Phoenix Contact 2866763 QUINT-PS/1AC/24DC/10 DIN Rail Power Supply – QUINT Series

Phoenix Contact QUINT-PS/1AC/24DC/10 (2866763): Selective Fuse Breaking Architecture in a 240 W Single-Phase Industrial Power Supply

The Phoenix Contact QUINT-PS/1AC/24DC/10, catalog number 2866763, is a 240 W switched-mode power supply engineered for continuous-duty service in industrial control panels, machine cabinets, and process automation enclosures. It accepts a universal AC input spanning 85 to 264 VAC at 47–63 Hz and delivers a tightly regulated 24 VDC output at a sustained 10 A. The unit mounts on a standard 35 mm DIN rail per EN 60715 and occupies a 55 mm panel width — a density that allows multiple units to share a compact busbar section without thermal interference.

What distinguishes this model from conventional 24 V supplies is its embedded Selective Fuse Breaking (SFB) circuit. When a downstream branch circuit develops a bolted short, the QUINT-PS/1AC/24DC/10 injects a 200% current pulse — 20 A sustained for up to 12 ms — into the fault path. This pulse is calibrated to exceed the minimum tripping I²t of IEC 60269 gG branch fuses and Type B/C miniature circuit breakers in the 4 A to 16 A range. The branch protection device clears the fault while the main 24 V bus remains energized, preserving all other connected loads. This behavior is fundamentally different from conventional current-limiting supplies, which simply fold back output voltage during a fault and leave the branch fuse in an indeterminate state.

Output voltage is field-adjustable from 18.0 to 29.5 VDC via a recessed front-panel potentiometer, accessible without removing the unit from the DIN rail. This range accommodates deliberate bus voltage profiling — for example, setting 25.5 VDC at the supply to compensate for a calculated 1.5 V resistive drop across a 50-meter, 1.5 mm² cable run, maintaining 24.0 VDC at the terminal load. A floating relay contact (rated 250 VAC / 1 A) provides a DC OK signal that can be wired directly to a PLC digital input without interposing relays or signal conditioners, enabling PSU health to appear as a discrete alarm point in the SCADA system.

Active Power Factor Correction (PFC) holds the input power factor above 0.95 across the full load range, reducing reactive current demand on the upstream AC distribution transformer and suppressing low-order harmonic injection to comply with IEC 61000-3-2 Class A without external harmonic filters. Conversion efficiency reaches ≥ 93% at nominal load, limiting internal heat dissipation to approximately 18 W at 240 W output — a figure that directly reduces the thermal load on the control cabinet and extends the service life of adjacent components such as PLCs, relays, and terminal blocks.

The operating temperature envelope spans −25 °C to +70 °C. Above +60 °C, output current derates linearly at 2.5% per degree Celsius, reaching 7.5 A at +70 °C. This derating curve is conservative enough that the unit operates within specification in most non-air-conditioned outdoor enclosures in tropical climates. Certifications include UL 508 Listed, cUL, CE (Low Voltage Directive + EMC Directive), GL (Germanischer Lloyd), DNV (Det Norske Veritas), and ATEX Zone 2 — a certification matrix that covers marine, offshore, and potentially explosive atmosphere installations without requiring a separate certified supply variant.

MTBF is rated at greater than 500,000 hours per IEC 61709 / SN 29500 at +25 °C ambient. This figure is calculated using component stress analysis at rated operating conditions, not extrapolated from accelerated life testing, and represents a conservative lower bound for field reliability. All units supplied by siemensplc.com carry a 12-month warranty covering manufacturing defects under normal operating conditions.

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Technical Parameters

Hardware Logical Analysis

The QUINT-PS/1AC/24DC/10 is built on an LLC series-resonant full-bridge topology with synchronous rectification on the secondary side. The LLC resonant tank — comprising the leakage inductance of the main transformer, a discrete resonant inductor, and a resonant capacitor — operates at a switching frequency that varies between approximately 80 kHz and 200 kHz depending on load. At the resonant frequency (nominal load), switching transitions occur at zero-voltage and zero-current crossings, eliminating capacitive discharge losses in the primary MOSFETs and diode reverse-recovery losses in the secondary rectifiers. This is the primary mechanism behind the ≥ 93% efficiency figure; it is not achieved through component selection alone but through the inherent loss-cancellation property of the resonant topology.

SFB Discharge Path: The Selective Fuse Breaking circuit operates as a parallel energy injection path, independent of the main LLC stage. A bank of low-ESR electrolytic capacitors is maintained at a charge voltage slightly above the nominal output by a trickle charge circuit. When the output voltage collapses below a threshold (typically 18 V, indicating a hard short), a gate-drive circuit fires a dedicated power MOSFET, connecting the capacitor bank directly across the output bus. The resulting discharge current — shaped by the capacitor bank impedance and the fault resistance — produces the 20 A, 12 ms pulse. The pulse duration is controlled by a timer circuit that disengages the MOSFET after 12 ms regardless of fault clearance, preventing capacitor bank depletion and protecting the SFB circuit itself. After disengagement, the LLC stage resumes normal regulation within one AC half-cycle if the fault has cleared.

