Buying used Siemens SITOP power supplies and UPS modules

Keep the full 6EP article and product revision

Record the nameplate, including every suffix, input range, output rating and product state or revision. Identify the component’s role: AC/DC power supply, load supply, UPS basic unit, storage expansion, battery assembly, selectivity module or redundancy module.

For 6EP3436-8SB00-0AY0, the manufacturer documents a 24–28.8 V adjustment range for PR1 and 24–28 V from PR2. Ask for the actual revision when a machine uses an adjusted output. Product-family names and similar housings do not establish identical electrical limits.

SIMATIC PM70 W and PM190 W supply field circuits, sensors and actuators at 24 V DC, with 3 A and 8 A rated current respectively. Check the load supply separately from the PLC system’s other power requirements.

6EP1336-3BA00 vs 6EP1336-3BA10: check the input

These two 20 A models have different input arrangements. Record whether the installation uses single-phase AC, phase-to-phase AC or DC, and compare the documented operating range and selection method.

The published ranges describe permitted conditions and still need the manufacturer’s startup and derating checks. On 6EP1336-3BA10, input below 100 V has a separate temperature condition at 50 °C. Include the minimum expected input voltage and cabinet temperature in the enquiry.

Separate continuous current from Extra Power

Add the continuous demand of the connected loads and identify startup peaks and their repetition rate. Use the output-current rating at the actual input voltage, output setting and ambient temperature. Raising an adjustable output can reduce the permitted current under the same power limit.

6EP1333-1LB00 supplies 5 A up to 45 °C and 3.5 A at 60 °C. 6EP1333-2BA20 separately lists 6 A in the −10…45 °C range and 7.5 A Extra Power for 5 seconds per minute. The 7.5 A figure cannot be used as a continuous rating.

For 6EP1336-3BA10, the nominal output is 20 A with a 480 W limit, and Extra Power is 30 A for 5 seconds per minute. Share the load profile when requesting a test so that the agreed evidence matches the application.

Match the UPS basic unit and energy-storage component

6EP1933-2EC51 UPS500S is a 24 V DC, 15 A basic unit with nominal 5 kWs capacitor storage. The unit kWs measures energy. The manual lists a typical 9 seconds of buffering at 15 A for the fully charged basic unit, or 20 seconds with one compatible expansion.

6EP1935-5PG01 UPS501S is a 5 kWs expansion module fed from the basic unit. Confirm the basic-unit model, number of expansions and connection components. The timer’s 5–315 second setting range does not guarantee that stored energy will sustain the load for the selected time.

6EP1935-6ME21 is a separate AGM battery assembly with two nominal 12 V, 7 Ah batteries. Match its UPS and fuse arrangement. Request battery date codes or capacitor charge/discharge evidence and a test at the intended load; nominal energy and capacity do not establish remaining life or actual runtime.

Compare branch protection and redundant supply paths

The following selectivity modules each protect four 24 V DC branches. Compare the adjustable threshold per branch and the signal sent to the controller. Check product version for shutdown and reset behavior.

The 12 A or 40 A input rating covers the combined supply. Do not parallel the outputs of these selectivity modules. The older 6EP1961-2BA00 also has a documented restriction against operation with 40 A DC-UPS modules 6EP1931-2FC21 and -2FC42.

Redundancy modules serve a different function by decoupling source supplies. 6EP1961-3BA21 has a documented 0–40 A output range and 6EP1964-2BA00 has 0–10 A. A redundancy arrangement must also let the remaining source carry the required load after one supply fails. Include both power-supply models, voltage-drop allowance and the required failure-state test.

Prepare a complete power-supply replacement enquiry

• Complete article and revision, readable nameplate photos and the component’s role in the cabinet.
• Input voltage and phase arrangement, required output, continuous load, startup peaks and cabinet temperature.
• Connected UPS, storage, selectivity or redundancy modules, with their full models and the relevant wiring.
• Acceptable condition, supplied terminals and accessories, actual-unit photos and required load, channel or discharge test evidence.
• Quantity, destination and required date, followed by written confirmation of price and dispatch timing.

Review our existing condition definitions, warranty / DOA terms, returns policy and shipping and payment information alongside the quote.

Manufacturer references and reviewed product families

These selection examples use Siemens documentation. Each linked product records the relevant source and rating conditions, including additional battery, three-phase and redundancy references. Compare the documents for the actual offered revision and installed configuration.

• SITOP PSU100L, August 2016, pages 33–35
• SITOP modular 1ph/2ph, April 2025, pages 4 and 37–40
• SITOP PSU8200 1ph, August 2016, pages 44–47
• SITOP UPS500S / UPS501S, October 2015, pages 5–7
• SITOP selectivity modules, April 2019, pages 49–56

• SITOP PS207, Smart and Lite

For controller and rack purchasing requirements, read the used PLC parts buying guide.