In the world of industrial automation systems, reliability is of utmost importance. The unexpected loss of power can have disastrous consequences. This is where redundant power supplies come into play. But what exactly are they and how do they work? Let’s delve into the practical aspects of redundant power supplies.
Contents
Exploring Redundant Power Supplies
Redundant power supplies are used in applications where ultra-reliability is essential. Take, for example, the control and monitoring of gas turbines in one of the largest oil refineries in the world. To ensure uninterrupted power supply to the electrical components, a set of redundant power supplies is employed.
The Inner Workings
Each redundant power supply unit consists of input and output terminals. The lower terminals are connected to an AC power source, usually 110 or 220 volts. Before reaching the power supplies, protective devices such as surge protection, harmonic filters, and fuses are employed. The ground wire ensures electrical safety.
Powering Up
To activate the power supply, simply connect the AC power to the input terminals. The upper terminals serve as the output terminals, providing a steady 24-volt DC voltage. The red and blue wires connected to the output terminals allow access to the 24-volt DC output.
Current Capacity
Apart from the output voltage, the current rate is another crucial parameter of power supplies. In the case of these power supplies, the current rate is 5 Amps. This means that each power supply can deliver a maximum current of 5 Amps. The current rate should be adjusted according to the requirements of the electrical devices within the enclosure.
Understanding Redundancy
Within a redundant power supply setup, each unit is capable of powering the entire enclosure. However, by setting the output voltage of the primary supply slightly higher than the backup supply, only the primary supply delivers current to the load. If the output voltage of the primary supply drops by more than 0.2 volts, the backup supply takes over. This ensures seamless power delivery even in the event of a primary supply failure.
The Role of Diodes
A diode switching arrangement plays a crucial role in the operation of redundant power supplies. This diode can detect faults and isolate the primary supply from the system output. It then allows the output of the backup supply to flow uninterrupted during the transition. In the absence of internal diodes, an external redundant module can be utilized to achieve the same redundant system functionality.
Monitoring System Health
Each power supply is equipped with an “open contact” that closes when a power supply failure occurs. By connecting the ends of this contact to the PLC input, a signal is sent to the PLC, alerting operators to the problem. This enables prompt action to rectify the issue.
FAQs
Q: Can redundant power supplies be used in residential applications?
A: While redundant power supplies are primarily used in industrial settings, they are not commonly employed in residential applications due to the cost and complexity involved.
Q: Can redundant power supplies prevent all power-related failures?
A: While redundant power supplies greatly enhance reliability, they cannot protect against all types of power-related failures. It is essential to implement additional protective measures such as surge protection and grounding.
Q: Are redundant power supplies energy-efficient?
A: Redundant power supplies are designed for reliability rather than energy efficiency. They may consume slightly more power compared to non-redundant power supplies.
Conclusion
Redundant power supplies are crucial components in ensuring uninterrupted power supply in industrial automation systems. By understanding their inner workings and benefits, engineers can design robust and reliable systems. Remember, in critical applications, redundancy is key.
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Disclaimer: The content provided in this article is for informational purposes only. Techal is not affiliated with any specific redundant power supply brand or manufacturer.
