Siemens 6EP1333-2AA01 Industrial Power Supply – Sitop Smart

Siemens 6EP1333-2AA01 Sitop Smart 24 VDC / 5 A Power Supply — Stabilized DC Output for Industrial Control Loops

The Siemens 6EP1333-2AA01 is a single-phase, switch-mode power supply from the Sitop Smart product family, rated at 24 VDC nominal output and 5 A continuous current, delivering 120 W of stabilized DC power to field devices, PLC I/O rails, and distributed automation nodes. Its role in a control loop is not passive: the quality of the DC bus it maintains directly determines the noise floor seen by analog input modules, the hold-up margin available during AC line dips, and the fault-response time of downstream protection circuits. This unit is engineered to sustain a regulated 24 VDC bus under dynamic load transients typical of solenoid valve switching, motor starter coil energization, and high-density digital output toggling — conditions that expose weaknesses in lower-grade supplies through output voltage droop and ripple injection.

Sourced directly from verified Siemens distribution channels and held in stock at our Xiamen, China facility, the 6EP1333-2AA01 ships globally via DHL Express, FedEx International Priority, and UPS Worldwide, with same-day dispatch available for orders confirmed before 15:00 CST.

Real-time Stock & RFQ: [email protected] | WhatsApp: +86 18359268345

Technical Parameters

Hardware Logical Analysis

The 6EP1333-2AA01 employs a flyback converter topology with synchronous rectification on the secondary side. The primary switching stage operates at a fixed frequency of approximately 65 kHz, which places the fundamental switching harmonic well above the 50/60 Hz power line frequency and below the lower boundary of the AM broadcast band — a deliberate choice that simplifies conducted EMI filter design while keeping transformer core losses within acceptable bounds for the selected ferrite material.

EMC Architecture: The input stage incorporates a two-stage common-mode choke in series with a differential-mode capacitor network (X-capacitors) and Y-capacitors referenced to the protective earth conductor. This arrangement attenuates both differential-mode noise (generated by the switching transistor’s dV/dt transitions) and common-mode noise (coupled through the transformer interwinding capacitance). The result is a conducted emission profile that meets EN 55011 Class B limits without external filtering — a meaningful advantage in dense panel layouts where additional filter modules consume DIN rail space and introduce additional failure points.

Output Regulation and Transient Response: The secondary-side control loop uses an optocoupler-isolated feedback path to a PWM controller IC on the primary side. This galvanic isolation maintains the regulatory loop integrity while preserving the 3 kVAC reinforced isolation barrier between input and output. Under a 50% step load change (2.5 A to 5 A), the output voltage deviation is held within ±3% of nominal, recovering to within ±1% in under 2 ms — a transient performance figure that prevents false triggering of undervoltage lockout circuits in connected SIMATIC CPU modules.

Thermal Management: The unit uses a natural convection cooling strategy with an internal aluminum heat spreader bonded to the primary switching transistor and output rectifier diodes. No forced-air fan is present, eliminating the single highest-failure-rate mechanical component in power electronics. The thermal derating curve begins at 60 °C ambient: at 70 °C, the maximum continuous output current is reduced to approximately 3.75 A (75% of rated), which must be accounted for in panel thermal calculations in high-ambient installations such as outdoor enclosures or foundry environments.

Protection Logic Sequencing: Overload detection is implemented via a current-sense resistor in the output return path. When output current exceeds 105–115% of rated, the controller enters constant-current limiting mode, clamping output current while allowing voltage to droop. If the overload persists beyond approximately 3 seconds, the controller transitions to hiccup mode — cycling the output off for ~1 second and attempting restart — preventing thermal runaway in the switching transistors while providing a visible diagnostic signal (output voltage oscillation) that can be detected by a connected PLC analog input or a panel-mounted voltmeter.

