Siemens 1FK7100-2AF71-1RH1 Servo Motor: Product Overview, Technical Parameters, Applications, Advantages, and Related Models

1. Product Introduction

The Siemens 1FK7100-2AF71-1RH1 is a permanent-magnet synchronous servo motor in the SIMOTICS S 1FK7 Compact family, designed for industrial motion-control applications. It is intended for machinery that requires reliable torque, controlled speed, accurate position feedback, and repeatable movement during automated production cycles.

The motor has an optimum operating power of 3.8 kW and an optimum operating speed of 3,000 rpm. Its rated torque is 12.0 Nm at the specified 100 K temperature-rise condition, while its static torque at the same temperature-rise condition is 18.0 Nm.

The RH1 configuration features a 20-bit single-turn plus 12-bit multi-turn absolute encoder with a DRIVE-CLiQ interface. It also includes an integrated permanent-magnet holding brake, a smooth shaft with tolerance N, natural cooling, a rotatable power connector, and IP65 protection.

These features make the motor suitable for a range of automated machines where controlled movement and reliable position feedback are required. The integrated brake is an important distinction from otherwise similar versions without a brake, particularly when a machine axis needs to remain stationary under specified conditions.

The motor is designed to operate as part of a compatible servo-drive system. Correct selection therefore requires more than matching power and speed: the drive interface, encoder, brake supply, shaft dimensions, mounting arrangement, and machine load must also be considered.

2. Brand and Product Series

The SIMOTICS S 1FK7 Compact family is designed for industrial motion-control tasks where the motor needs to operate in coordination with a servo drive and machine controller. Its configuration options allow engineers to select motors with different feedback devices, brake arrangements, and mechanical features.

The complete model number is essential when purchasing a replacement. Motors that share the same frame size and basic performance ratings can still differ in encoder type, brake equipment, connector configuration, or protection details.

3. Detailed Technical Specifications

The following tables summarize the main technical characteristics of the 1FK7100-2AF71-1RH1. The core performance data and configuration are identified separately from installation dimensions that must be confirmed using the exact mechanical drawing.

3.1 Basic Electrical and Performance Parameters

The rated torque and static torque describe different operating conditions. The rated torque of 12.0 Nm is the reference continuous operating torque at the specified temperature-rise condition. The static torque of 18.0 Nm describes the motor’s stationary torque capability under its stated thermal conditions.

The maximum torque of 55.0 Nm is a limiting value and should not be interpreted as a continuous operating rating. The actual torque available depends on speed, current limits, drive configuration, temperature, and the duration of the load.

3.2 Electrical Constants and Dynamic Characteristics

These electrical characteristics are useful when matching the motor to a drive and estimating the response of the complete motion-control system.

The torque constant indicates the relationship between motor current and generated torque. The winding resistance and inductance influence electrical losses and current regulation, while the rotor moment of inertia affects acceleration and deceleration behavior.

For a machine with frequent starts and stops, the reflected load inertia and the required cycle time should be calculated before finalizing the motor and drive selection. A suitable combination helps the system achieve stable operation without excessive current demand or prolonged settling time.

3.3 Mechanical Specifications and Dimensions

The 100 mm shaft height identifies the motor’s frame size, not its complete external height. Overall length, flange diameter, shaft diameter, shaft extension, bolt-hole pattern, and connector clearance must be taken from the exact mechanical drawing.

For machine replacement work, these measurements should be checked against the installed motor before ordering. A similar frame size does not guarantee that the motor will fit the existing mounting plate or coupling.

3.4 Encoder and Feedback Specifications

The absolute encoder supplies position information to a compatible drive. The single-turn component identifies the angular position within one revolution, while the multi-turn component tracks position across multiple revolutions within the encoder’s specified range.

This configuration is useful in applications where the control system needs absolute position information rather than relying solely on incremental position counting. Correct wiring, drive support, and parameterization remain essential for proper operation.

3.5 Holding-Brake Specifications

The integrated holding brake is intended to maintain a stationary axis when the motor is not actively generating torque. It can be particularly useful in positioning equipment and applications where a stationary shaft must resist movement.

