Siemens 3RT7017-1AN21 Medium Power AC Control Contactor 200VAC 12A 3NO

The Siemens 3RT7017-1AN21 is a robust medium-power AC control contactor designed for reliable operation in industrial environments. It features a 200VAC coil voltage, a 12A current rating (AC-3 duty), and includes one normally open (NO) auxiliary contact. This contactor is engineered for efficient motor control and power switching applications, offering a compact size (S00) and straightforward installation via screw terminals or DIN rail mounting. Its design prioritizes safety and operational continuity, making it a dependable component in various automation and control systems.

Product Specifications

| Specification          | Value                                                 |

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

| Manufacturer           | Siemens                                               |

| Series                 | Sirius 3RT70                                          |

| Model Number           | 3RT7017-1AN21                                         |

| Type                   | AC Control Contactor                                  |

| Coil Voltage           | 200 VAC (50/60 Hz)                                    |

| Current Rating (AC-3)  | 12 A                                                  |

| Power Rating (AC-3)    | 5.5 kW @ 400V                                         |

| Number of Poles        | 3                                                     |

| Auxiliary Contacts     | 1 NO (Normally Open)                                  |

| Terminal Type          | Screw Terminals                                       |

| Mounting               | DIN Rail or Screw Mount                               |

| Enclosure Protection   | IP20 (front face)                                     |

| Dimensions (H x W x D) | 57.5 mm x 45 mm x 72 mm                               |

| Contactor Reliability  | Suitable for PLC control (17V, 5mA)                   |

| Short-Circuit Protection (Type 1) | gL/gG NH 3NA: 35 A                                    |

| Short-Circuit Protection (Type 2) | gL/gG NH 3NA: 20 A                                    |

| Short-Circuit Protection (Auxiliary) | Fuse gL/gG: 10A                                       |

Core Features & Market Positioning

The Siemens 3RT7017-1AN21 positions itself as a dependable and versatile component within the industrial automation landscape. Its S00 size offers a compact footprint, crucial for control cabinets where space is at a premium. The inclusion of a pre-integrated normally open auxiliary contact streamlines basic control configurations, reducing the need for separate add-on modules in simpler applications. Compared to other offerings, the 3RT7017-1AN21 benefits from Siemens' established reputation for quality and durability in industrial control gear. Its compatibility with a wide range of Siemens Sirius accessories, such as overload relays and additional auxiliary contact blocks, enhances its flexibility for more complex motor starter assemblies. The use of screw terminals provides a secure and reliable connection method, favored in many industrial settings for its robustness and ease of maintenance.

Key Application Scenarios

This Siemens contactor, the 3RT7017-1AN21, is ideally suited for controlling and switching medium-power AC motors in various industrial sectors. Common applications include the direct on-line (DOL) starting of three-phase motors used in pumps, fans, compressors, and conveyors within manufacturing plants, processing facilities, and building automation systems. Its 12A AC-3 rating makes it suitable for loads where the motor draws significant current during startup. The integrated NO auxiliary contact can be utilized for signaling the contactor's state (e.g., running or stopped) to a PLC or a local indicator. It is also a viable choice for switching non-inductive loads within its current and voltage limits, such as heating elements or lighting circuits where reliable switching is paramount.

Practical System Integration Guidance

Integrating the Siemens 3RT7017-1AN21 into an industrial control system is a straightforward process. For power connections, the main terminals are designed for robust screw connections, accepting wire cross-sections typically ranging from 0.5 mm² to 4 mm² for single or multi-core cables. For auxiliary circuits, similar screw terminals offer flexibility for control wiring. When mounting, the contactor can be securely fastened to a standard 35mm DIN rail or directly to a panel using screws. For motor control applications, it is essential to pair the 3RT7017-1AN21 with an appropriately sized thermal or electronic overload relay to provide motor protection against overcurrents. Wiring diagrams for specific motor starters can be found in Siemens' technical documentation for the Sirius range, ensuring correct interconnection of the contactor, overload relay, and control circuit.

Operation and Risk Mitigation

The Siemens 3RT7017-1AN21 operates by using its 200VAC coil to energize an electromagnet, which in turn closes the main power contacts, allowing current to flow to the load. Conversely, de-energizing the coil causes a spring mechanism to open the contacts, interrupting the power flow. To mitigate risks, always ensure the power supply is de-energized before performing any wiring or maintenance. The contactor is designed with touch-proof front-facing terminals (IP20) to prevent accidental contact with live parts during operation. Proper selection and coordination with overload relays are critical for protecting the motor and preventing damage due to overloads or short circuits. Following the short-circuit protection guidelines, such as using a 35A fuse for Type 1 coordination or a 20A fuse for Type 2, is essential for system safety.

