6ES5 955-3LC42 Siemens SIMATIC S5 Power Supply Module
Detailed Description 6ES5 955-3LC42 is a power supply unit for Siemens SIMATIC S5 PLC series, designed to work with S5-115U controller rack. It accepts universal AC input of 115V or 230V and converts the mains power into stable 5V DC supply for the backplane bus to power CPU, signal modules and other rack components. Widely used in old chemical, metallurgy, printing and material handling automation systems equipped with SIMATIC S5 controllers.
This power supply module provides rated 5V DC output current to support full rack module configuration. It features built-in overcurrent, overvoltage and short-circuit protection. Once output overload or short circuit occurs, the PSU will shut down automatically to protect the backplane and adjacent PLC modules. LED status indicators on the front panel display power ready and fault status, helping maintenance personnel quickly judge power failure on site. The module adopts plug-in structure for direct insertion into the S5 rack, no extra wiring for backplane connection.
The unit is built with industrial-grade components and runs stably within operating temperature range of 0℃ ~ 60℃. IP20 protection grade for cabinet installation. It has power fail detection signal, which sends warning to S5 CPU before voltage drops, allowing the controller to execute data backup and safe shutdown procedures to prevent program loss. It supports hot swapping under power-off condition for convenient maintenance. The compact form fits standard S5 rack slot, saving cabinet space.
6ES5 955-3LC42 is discontinued legacy Siemens S5 spare part. Many long-running industrial plants still use SIMATIC S5 automation systems. When the original power supply fails, replacing it with identical 6ES5 955-3LC42 can reuse the existing S5 rack, CPU, I/O modules and user PLC program. No program modification or mechanical reconstruction is required. Technicians only insert the module into the rack and verify power status, so the whole PLC system resumes operation rapidly and reduces production downtime.
Before shipment, every 6ES5 955-3LC42 undergoes comprehensive functional inspection including power-on test, output voltage measurement, overload protection test and LED indicator check. All products come with 12-month warranty. Our automation technical team provides remote support for rack installation, wiring guidance and fault diagnosis. Fast global shipping is available for urgent maintenance orders.
For automation maintenance engineers and system integrators, 6ES5 955-3LC42 is reliable replacement power supply for legacy Siemens SIMATIC S5 control racks. It restores stable bus power supply for S5 PLC systems, extends service life of old automation assets and avoids high-cost whole control system upgrade.