PW501

The Yokogawa PW501 is a power supply module identified for use in Yokogawa industrial control equipment. It is intended to provide electrical power to the associated system hardware. Before selecting it as a replacement, the complete equipment configuration, power supply specifications, and applicable hardware revision should be checked against the installed system.

Function and System Role

The PW501 is designed for Yokogawa communication equipment, including the YNT511D optical bus repeater and YNT512D bus repeater. It accepts 100-120 V AC input and converts it into insulated DC power supplies, which are distributed to the repeater component units through the internal backboard.

This power distribution arrangement allows the repeater's internal communication components to receive their required operating power from a dedicated supply module.

Electrical Input and Protection

The PW501 uses a dedicated AC input connection with L and N terminals and a separate grounding terminal. The module also incorporates a power ON/OFF switch, a power indicator lamp, and a replaceable tubular fuse.

The documented fuse specification is 250 V, 1 A. The corresponding Yokogawa replacement fuse is A1361EF. The power indicator illuminates green when the input is energized and the module switch is ON.

Technical Specifications

Parameter	Specification
Model	PW501
Brand	Yokogawa
Product Type	Power Supply Module
Input Voltage	100-120 V AC
Fuse Rating	250 V, 1 A
Fuse Part Number	A1361EF
Power Distribution	Insulated DC power via internal backboard
Power Connection	L and N terminals
Grounding	Dedicated grounding terminal
Power Control	ON/OFF switch
Status Indication	Green POWER lamp
Mounting	Nest-mounted, backboard connection

Installation and Maintenance Considerations

The PW501 is installed in the repeater nest and connects to the internal backboard. Its replacement requires attention to both the external AC wiring and the backboard connector.

Yokogawa specifies the following replacement precautions:

• Turn off the module power switch and external power source before removal.
• Disconnect the power cables and grounding cable.
• Release the four mounting screws and withdraw the module using its handle.
• Insert the replacement module along the nest guide rail and secure it.
• Reconnect the power and grounding cables, restore the external supply, and verify that the POWER lamp illuminates.

The manufacturer documents an 8-year recommended replacement period for the PW501 under an average ambient temperature of 40 deg C or lower. This is a preventive maintenance guideline rather than a guaranteed service life.

Frequently Asked Questions

Q: What is the difference between PW501, PW502, and PW504?

A: These models are distinguished by their input power requirements:

• PW501: 100-120 V AC
• PW502: 220-240 V AC
• PW504: 24 V DC

The input voltage must match the available power source and the installed repeater configuration.

Q: Which replacement fuse is specified for the PW501?

A: Yokogawa specifies fuse part number A1361EF, rated at 250 V and 1 A. Turn off the module and external power source before replacing the fuse.

Q: Can the PW501 be replaced while the equipment is energized?

A: The documented replacement procedure requires switching off the module and external power source before removal. Live replacement should therefore not be assumed or performed based on a hot-swap capability claim.

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