6GK5791-2AC00-0AA0 10W AC/DC Power Supply PS791-2AC

Introduction to the Siemens 6GK5791-2AC00-0AA0

When your SCALANCE W786 wireless access point needs reliable power in harsh environments, the Siemens 6GK5791-2AC00-0AA0 power supply PS791-2AC is engineered to deliver. This AC/DC power supply unit converts 90-240 V AC input to a stable 18 V DC output, providing 10 W of power (typical 14.4 W). Designed for outdoor or industrial use, it operates in temperatures from -40 °C to +60 °C and carries an IP65 protection rating, making it dust-tight and protected against water jets.

As part of the Siemens SCALANCE W family, this power supply is specifically intended for use with SCALANCE W786 devices. Its compact dimensions—133 mm wide, 45 mm high, and 30 mm deep—allow for easy integration into existing enclosures. With a net weight of only 0.209 kg, it adds minimal bulk to your installation.

Key Features and Technical Specifications

The 6GK5791-2AC00-0AA0 delivers consistent performance across a wide input voltage range. Here are the core specifications extracted from the official datasheet:

• Input voltage: 90-240 V AC (rated 100-240 V AC)
• Output voltage: 18 V DC (rated value)
• Power rating: 10 W (typical supplied active power 14.4 W)
• Line frequency: 45-65 Hz
• Buffering time: Minimum 20 ms at rated output current
• Protection class: VDE 0805, VDE 0100
• Connections: 3-pole screw-type terminal for AC input, 4-pin connector for DC output
• Ambient temperature: -40 °C to +60 °C during operation
• Protection class: IP65

One distinctive feature is the buffering time of at least 20 ms, which ensures that momentary power interruptions do not disrupt your SCALANCE W786 operation. This is critical for maintaining network connectivity in industrial settings where power stability is not guaranteed.

Applications and Use Cases

Its wide operating temperature range and IP65 rating allow deployment in unheated enclosures or directly on machinery where vibration and moisture are present.

For engineers planning a wireless network in a harsh environment, this power supply ensures that your access point receives clean, regulated DC power. The 18 V DC output matches the requirements of SCALANCE W786, so you avoid compatibility issues that can arise with generic power supplies.

Installation and Setup

Installing the 6GK5791-2AC00-0AA0 is straightforward, but follow these guidelines for best results. First, verify that your AC source is within the 90-240 V AC range and that the frequency is between 45 and 65 Hz. Use the 3-pole screw-type terminal for the AC input, ensuring a secure connection. For the DC output, use the 4-pin connector to attach to your SCALANCE W786.

Mount the unit in a location that allows adequate airflow and does not exceed the -40 °C to +60 °C operating temperature. The IP65 rating means it is protected against dust and water, but avoid submerging or exposing it to high-pressure washdowns beyond what IP65 specifies.

Maintenance and Reliability

Routine maintenance for the 6GK5791-2AC00-0AA0 is minimal due to its rugged design. Periodically inspect the terminal connections for tightness and check for any signs of corrosion or damage, especially in outdoor installations. Verify that the ambient temperature remains within the specified range, as extreme heat can reduce the lifespan of electronic components.

Because this power supply is designed for continuous operation, it contributes to reduced downtime in your network. The buffering time of 20 ms helps ride through brief power dips, preventing unexpected reboots of your access point.

Compatibility and Integration

The 6GK5791-2AC00-0AA0 is specifically designed for use with SCALANCE W786 devices. It is not intended for other equipment, so ensure you pair it only with compatible SCALANCE W786 models. The power supply includes operating instructions in German and English, which provide detailed wiring and safety information.

For integration into a larger industrial network, this power supply works with any SCALANCE W786 access point, allowing you to power remote wireless nodes without running long DC cables. This simplifies installation and improves reliability.

Troubleshooting Common Issues

If your SCALANCE W786 does not power up, first check the AC input voltage at the terminal. Ensure it is within 90-240 V AC. Next, verify the DC output voltage at the 4-pin connector; it should be 18 V DC. If the output is absent, check the buffering time—if power interruptions exceed 20 ms, the supply may need time to recover.

Another common issue is loose connections. Tighten the screw-type terminals and ensure the 4-pin connector is fully seated. If the unit operates outside the -40 °C to +60 °C range, it may shut down to protect itself; move it to a more suitable location.

Product Support and Availability

At AutoDCSTech, we stock the Siemens 6GK5791-2AC00-0AA0 power supply for immediate shipment. Our team can assist you with technical questions and ensure you get the right part for your SCALANCE W786 system. Contact us for current availability and lead times.