Siemens 6ES5955-3LF41 / 6ES5955-3LF44
S5 955 rack power supply for SIMATIC S5-135U, S5-155U and EU 185U systems, with selectable 120/230 V AC input and a 5 V DC, 40 A main output.
Product Overview
The Siemens 6ES5955-3LF41 and 6ES5955-3LF44 belong to the SIMATIC S5 955 power-supply family used in central and expansion racks. The unit converts the selected AC line input into the regulated voltages required by the rack and provides front-panel monitoring for supply status, fan condition, battery condition and alarm circuits.
This is a legacy SIMATIC S5 product. For maintenance procurement, the complete order number and the installed unit configuration are more important than the general description alone. Send a clear photo of the front panel and rating plate with your inquiry so the rack interface, voltage selector, fan connections and battery circuit can be checked before shipment.
Technical Data
| Manufacturer | Siemens |
| Product family | SIMATIC S5 955 power supply module |
| Order numbers covered | 6ES5955-3LF41; 6ES5955-3LF44 |
| Compatible system family | CC S5-135U / S5-155U; EU 185U |
| AC line input | Selectable 120 V AC or 230 V AC, 50/60 Hz |
| Rated input current | 4.5 A at 120 V AC; 2.6 A at 230 V AC |
| Main DC output | 5 V DC, 40 A |
| Auxiliary outputs shown on 3LF44 nameplate | 24 V DC / 2.8 A and 15 V DC / 2 A |
| Front monitoring | Voltage status, fan fault/warning, alarm and battery indication |
| Country of origin | Austria |
| Approx. measured stock-unit size | 438 × 318 × 102 mm; approx. 6.15 kg |
Lifecycle and Replacement Guidance
6ES5955-3LF44 is a closely related later S5 955, 40 A power-supply version for the same S5-135U/155U and EU 185U system family. Before substituting either version, verify all of the following:
- central or expansion rack type and rack revision;
- 120/230 V AC selector setting and site mains supply;
- front connector positions and existing wiring assignments;
- external 24 V monitor, fan warning/alarm and battery connections;
- mechanical dimensions, mounting points and cooling clearance;
- installed SIMATIC S5 documentation and machine approval requirements.
A replacement should only be approved after these checks. If the connectors, rack revision or auxiliary circuits differ, wiring changes or system engineering review may be required.
Typical Applications
- maintenance of SIMATIC S5-135U and S5-155U controller racks;
- replacement of failed rack power supplies in legacy production machinery;
- service stock for plants that have not yet migrated from SIMATIC S5;
- repair, retrofit planning and controlled shutdown maintenance;
- EU 185U expansion-rack power restoration.
Information to Include with Your RFQ
For a faster and safer quotation, provide the complete order number, front-panel photo, rating-plate photo, rack model, current input voltage, required condition, quantity and destination country. Tell us whether you need 6ES5955-3LF41 specifically or whether a verified 6ES5955-3LF44 configuration may be considered.
Frequently Asked Questions
1. What is Siemens 6ES5955-3LF41?
It is a SIMATIC S5 955 rack power-supply module for S5-135U/155U and EU 185U systems, rated for selectable 120/230 V AC input and a 5 V DC, 40 A main output.
2. Is 6ES5955-3LF41 discontinued?
Yes. Siemens lifecycle data records end of product lifecycle on 1 October 2010 and identifies the product as deleted without replacement.
3. Can 6ES5955-3LF44 directly replace 6ES5955-3LF41?
Not without verification. The rack, connectors, voltage selector, fan circuits, monitoring inputs, battery wiring and mechanical fit must be compared before a substitution is approved.
4. Which systems use this power supply?
The product family is used with SIMATIC S5-135U, S5-155U and EU 185U central or expansion rack configurations.
5. What should be checked before ordering?
Check the full order number, rack type, input voltage, connector layout, auxiliary circuits, physical condition and the exact unit shown on the rating plate.
EXPLORE MORE SIEMENS PARTS
Recommended Products
Related Siemens PLC, power-supply, I/O and drive components selected from our maintenance model list. Use the complete order number when requesting a quotation.
Need configuration confirmation?
Send your installed-unit photos and rack details with the inquiry. Our team will help compare the two order numbers before quotation.
View More Siemens Products
