label wiring, and remove the module.
3. Install: Seat the module firmly, reconnect AC wiring, and verify terminal torque and grounding.
4. Power-on test: Restore AC power, check status LEDs, measure DC bus outputs, and confirm rack diagnostics are normal.

Technical FAQ

Is pricing flexible?
Yes. Price depends on condition, stock availability, label completeness, test records, and whether the unit is new original or new surplus. Urgent shutdown replacements can be prioritized.

What warranty is included?
Surplus power supply modules usually carry a limited functional warranty, often 30–90 days, unless otherwise agreed. Final terms depend on stock source and customer QA requirements.

Can this replace a PW482-50?
No. The PW481-50 is rated for 100-120V AC input, while the PW482 series is for 220-240V AC input. Substituting the wrong voltage rating can damage the module and the rack.

Is it compatible with my ProSafe-RS rack?
It is a Yokogawa ProSafe-PLC / ProSafe-RS power supply, but rack generation, slot position, redundant supply rules, and system version should be confirmed against your cabinet documentation before ordering.

Do you provide test records?
We can provide label photos, bench power-up notes, DC output measurements, and packing records. Full load-bank testing or formal test certificates can be arranged if required.