The holding brake should not automatically be treated as an emergency stopping device. Its holding torque, switching frequency, permissible braking work, electrical supply, and control sequence must be suitable for the application.

For a vertical axis, the brake must be assessed together with the load, transmission ratio, gravity torque, and mechanical safety provisions. The brake is one part of the machine’s overall load-retention arrangement.

3.6 Installation and Operating Conditions

4. Product Functions and Operating Principle

4.1 Permanent-Magnet Synchronous Technology

The motor uses permanent magnets in its rotor and controlled currents in the stator to generate torque. A compatible servo drive regulates current and electrical phase to control the motor’s movement.

This design supports applications that require controlled acceleration, deceleration, speed regulation, and positioning. Rather than running only at a fixed speed, the motor can follow motion commands defined by the machine controller.

4.2 Absolute Encoder Feedback

The RH1 configuration uses a 20-bit single-turn and 12-bit multi-turn absolute encoder with a DRIVE-CLiQ interface. The drive uses this feedback to obtain motor-position information and regulate movement.

Absolute feedback can be valuable in automated machinery where the control system needs reliable position information. However, the encoder’s interface and parameters must match the drive. A motor with an incompatible feedback system may require a different drive or a different motor configuration.

4.3 Integrated Holding Brake

The permanent-magnet holding brake helps keep the motor shaft stationary when the brake is engaged. It can support positioning axes and mechanisms that need to remain in place while the drive is not generating torque.

The brake should be operated according to its specified limits. For applications with gravity loads, the required holding capacity must be calculated from the actual load and transmission arrangement.

4.4 Natural Cooling

Natural cooling transfers heat through the motor housing into the surrounding air. This can simplify installation because the motor does not rely on a dedicated external fan as its primary cooling method.

The motor nevertheless requires sufficient ventilation. High ambient temperature, restricted airflow, frequent acceleration, and sustained high torque can increase winding temperature and reduce the permissible operating load.

4.5 Smooth Shaft Design

The smooth shaft with tolerance N is intended for a compatible coupling or mechanical connection. A suitable clamping-style coupling can provide a secure connection when it matches the shaft dimensions and the application’s torque requirements.

The coupling must be aligned correctly, and permissible radial and axial loads must be respected. Poor alignment or an unsuitable coupling can cause vibration, additional bearing loads, and premature mechanical wear.

5. Main Applications

5.1 CNC Machine Tools and Machining Equipment

The motor can be considered for compatible feed axes, positioning mechanisms, and automated machining systems. Servo control allows the machine to regulate speed and follow defined motion profiles.

For CNC applications, the required torque, acceleration, axis inertia, cutting forces, and cycle time must be evaluated. The encoder and drive configuration must also be compatible with the machine’s motion-control architecture.

5.2 Packaging and Filling Machinery

Packaging equipment uses servo motors for feeding, indexing, cutting, sealing, and transfer operations. These processes often require repeated movement with controlled acceleration and predictable stopping positions.

The RH1 motor’s absolute encoder can support position-based control, while the holding brake can help maintain a stationary position when the machine’s operating sequence requires it. The actual motor selection should be based on the load and production cycle.

5.3 Automated Assembly Lines

Automated assembly machinery may use servo motors for component positioning, transfer, feeding, and controlled movement between stations.

The motor can be evaluated for these tasks when its rated torque, speed, feedback interface, and mechanical configuration match the application. Repeatability and positioning performance also depend on the transmission, machine rigidity, drive tuning, and control software.

5.4 Printing and Converting Equipment

Printing, labeling, and converting machines often require synchronized roller motion, controlled material feeding, and accurate indexing.

The absolute encoder supports position-aware motion control when paired with a compatible drive. The complete system must be configured to meet the required speed profile and synchronization accuracy.

5.5 Material Handling and Positioning Systems

Servo motors can operate transfer mechanisms, indexing tables, feeders, and positioning stages. These systems frequently need controlled movement between predefined positions.