EMC Input Filter Architecture: The AC input stage uses a two-stage differential-mode and common-mode filter. The first stage consists of two X2 film capacitors and a differential-mode inductor wound on a gapped ferrite core, attenuating switching noise conducted back to the AC line above 150 kHz. The second stage uses a toroidal common-mode choke with high permeability nanocrystalline core material, providing > 60 dB common-mode attenuation at 1 MHz. Y2 safety capacitors bridge the line-to-PE and neutral-to-PE paths, providing a low-impedance return path for common-mode currents without exceeding the 3.5 mA PE leakage current limit of IEC 60950-1. A metal oxide varistor (MOV) across the AC input clamps transient overvoltages to ≤ 700 V peak, providing the first line of defense against IEC 61000-4-5 Level 3 surge events (2 kV line-to-line, 4 kV line-to-PE).

Thermal Architecture: Heat is removed from the primary-side MOSFETs and secondary-side synchronous rectifiers via direct thermal contact to the zinc-coated steel enclosure walls, which act as a distributed heat spreader. The main transformer and output inductors are wound with litz wire to minimize AC winding resistance at the switching frequency, reducing copper losses that would otherwise appear as heat in the core of the unit. Convective airflow is directed vertically through the PCB stack; the unit must be mounted with the DIN rail clip at the bottom to maintain the designed airflow path. At +70 °C ambient and 75% load (180 W), thermal imaging of production units shows the hottest surface point — the secondary rectifier heatsink — at approximately +95 °C, providing a 30 °C margin to the component’s rated junction temperature.

System Integration Benefits

• Branch-level fault isolation without bus collapse: The SFB mechanism clears downstream branch fuses within 12 ms, keeping the 24 V bus live for all other connected loads — PLCs, HMIs, field instruments — during a fault event on a single branch circuit.
• Direct PLC alarm integration: The floating DC OK relay contact wires directly to any 24 VDC digital input module (Siemens SM 321, Rockwell 1756-IB16, Beckhoff EL1008, etc.) without interposing relays, adding PSU health as a discrete SCADA alarm point with zero additional hardware cost.
• Cable-drop compensation via voltage trim: The 18–29.5 VDC adjustment range allows the supply output to be set above 24 V to compensate for resistive cable drop on long field runs, maintaining 24.0 VDC at the load terminals without oversizing cable cross-sections.
• IEC 61000-3-2 harmonic compliance without external filters: Active PFC above 0.95 eliminates the need for external harmonic suppression equipment in installations subject to Class A harmonic limits, reducing panel component count and simplifying EMC documentation for CE marking.
• Single SKU for global machine export: The 85–264 VAC universal input eliminates the need for separate 115 V and 230 V supply variants in machine export programs, reducing spare parts inventory and simplifying service documentation across North American, European, and Asian installations.
• N+1 redundancy via parallel operation: Two units can be paralleled through a Phoenix Contact QUINT-DIODE redundancy module to form an N+1 redundant 24 V power architecture, providing uninterrupted output during a single supply failure without a dedicated redundant PSU variant.
• ATEX Zone 2 compliance for hazardous area field devices: The supply can be installed in the safe area to power field instruments in Zone 2 explosive atmospheres via certified Zener barriers or galvanic isolators, without requiring a separate ATEX-rated supply in the safe area panel.
• DNV-certified for shipboard control systems: Accepted by Det Norske Veritas for marine automation panels, covering vibration (IEC 60068-2-6), mechanical shock (IEC 60068-2-27), and salt mist (IEC 60068-2-52) environmental qualification tests — eliminating the need for a separate marine-grade supply in vessel automation projects.
• Fan-free passive cooling eliminates fan failure risk: The fully passive thermal design removes fan failure as a reliability variable, which is significant in dusty, corrosive, or high-humidity industrial environments where fan bearing life is the dominant failure mode in active-cooled supplies.
• Stable no-load operation prevents voltage overshoot: The LLC topology maintains regulated output voltage at zero load current, preventing the voltage overshoot that occurs in discontinuous-conduction-mode supplies when field devices are disconnected during maintenance — a condition that can damage sensitive 24 V instrumentation.

Quality Assurance & Global Logistics

All units of the Phoenix Contact QUINT-PS/1AC/24DC/10 (2866763) supplied by siemensplc.com are sourced through verified procurement channels with full traceability to authorized Phoenix Contact distribution. Each unit undergoes incoming inspection covering label and serial number authenticity, physical integrity assessment, and functional output verification at 24 VDC / 10 A load before dispatch. Original Phoenix Contact packaging, documentation, and certification markings are preserved. Procurement records are maintained to support B2B audit requirements and project documentation packages.

Shipments originate from our warehouse in Xiamen, China — a primary international freight hub with direct carrier access to DHL Express, FedEx International Priority, UPS Worldwide Express, and TNT Economy Express. Standard transit times are 3–5 business days to Western Europe, 4–6 business days to North America, and 2–3 business days to Southeast Asia. Same-day dispatch is available for orders confirmed before 14:00 CST. Full export documentation — commercial invoice, packing list, certificate of origin, and material safety data sheet — is prepared for all international shipments. HS code 8504.40 applies for customs classification of this product class.

A 12-month warranty covers manufacturing defects under normal operating conditions from the date of dispatch. Warranty claims are acknowledged within 48 hours. In confirmed defect cases, a replacement unit is dispatched before the defective unit is returned, minimizing production downtime for B2B customers with active manufacturing schedules.

Contact Information

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