Siemens 6EP1436-2BA10 Industrial Power Supply – SITOP PSU300S

Siemens 6EP1436-2BA10 SITOP PSU300S 40A 24VDC 3-Phase Industrial Power Supply — Role in the Control Loop

The 6EP1436-2BA10 is a three-phase stabilized power supply belonging to Siemens’ SITOP PSU300S product family. Within a distributed control architecture, this unit occupies the critical interface between the medium-voltage AC distribution network and the 24 VDC load bus that feeds PLCs, I/O modules, field transmitters, solenoid valves, and safety relays. Its function is not merely rectification and regulation — it actively maintains bus voltage within ±1% of the 24 V nominal under dynamic load transients, ensuring that downstream logic devices never experience the brown-out conditions that cause spurious resets or data corruption in process-critical applications.

The PSU300S series was engineered for continuous-duty industrial environments where power interruption carries measurable financial and safety consequences. The 6EP1436-2BA10 specifically addresses high-current panel designs: at 40 A continuous output (960 W), it can sustain the full load bus of a mid-size automation cabinet without derating up to +60 °C ambient, and with controlled derating to +70 °C. The three-phase input topology distributes current symmetrically across all three phases, reducing harmonic injection into the facility power network and eliminating the single-phase current imbalance that degrades transformer life in large installations.

In redundant architectures, two 6EP1436-2BA10 units can be paralleled via the integrated DC OK contact and external SITOP redundancy modules, providing N+1 fault tolerance without any additional power-sharing circuitry. This makes the module a standard selection for SIL 2 and SIL 3 safety-instrumented systems where the power supply itself must not constitute a single point of failure.

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Technical Parameters

Hardware Logical Analysis

The 6EP1436-2BA10 employs a three-phase active power factor correction (PFC) front-end stage operating at a switching frequency of approximately 70 kHz. This stage maintains the input power factor above 0.99 across the full load range, which is a measurable advantage in facilities where reactive power penalties apply. The PFC stage also clamps the total harmonic distortion of input current (THDi) to below 5%, well within the limits imposed by EN 61000-3-12 for equipment connected to public low-voltage networks.

The DC-DC conversion stage uses a phase-shifted full-bridge topology with synchronous rectification on the secondary side. This topology achieves zero-voltage switching (ZVS) across the primary switches, eliminating the switching losses that dominate efficiency budgets in hard-switched designs. The result is the ≥93% efficiency figure that holds across 25–100% load range — not merely at a single operating point.

EMC performance is addressed at multiple levels. The input filter incorporates a two-stage common-mode choke and X/Y capacitor network that attenuates conducted emissions to CISPR 11 Class A limits. The enclosure uses a fully bonded steel chassis with low-impedance ground bonding points, providing a Faraday shield against radiated emissions. In environments with high-frequency interference from variable-frequency drives (VFDs) or arc welding equipment, the 6EP1436-2BA10 maintains output regulation without requiring additional external filtering.

The DC OK relay output deserves specific attention in safety-critical designs. The contact is a normally-open (NO) configuration that closes when output voltage exceeds approximately 21 V and opens within 2 ms of a voltage drop below the threshold. This response time is fast enough to trigger a PLC watchdog or safety relay before the downstream logic loses its own supply, enabling an orderly shutdown sequence rather than an uncontrolled power loss event. In redundant configurations, the DC OK contacts of both parallel units can be wired in series to a common alarm input, providing immediate notification if either unit degrades.

System Integration Benefits

The 6EP1436-2BA10 delivers the following measurable advantages when integrated into Siemens or third-party automation architectures:

• Deterministic bus voltage stability: Output regulation of ±1% under 0–100% load step ensures that PROFIBUS and PROFINET transceivers, which have tight supply voltage windows, operate within specification at all times.
• Thermal headroom for dense panel designs: The ≥93% efficiency at 960 W means only ~67 W of heat is dissipated internally, reducing the thermal load on the cabinet and extending the service life of adjacent components.
• Redundancy without external power-sharing resistors: The integrated current-sharing architecture allows direct parallel connection of two units, eliminating the voltage drop and power loss associated with external diode-OR or resistor-based sharing circuits.
• Diagnostic transparency via DC OK contact: The floating relay output integrates directly into Siemens S7-300/400/1500 digital input modules or safety relay modules, enabling power supply health monitoring within the PLC program without additional signal conditioning.
• ATEX Zone 2 certification: The unit is certified for use in potentially explosive atmospheres (gas group IIC, temperature class T4), making it suitable for oil & gas, chemical, and pharmaceutical panel installations without requiring a separate purged enclosure.
• Wide input voltage tolerance: The –15%/+10% input range (340–550 VAC) accommodates the voltage fluctuations common in industrial facilities with heavy motor loads, preventing nuisance shutdowns during motor starting transients.
• Extended temperature operation: The –25 °C lower limit supports cold-start applications in outdoor enclosures or unheated substations without requiring panel heaters in many climates.
• Compatibility with SITOP ecosystem: The 6EP1436-2BA10 is fully compatible with SITOP buffer modules (6EP1931-2DC42), redundancy modules (6EP1961-2BA21), and selectivity modules, enabling a modular, scalable power distribution architecture that can be expanded without replacing the primary supply.

Quality Assurance & Global Logistics

Every 6EP1436-2BA10 unit supplied through siemensplc.com is sourced as genuine Siemens original equipment. Each unit carries the Siemens holographic authenticity label and is traceable to its manufacturing batch via the serial number printed on the nameplate. We do not supply remanufactured, refurbished, or grey-market product. Units are stored in a climate-controlled warehouse in Xiamen, China, maintaining temperature and humidity within Siemens’ specified storage conditions to preserve component integrity prior to shipment.

Export documentation is prepared in compliance with Chinese customs regulations and the import requirements of the destination country, including commercial invoice, packing list, certificate of origin, and — where required — ATEX declaration of conformity. Shipments to Europe, North America, Southeast Asia, and the Middle East are dispatched within 1–3 business days of order confirmation via DHL Express, FedEx International Priority, or UPS Worldwide Expedited, with typical transit times of 3–7 business days to major industrial hubs.

All units are covered by a 12-month warranty from the date of shipment. Warranty claims are processed directly by our technical team in Xiamen; defective units are replaced or credited without requiring return to a Siemens service center, minimizing downtime for the end user. Pre-shipment inspection includes output voltage verification, DC OK relay function test, and visual inspection of terminal blocks and DIN rail clip integrity.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
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