The integrated holding brake can be useful where the axis must remain stationary under specified conditions. For vertical or gravity-loaded mechanisms, the brake’s holding capacity and the machine’s mechanical safety provisions must be checked carefully.

5.6 Automated Production Machinery

The motor can be considered for feed axes, adjustment mechanisms, positioning units, and other automated equipment requiring repeatable movement.

The 1FK7 Compact family provides different configurations for various drive and mechanical requirements. The correct motor should be chosen based on the actual load profile, operating environment, feedback system, and mounting constraints.

6. Product Advantages

6.1 Compact Industrial Design

The motor’s compact construction can help machine designers integrate servo motion into a defined installation space. Its 100 mm shaft-height frame is suitable for machinery designed around the corresponding mounting dimensions.

The actual space requirement also depends on the connector arrangement, cable routing, brake configuration, and required service clearance.

6.2 Absolute Position Feedback

The 20-bit single-turn and 12-bit multi-turn encoder provides absolute position information through the DRIVE-CLiQ interface.

This can support accurate position control and simplify the feedback architecture in compatible systems. Proper drive support and configuration are necessary to obtain the intended performance.

6.3 Integrated Holding Brake

The RH1 configuration includes a permanent-magnet holding brake. This can help maintain the shaft’s stationary position when the motor is not actively producing torque.

The brake is especially relevant when comparing the RH1 with a similar model that does not include a brake. Brake torque and electrical requirements must be checked for the actual application.

6.4 Controlled Torque and Speed

When paired with a compatible servo drive, the motor can follow controlled speed and torque commands. This is useful for equipment that repeatedly accelerates, decelerates, indexes, or synchronizes with other machine axes.

The achievable performance depends on motor sizing, drive capacity, feedback compatibility, mechanical rigidity, and correct control tuning.

6.5 Natural Cooling

Natural cooling can simplify machine integration by avoiding the need for a dedicated external fan as the primary cooling method.

Adequate airflow and operation within the specified thermal limits remain necessary. The motor’s rated performance should be assessed against the actual duty cycle and ambient conditions.

6.6 IP65 Protection

The IP65 rating provides dust protection and resistance to water jets under the applicable test conditions. This can be useful in many industrial environments.

IP65 does not mean the motor can be immersed in water or exposed to every cleaning process or chemical. The environment should be evaluated before installation.

6.7 Rotatable Power Connector

The rotatable power connector can make cable routing easier where space is limited. It allows the connector orientation to be adjusted to suit the machine layout.

Cables must still be routed within their permitted bending radius and protected from tension, abrasion, and interference with moving parts.

6.8 Compatibility with Industrial Motion-Control Systems

The motor belongs to the 1FK7 family for SINAMICS S120 Combi drive systems. This provides a defined starting point for selecting a compatible drive and feedback arrangement.

The exact drive model, current capacity, voltage class, feedback support, and motor parameters should all be verified before commissioning.

7. Five Related Models in the Same Series

The following models are relevant comparison candidates within the 1FK7 family. The RH1 is the target brake-equipped version, while the RG1 is a closely related version without an integrated holding brake. Other configurations may differ in encoder resolution or feedback arrangement.

Specifications marked as reference values should be verified against the complete ordering code before purchase.

Related Model Selection Notes

1FK7100-2AF71-1RG1 is the closest comparison when the machine does not require an integrated holding brake. Its core operating ratings are similar to the RH1 version, but the absence of the brake affects the motor’s function and weight.

1FK7100-2AF71-1CG1 is worth evaluating when a higher-resolution absolute encoder configuration is required. The drive must support the specified encoder interface, and the machine’s feedback configuration must be checked.

1FK7100-2AF71-1PH2 is a brake-equipped alternative with a different feedback configuration. It may be relevant when a resolver-based system is required, but the drive and feedback wiring must match the selected motor.

1FK7100-2AF71-1UH1 should be considered only after its precise feedback and mechanical configuration have been verified. Similar ordering codes do not guarantee that two models have identical electrical or mechanical features.