Scalability & Long-Term Value

The Siemens 3RT7017-1AN21 offers significant scalability and long-term value within the Sirius industrial control platform. Its modular design allows for the easy addition of auxiliary contact blocks (e.g., 2NO+2NC configurations) to expand its control capabilities for more complex logic. Compatibility with Siemens' range of overload relays (thermal and electronic) ensures that motor protection can be tailored and upgraded as motor requirements evolve. Furthermore, Siemens' commitment to backward compatibility means that components like the 3RT7017-1AN21 can often integrate seamlessly into existing Sirius installations, protecting investments in control infrastructure. For future-proofing, the Sirius system is designed with an eye toward Industry 4.0, with many components supporting digital integration and IIoT connectivity through appropriate gateways and software solutions.

Frequently Asked Questions (FAQs)

Q1: What is the maximum power that the Siemens 3RT7017-1AN21 can control?

The Siemens 3RT7017-1AN21 is rated for 12A under AC-3 duty conditions. This translates to a maximum power handling capacity of 5.5 kW when operating at 400V.

This rating is crucial for applications involving direct switching of squirrel-cage motors. Always ensure the motor's full-load current does not exceed this 12A limit.

For loads with higher inrush currents or different duty cycles, a proper engineering assessment and potentially a larger contactor may be necessary.

Q2: Can I use the 3RT7017-1AN21 for DC loads?

While primarily designed for AC control, some contactors can be adapted for DC switching with derating. However, the 3RT7017-1AN21 is specifically optimized for AC circuits.

Using it for DC loads might require special considerations or derating factors not explicitly stated for this model. It is recommended to consult Siemens' application notes or a qualified engineer.

For dedicated DC applications, using contactors specifically designed for DC switching is generally advisable to ensure reliability and safety.

Q3: What is the function of the '1NO' auxiliary contact?

The '1NO' indicates one normally open auxiliary contact integrated into the contactor. This contact closes when the main power contacts engage.

This auxiliary contact is invaluable for control signaling, such as confirming the contactor's activation to a PLC or illuminating an indicator light.

It provides feedback on the contactor's status, enabling more sophisticated control logic and monitoring within the automation system.

Q4: How do I wire the Siemens 3RT7017-1AN21?

Power connections are made to the main terminals using screw clamps, typically for wires from 0.5 to 4 mm². Ensure correct polarity for AC connections.

The auxiliary contact also uses screw terminals for its control wiring. Refer to the terminal markings on the contactor for correct identification of NO and NC contacts.

Always disconnect power before wiring and follow local electrical codes and best practices for secure and safe connections.

Q5: Is this contactor suitable for frequent switching operations?

Yes, Siemens contactors like the 3RT7017-1AN21 are built for industrial use, including frequent switching. Its design ensures a long operational life under typical conditions.

The precise switching frequency depends on the load type, ambient temperature, and other environmental factors. Consult the product datasheet for specific endurance ratings.

For extremely high-frequency applications, specialized contactors or solid-state relays might offer superior longevity.

Q6: What overload protection should I use with the 3RT7017-1AN21?

The 3RT7017-1AN21 requires an external overload relay for motor protection. Siemens offers various thermal and electronic overload relays compatible with this contactor.

Select an overload relay with a trip current rating appropriate for the motor being protected. This ensures safe operation by detecting overcurrent conditions.

Properly coordinating the contactor and overload relay is crucial for reliable motor starting and protection against faults.

Q7: Can I add more auxiliary contacts to the 3RT7017-1AN21?

Yes, the 3RT7017-1AN21 is part of the modular Sirius range and can accommodate additional auxiliary contact blocks. These can be mounted on the front or side.

Siemens provides various auxiliary contact blocks, allowing configuration with multiple NO and NC contacts as needed for complex control logic.

This modularity enhances the contactor's versatility, enabling it to be adapted for evolving system requirements without replacing the entire unit.

Q8: What is the operating temperature range for this contactor?

The 3RT7017-1AN21 is designed to operate reliably in various climates. Specific temperature ratings are available in the detailed technical datasheet from Siemens.

Generally, industrial contactors operate within a range of -25°C to +60°C, though performance may vary at the extremes. Ensure adequate ventilation.

Maintaining the contactor within its specified operating temperature range is vital for its longevity and consistent performance.

Q9: Does the 3RT7017-1AN21 have overload protection built-in?

No, the 3RT7017-1AN21 itself does not have integrated overload protection. It serves as the switching device for the motor circuit.

Overload protection must be provided by a separate, appropriately sized overload relay, which is typically mounted adjacent to or integrated with the contactor.

This separation allows for tailored protection based on motor characteristics and ensures the contactor is not subjected to damaging overcurrents.

Q10: Where can I find the official datasheet and technical documentation?

Official datasheets and comprehensive technical documentation for the Siemens 3RT7017-1AN21 can be found on the Siemens Industry Online Support portal.

You can also access product catalogs and download technical specifications directly from Siemens' SiePortal or through authorized distributors' websites.

Searching for "Siemens 3RT7017-1AN21 datasheet" on Siemens' official website or a reliable industrial component distributor will lead you to the necessary resources.