System Integration Benefits

• Deterministic 24 VDC Bus Stability: Output voltage regulation of ±1% under steady-state load variations from 10% to 100% ensures that SIMATIC S7-300/400 CPU modules and their associated I/O backplanes receive a supply voltage that remains within the 20.4–28.8 VDC tolerance window specified in the S7-300 hardware manual, preventing spurious CPU STOP transitions caused by supply undervoltage.
• Low Ripple for Analog Signal Integrity: The ≤ 150 mV peak-to-peak output ripple specification is critical for 4–20 mA analog input modules. A higher-ripple supply injects noise into the analog reference rail, degrading effective resolution. At 150 mV ripple on a 24 VDC rail feeding a 12-bit analog module with a 10 V input range, the theoretical noise contribution is below 0.6 LSB — within acceptable limits for most process control applications.
• 20 ms Hold-up Time for Ride-Through: The ≥ 20 ms hold-up time at full load covers the duration of a single AC half-cycle dropout (8.3 ms at 60 Hz, 10 ms at 50 Hz) plus the response time of a typical upstream UPS or automatic transfer switch. This prevents nuisance PLC restarts during momentary grid disturbances without requiring a separate buffer module.
• Wide-Range AC Input for Global Deployment: Auto-switching between 93–132 VAC and 187–264 VAC input ranges eliminates the need for manual voltage selection jumpers, reducing commissioning errors in international projects where panel builders may not verify local grid voltage before energization.
• DIN Rail Form Factor for Panel Density: The 55 mm width occupies 3.5 DIN rail modules (based on 17.5 mm module pitch), allowing a standard 600 mm wide panel section to accommodate up to 10 units in a single row — a density figure relevant for machine builders standardizing on a single PSU model across multiple control cabinet sizes.
• IP20 Enclosure for Open-Frame Panel Use: IP20 protection is appropriate for installation inside sealed or ventilated control enclosures (IP54 or higher) where the PSU is not directly exposed to particulate contamination or liquid ingress. This is the standard protection class for DIN rail components in IEC 61439-compliant switchgear assemblies.
• Certified for Marine and Hazardous Area Applications: GL (Germanischer Lloyd) certification enables use in marine automation panels aboard vessels subject to classification society inspection. ATEX Zone 2 compatibility (when installed in a certified enclosure) extends the application envelope to petrochemical and gas processing facilities where explosive atmospheres may be present.
• Passive Cooling Eliminates Fan Maintenance: In applications with 8,760 annual operating hours (continuous process plants), a fan-cooled PSU with a 50,000-hour fan MTBF requires planned replacement every 5.7 years. The fanless 6EP1333-2AA01 removes this maintenance interval entirely, reducing lifecycle maintenance cost and unplanned downtime risk in remote or difficult-to-access installations.

Quality Assurance & Global Logistics

Every 6EP1333-2AA01 unit stocked at our Xiamen facility is sourced exclusively through verified Siemens authorized distribution channels. Upon receipt, each unit undergoes a structured incoming inspection protocol: factory label authentication (including holographic security features), original packaging integrity check, and a powered functional test confirming output voltage regulation and protection circuit operation. Serial numbers are cross-referenced against Siemens’ product traceability database where applicable.

Units are stored in a temperature-controlled warehouse (18–25 °C, 40–60% RH) in original Siemens factory packaging to preserve electrostatic discharge (ESD) protection and prevent moisture ingress into terminal blocks and PCB assemblies. Anti-static packaging is used for all outbound shipments.

Xiamen’s geographic position — adjacent to Xiamen Gaoqi International Airport and within 48 hours of major Asia-Pacific logistics hubs — enables next-flight-out dispatch for urgent orders. Standard export documentation (commercial invoice, packing list, certificate of origin) is prepared same-day. A certificate of conformity and 12-month warranty certificate are included with every shipment. For project orders requiring batch traceability records or third-party inspection (SGS, BV, TÜV), these can be arranged with 2–3 business days’ notice.

Shipping options: DHL Express (2–4 business days to Europe/North America), FedEx International Priority (2–3 business days), UPS Worldwide Express, and sea freight consolidation for bulk orders exceeding 50 units. All shipments are fully insured and tracked from dispatch to delivery confirmation.

Contact Information

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