For all five models, the exact overall dimensions and configuration-specific weight should be confirmed before ordering. The 100 mm shaft height is a frame reference and does not replace the full mechanical drawing.

8. Five Other Siemens Servo-Motor Models to Consider

The following alternatives broaden the selection to other frame sizes or a different servo-motor family. They can be used for initial engineering comparisons, but they should not be treated as direct replacements without checking their complete specifications.

How to Evaluate These Alternatives

1FK7083-5AF71-1AG0: This model is worth considering where the machine design supports the corresponding 1FK7 frame size. Its shaft dimensions, feedback interface, brake configuration, and torque capacity must be checked against the RH1.

1FK7080-5AF71-1AG0: A smaller-frame motor may help reduce installation space, but it may not provide the same torque capacity or thermal performance. The load requirements must be recalculated before considering a substitution.

1FK7063-5AF71-1AG0: This smaller-frame option may be appropriate for lower-load applications. It should not be selected for a demanding axis merely because its speed rating appears similar.

1FK7100-2AF71-1CG1: This is the closest same-frame comparison in the table. Its different encoder configuration makes feedback compatibility the primary point to check.

1FT6086-8AH71-3EG1: This belongs to a different servo-motor family and should be treated as an alternative for engineering evaluation. Mounting dimensions, rated torque, feedback, drive compatibility, and brake requirements must all be established.

For models whose exact ratings are not specified here, the complete technical data should be checked before procurement. Power, torque, dimensions, and weight should not be estimated solely from a similar model number.

9. Installation and Maintenance Recommendations

9.1 Confirm the Complete Ordering Code

Record the full motor model number and compare it with the existing unit’s nameplate. Differences in the final characters may indicate a different encoder, brake, shaft, or protection configuration.

9.2 Verify Drive Compatibility

Confirm that the selected drive supports the motor’s electrical characteristics and DRIVE-CLiQ feedback interface. The motor data, encoder parameters, and feedback connection must be correctly configured before commissioning.

9.3 Check the Mechanical Dimensions

Confirm the mounting flange, bolt-hole pattern, shaft diameter, shaft extension, overall length, and connector clearance using the exact drawing. The 100 mm shaft height alone is not sufficient to establish mechanical compatibility.

9.4 Evaluate Torque and Inertia

Calculate the continuous torque, peak torque, acceleration, deceleration, and reflected load inertia. The motor and drive should be selected for the complete operating cycle rather than the nominal power rating alone.

9.5 Test the Holding Brake

Check the brake’s electrical supply, release and engagement sequence, and holding capacity according to the specified requirements. For vertical axes, evaluate the load-retention arrangement and any additional mechanical safety measures required.

9.6 Maintain Suitable Cooling

Provide sufficient airflow around the motor and ensure that the installed motor remains within its specified ambient and thermal limits. Restricted airflow and repeated high-torque operation can increase temperature.

9.7 Inspect the Connectors and Coupling

Inspect power and feedback cables, connector condition, mounting bolts, and the shaft coupling during scheduled maintenance. Correct cable routing and shaft alignment help reduce faults, vibration, and unnecessary mechanical wear.

10. Product Summary

The Siemens 1FK7100-2AF71-1RH1 is a brake-equipped synchronous servo motor in the SIMOTICS S 1FK7 Compact family. Its key characteristics include 3.8 kW optimum power, 3,000 rpm operating speed, 12.0 Nm rated torque, 18.0 Nm static torque at the 100 K condition, natural cooling, IP65 protection, and a 20-bit single-turn plus 12-bit multi-turn absolute encoder with DRIVE-CLiQ.

The integrated permanent-magnet holding brake is a major feature of the RH1 configuration. Combined with absolute feedback and a rotatable power connector, it makes the motor a candidate for industrial automation systems requiring controlled motion and a defined holding function.

Before ordering or installing the motor, confirm the drive interface, encoder compatibility, brake requirements, shaft dimensions, mounting arrangement, and exact mechanical drawing. Related 1FK7 models can offer similar ratings with different feedback or brake configurations, but direct substitution should only be made after electrical and mechanical compatibility has been established.