Use a Modular Approach to Motor Control Panels

When building a motor control panel, it can be challenging to optimize the layout. Breakers, contactors, and other components come in all shapes and sizes. This can lead to a messy design that is difficult to install, expand, and maintain.

The SIRIUS Modular system from Siemens simplifies this process. Whether a small installation or a complex industrial system, the uniformity across sizes and the ability to mix and match components makes customization straightforward. This flexibility streamlines design and reduces the time and cost associated with installing or modifying new systems.

A space-saving, simplified design

One of the standout features of the SIRIUS system is its compact footprint. Components like motor starter protectors and contactors are designed to take up minimal space in control cabinets, which is crucial in industrial environments where space is at a premium. The shared accessories across component sizes further simplify system design, allowing for higher packing density without compromising functionality.

The SIRIUS system offers pre-wired load feeders and tool-free connections to minimize installation complexity. This speeds up installation and reduces the risk of wiring errors, which can be costly in terms of labor and system downtime. The spring-loaded connections ensure a reliable, vibration-resistant setup that doesn’t require regular maintenance, improving overall system reliability.

Installation has been simplified in the digital domain as well. The SIRIUS modular system integrates with automation protocols like IO-Link and AS-Interface, allowing for seamless communication between motor control systems and higher-level automation. This integration improves monitoring, making it easier to identify potential issues and optimize performance.

To better understand the capabilities of the SIRIUS modular system, let’s take a closer look at some of the available modules.

Flexible motor starter protector circuit breakers

SIRIUS MSP circuit breakers (Figure 1) safeguard motors by combining overload and short-circuit protection in a single device. Key technical features include adjustable trip settings to match motor requirements, allowing for precision protection. They offer breaking capacities up to 100 kiloamperes (kA) and are designed to integrate seamlessly with SIRIUS contactors, providing compact, efficient motor protection in high-demand environments like manufacturing and HVAC systems. Their flexibility in handling AC and DC currents enhances their versatility in different industrial setups.

Figure 1: The SIRIUS MSP circuit breakers combine overload and short-circuit protection in a single device and offer up to 100 kA breaking capacities. (Image source: Siemens)

Low-power, high-endurance contactors

SIRIUS 2 contactors (Figure 2) are designed for high-endurance switching, with a mechanical life rated for up to 10 million operations. They are available with conventional AC/DC as well as solid-state AC/DC operating mechanism options, and support loads up to 37 kilowatts (kW). The low-power coil technology reduces real power loss to only 4 watts, making them efficient in conveyors, pumps, and machinery applications. They feature screw and spring-loaded terminal options, providing flexibility for various installation preferences.

Figure 2: The SIRIUS 2 contactors have a mechanical life of 10 million operations and support loads up to 37 kW. (Image source: Siemens)

Compact, reliable control relays

SIRIUS 2 control relays (Figure 3) are optimized for reliable low-voltage signal switching. They are available in 4 and 8-pole configurations, have a mix of normally-open and normally-closed contacts, and support a range of AC and DC voltages to provide broad application support in control circuits. These relays feature compact designs for space-constrained control panels and boast a high mechanical lifespan up to 30 million operations, ensuring long-term reliability in automation systems. Fail-safe variants further enhance operational security in critical applications.

Figure 3: The SIRIUS 2 control relays for low-voltage signal switching handle control voltages in 4 and 8-pole configurations. (Image source: Siemens)

High-capacity reversing contactors

SIRIUS 3RA23 reversing contactors (Figure 4) enable control of motors in forward and reverse directions, which is ideal for material handling and conveyor systems. They include a mechanical interlock to prevent simultaneous activation of both directions, while their pre-wired solutions simplify installation and minimize wiring errors. These contactors can switch large loads up to 55 kW, which is particularly beneficial in applications requiring frequent directional changes.

Figure 4: The SIRIUS 3RA23 reversing contactors allow control of motors in forward and reverse directions. (Image source: Siemens)

High-performance, long-life thermal overload relays

SIRIUS 3RU2 thermal overload relays (Figure 5) protect motors by sensing prolonged overload conditions. Their bimetallic trip units provide precise protection by adjusting trip settings (Class 10 or Class 20) to match motor characteristics, enhancing performance and lifespan. These relays integrate seamlessly with SIRIUS contactors and offer manual or automatic reset options, providing flexibility in applications like pumps, fans, and compressors, where motors often operate under heavy loads for extended periods.

Figure 5: The SIRIUS 3RU2 thermal overload relays protect motors by sensing prolonged overload conditions. (Image source: Siemens)

Conclusion

The Siemens SIRIUS modular system offers a flexible, efficient, and reliable approach to motor control and protection. With advanced features like adjustable trip settings, low-power operation, and seamless integration with automation protocols, the SIRIUS system provides engineers with the tools to optimize industrial performance. Its focus on space-saving design, ease of installation, and long-term reliability ensures that the system can meet the needs of both modern and evolving industrial environments.