Siemens 6EP3437-8SB00-0AY0 SITOP Power Supply

The Siemens 6EP3437-8SB00-0AY0 is a SITOP series industrial power supply that delivers a regulated 24V DC output at 20A (480W). It is designed for 3-phase input voltages of 400-500V AC, making it suitable for global industrial applications. This power supply features high efficiency, overload-proof output, and a compact metal housing for DIN rail mounting. It is commonly used to power PLCs, I/O modules, sensors, and other automation components.

Technical Specifications

Input: 3-phase 400-500V AC ±10%, 50/60 Hz, current 1.4A at full load. Efficiency 93% (typ). Output: 24V DC adjustable 22-28V via potentiometer, rated current 20A (at 40°C), 15A at 60°C. Ripple < 150 mVpp. Short-circuit protection: electronic current limiting (constant current) with automatic restart. Overload protection: 120-150% of rated current, shuts down after 5 seconds, auto-restart. Hold-up time: ≥ 20 ms at 400V input. LEDs: green “24V OK”, yellow “overload”. Operating temperature -25°C to +60°C (derated above 40°C). Dimensions: 145 mm (H) x 150 mm (W) x 125 mm (D). Weight approx. 1.8 kg. Protection rating IP20. Screw terminals for input and output.

Key Features

• 3-phase 400-500V AC input, wide range

• 24V DC output, 20A continuous

• High efficiency (93%) reduces heat loss

• Electronic overload and short-circuit protection

• Adjustable output voltage (22-28V DC)

• Parallel operation capability (up to 2 units)

• LED status indicators

• DIN rail mounting (EN 60715)

• UL, CSA, CE, RoHS certified

Construction and Installation

The power supply is housed in a rugged sheet metal case with integrated DIN rail clip. Mount the unit horizontally on a 35 mm DIN rail, ensuring 40 mm clearance above and below for ventilation. Connect the 3-phase input (L1, L2, L3) and protective earth (PE) to the input terminal block (up to 4 mm² wire). The output terminals (+/-) accept up to 10 mm² wire for high current. Use ferrules for stranded wire. The unit includes a green LED for output OK and a yellow LED for current limit active. The output is isolated from input and PE (basic insulation).

Protection and Parallel Operation

The output is short-circuit proof with constant current limiting. If the load impedance is too low, the voltage drops to near zero, and the current is limited to approximately 22A. After removing the fault, the output recovers automatically. For higher power, two identical units can be connected in parallel using the optional decoupling module (6EP1961-2BA20). The parallel configuration provides up to 40A with redundancy.

Applications

This power supply is ideal for large control cabinets with multiple 24V loads such as PLC racks (SIMATIC S7-300, S7-1200, S7-1500), numerous I/O modules, industrial Ethernet switches, and solenoid banks. The 3-phase input balances the load on the mains and reduces harmonic distortion. Typical industries: automotive manufacturing, packaging, material handling, and process automation.

Derating and Environmental Conditions

The 20A rating is valid at 40°C ambient. From 40°C to 60°C, derate linearly to 15A. Above 60°C, do not operate. At altitudes above 2000 m, derate current by 2% per 100 m. The unit can be stored at -40°C to +85°C. Humidity 5-95% non-condensing. Vibration resistance 2g (10-55 Hz).

Certifications and Compliance

The 6EP3437-8SB00-0AY0 is UL 508 listed, CSA C22.2 No. 107.1, and cULus recognized for industrial control equipment. It meets EN 61000-6-2 (industrial immunity) and EN 61000-6-4 (emissions). It is RoHS compliant and bears CE and UKCA marks.

Conclusion

The Siemens SITOP 6EP3437-8SB00-0AY0 delivers reliable, high-current 24V DC power for demanding industrial automation systems. Its 3-phase input, high efficiency, and robust protection features make it a dependable choice for powering sensitive electronics in factory environments.