Siemens 3RT2017-1JB42 Contactor Relay Combination Set 24VDC 12A 3NO

The Siemens 3RT2017-1JB42 Contactor Relay Combination Set is a robust solution designed for reliable control of electrical circuits, offering a 24VDC coil voltage, a 12A switching capacity, and three normally open (NO) contacts. This compact and efficient device excels in demanding industrial environments due to its superior switching performance and long operational life. Its inherent safety features and straightforward integration make it a preferred choice for applications requiring precise and dependable power management.

Product Specifications

| Feature            | Specification                                  |

| :----------------- | :--------------------------------------------- |

| Product Type       | Contactor Relay Combination Set                |

| Manufacturer       | Siemens                                        |

| Model Number       | 3RT2017-1JB42                                  |

| Coil Voltage       | 24V DC                                         |

| Rated Operational Current (AC-1, 400V) | 12 A                                           |

| Number of NO Contacts | 3                                              |

| Number of NC Contacts | 0                                              |

| Auxiliary Contacts | 1 NO + 1 NC (integrated)                       |

| Mounting Type      | DIN rail or screw mounting                     |

| Protection Class   | IP20                                           |

| Operating Temperature | -25 to +60 °C                                  |

Core Features & Market Positioning

The Siemens 3RT2017-1JB42 distinguishes itself through its solid-state control, ensuring rapid switching speeds and reduced wear compared to traditional electromagnetic contactors. Its compact design optimizes panel space, a critical factor in many industrial automation setups. Siemens' reputation for quality and reliability in industrial components further solidifies its market position as a dependable choice for motor control and power switching applications. The integrated auxiliary contacts reduce the need for external wiring, simplifying installation and enhancing system integrity.

Key Application Scenarios

This contactor relay combination set is ideally suited for controlling small to medium-sized motors, heating circuits, and lighting systems in various industrial sectors. Common applications include HVAC systems, pump control, conveyor belt management, and general-purpose switching in machine tools. Its 24VDC coil makes it compatible with many PLC outputs and low-voltage control systems prevalent in modern automation.

Practical System Integration Guidance

Integrating the Siemens 3RT2017-1JB42 is streamlined due to its standard mounting options for DIN rails and screw terminals. For wiring, connect the main circuit power to the line and load terminals, ensuring correct phasing. The control circuit connects to the coil terminals (A1/A2) with the appropriate 24VDC supply. The integrated auxiliary contacts can be wired into control logic for feedback or interlocking purposes. Proper grounding of the enclosure is paramount for safety and operational reliability.

Operation and Risk Mitigation

The 3RT2017-1JB42 operates by energizing its 24VDC coil, which magnetically actuates the power contacts to close the main circuit. De-energizing the coil causes the contacts to open. To mitigate risks, ensure the power supply is de-energized before any wiring or maintenance. Overloading the contactor beyond its 12A rating can lead to overheating and premature failure. Always adhere to local electrical codes and standards during installation and operation. Faulty operation, such as failure to switch, may indicate coil issues or physical obstruction.

Scalability & Long-Term Value

The Siemens 3RT2017-1JB42 is part of Siemens' broader SIRIUS modular system, allowing for easy expansion and integration with other components like overload relays (e.g., 3RU21) and communication modules. This compatibility ensures that systems can be scaled to accommodate growing demands or upgraded with digital functionalities for IIoT integration, such as condition monitoring. Its robust construction contributes to a long service life, providing excellent long-term value and reducing total cost of ownership.

Frequently Asked Questions

What is the primary function of the Siemens 3RT2017-1JB42?

This device acts as an electrically operated switch controlling power circuits. It allows a low-power control signal to switch a higher power load, such as a motor. The 24VDC coil is typically energized by a PLC or other control system.

How do I wire the Siemens 3RT2017-1JB42 for a motor application?

Connect the incoming power supply to the line-side terminals (L1, L2, L3) and the motor to the load-side terminals (T1, T2, T3). Wire the 24VDC control voltage to the coil terminals (A1 and A2) for operation. Ensure proper grounding.

What are the benefits of using a contactor relay like the 3RT2017-1JB42?

It provides electrical isolation between the control and power circuits. Its design offers a long operational life and high switching capacity in a compact form factor. The 24VDC coil is ideal for integration with modern control systems.

Can the 3RT2017-1JB42 be used with AC loads?

While the coil is DC, the power contacts are designed for AC loads up to 12A at 400V (AC-1 rating). Always verify the load type and voltage against the contactor's specifications for safe and effective operation.

What is the significance of the "3NO" designation?

"3NO" means the contactor has three Normally Open (NO) main contacts. These contacts are closed when the coil is energized and open when the coil is de-energized, making it suitable for switching circuits that require a "make" action.

How does the 24VDC coil voltage affect its application?

A 24VDC coil is common in industrial automation, allowing direct interfacing with PLC outputs. It's a safer low-voltage option compared to mains voltage coils, simplifying control wiring and reducing the risk of electrical shock.

What kind of protection is needed for the Siemens 3RT2017-1JB42?

It's essential to protect the contactor from overcurrents using an appropriately sized overload relay or fuse in the main circuit. The contactor itself has an IP20 rating, meaning it requires enclosure protection against solid objects.

What is the difference between a contactor and a relay?

Contactors are generally designed for higher current loads and more frequent switching cycles than relays, often used for motor control. Relays are typically used for lower power loads and control signaling purposes.

How can I troubleshoot a Siemens 3RT2017-1JB42 that isn't switching?

First, verify the 24VDC supply to the coil terminals (A1/A2). Check for any mechanical obstructions or damage to the contacts. Ensure the control signal is present and correctly applied to energize the coil.

What is the role of integrated auxiliary contacts?

The integrated auxiliary contacts (often 1NO + 1NC) provide additional switching points for control logic. They can be used for signaling purposes, such as indicating the contactor's state (on/off) to a PLC or for interlock functions within the control system.