Overview
The Crydom 6401A is a solid-state relay output module designed for industrial PLC and machinery control applications. This module converts low-voltage DC logic signals (3.0–6.0VDC) into switched 120VAC loads, supporting continuous output currents up to 3.0 amperes. Although discontinued by the manufacturer, the 6401A remains a trusted component in maintenance and retrofit scenarios across legacy automation platforms.
Key Features
- 3.0A output current rating at 120VAC
- 3.0–6.0VDC logic input range for broad compatibility
- Solid-state design—no moving contacts, long operational life
- 4-pin DIN footprint with hold-down screw for secure mounting
- Thru-hole package suitable for direct PCB integration
Technical Specifications
- Output Voltage: 120VAC
- Output Current (Max): 3.0A
- Input Voltage (Logic): 3.0–6.0VDC
- Pin Configuration: 4-pin
- Mounting: Thru-hole with hold-down screw
- Package Type: I/O Module Relay
- Operating Status: Discontinued by Manufacturer
- Weight: 0.09 lbs (approx.)
- RoHS Compliance: Yes
Typical Applications
The Crydom 6401A is commonly used in:
- PLC discrete output modules and I/O systems
- Industrial machinery control and automation
- Legacy control panel rebuilds and upgrades
- Equipment replacement where OEM parts are no longer stocked
- Low-current AC load switching in harsh industrial environments
Compatibility & Replacements
Compatible With
- Vintage PLC systems requiring discrete AC output relays
- Industrial control cabinets with thru-hole relay mounting
- Legacy automation platforms using 3–6VDC logic signals
- Systems requiring 120VAC switching at 3.0A or less
Replaces / Drop-In Replacement For
The Crydom 6401A directly replaces other 6401A units. Verify compatibility with your system integrator before ordering to ensure correct pinout and voltage specifications match your application.
Works With
- Crydom solid-state relay product families
- Allen-Bradley legacy I/O modules (verify configuration)
- Siemens S5 and older PLC discrete output cards
- Standard industrial 120VAC control circuits
- Logic-level DC control signals (3–6V)
