Siemens 1FK7100-2AF71-1RG1 Servo Motor: Product Description, Technical Parameters, Applications, Advantages, and Related Models

1. Product Introduction

The Siemens 1FK7100-2AF71-1RG1 is a SIMOTICS S synchronous servo motor belonging to the 1FK7 Compact family for SINAMICS S120 Combi drive systems. It is designed for industrial automation applications requiring controlled motion, stable torque delivery, accurate speed regulation, and repeatable positioning.

This motor has an optimum operating power of approximately 3.8 kW and an optimum operating speed of 3,000 rpm. Its permanent-magnet synchronous design supports servo-drive control of speed, torque, and position, making it suitable for a range of automated machines and production equipment.

The RG1 configuration is specified with a 20-bit single-turn plus 12-bit multi-turn absolute encoder featuring a DRIVE-CLiQ interface. It has a smooth shaft with tolerance N, natural cooling, an IM B5 mounting arrangement, a rotatable power connector, and IP65 protection. The specified configuration does not include a holding brake.

These characteristics make the motor a candidate for machine axes that need accurate feedback and controlled movement without requiring an integrated holding brake. The exact application suitability depends on the load, drive, mechanical transmission, duty cycle, and environmental conditions.

2. Brand and Product Series

The SIMOTICS S 1FK7 family is designed for industrial motion-control tasks where the motor must work as part of a coordinated drive system. The 1FK7100 frame designation identifies a particular motor size, while the remaining ordering-code characters identify the selected electrical and mechanical configuration.

For maintenance and replacement purposes, the complete model number is important. Motors with similar frame sizes may use different feedback devices, shaft configurations, brake options, or protection arrangements. A matching power rating alone does not establish interchangeability.

3. Detailed Technical Specifications

The following specifications describe the 1FK7100-2AF71-1RG1 configuration. Values such as current, torque, speed, encoder type, protection rating, and weight should be used as the main selection references. Overall mechanical dimensions must be taken from the matching installation drawing.

3.1 Basic Electrical and Performance Parameters

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 is a separate thermal operating value and should not be interpreted as the torque available continuously at every speed.

The maximum torque of 55.0 Nm is a limiting value, not a continuous operating rating. Whether the motor can deliver a particular torque depends on the drive, current limits, speed, temperature, and duration of the load.

3.2 Electrical Constants and Dynamic Characteristics

These parameters help determine how the motor responds to changing commands and how it should be paired with a servo drive. The torque constant relates motor current to generated torque, while the winding resistance and inductance influence the electrical behavior of the motor and the drive’s current regulation.

The rotor moment of inertia is particularly important in applications with frequent acceleration and deceleration. A machine with a high reflected load inertia may require careful tuning of the motor-to-load inertia ratio to maintain stable motion and acceptable settling time.

3.3 Mechanical Specifications and Dimensions

The 100 mm shaft height identifies the motor’s frame size; it is not the complete external height. The overall length, flange dimensions, shaft diameter, mounting-hole pattern, and connector clearance must be checked against the exact mechanical drawing before installation.

The specified IP65 protection rating indicates protection against dust ingress and water jets under the applicable test conditions. It does not mean that the motor is suitable for immersion or every washdown environment.

3.4 Encoder and Feedback Specifications

The absolute encoder provides position information that can be used by a compatible drive to control the motor’s movement. Its multi-turn capability records position across multiple revolutions within the encoder’s specified operating range.

DRIVE-CLiQ compatibility is an important selection factor. A motor with a different feedback interface may not be a direct replacement, even if its power, speed, and frame size are similar.

3.5 Operating and Installation Conditions

Because this configuration has no integrated holding brake, applications involving vertical axes or loads that could move when power is removed need particular attention. The machine designer should determine whether an external brake or another suitable load-retention arrangement is necessary.

4. Product Functions and Operating Principle

4.1 Permanent-Magnet Synchronous Technology

The motor uses permanent magnets in the rotor and controlled electrical currents in the stator to generate rotational torque. A compatible servo drive regulates the current and electrical phase to produce the requested torque and motion.

This design is well suited to industrial machinery that needs more than simple continuous rotation. The drive can command the motor to accelerate, decelerate, maintain a specified speed, or move through a defined position profile.

For production equipment, these capabilities can help coordinate several machine operations, reduce inconsistent movement, and support repeatable production cycles. The actual precision depends on the drive, feedback configuration, mechanical transmission, control software, and rigidity of the complete machine.

4.2 Absolute Encoder Feedback

The RG1 configuration uses a 20-bit single-turn and 12-bit multi-turn absolute encoder with a DRIVE-CLiQ interface. The encoder provides position information to a compatible drive, allowing the system to determine the motor’s position and regulate its movement.

Absolute feedback can be valuable in positioning applications where the controller needs reliable position information across a defined operating range. It can also simplify certain machine-control arrangements compared with systems that rely solely on incremental position counting.

The encoder interface must match the drive and connection system. When replacing a motor, the feedback interface and encoder configuration should be checked as carefully as the power rating.

4.3 Natural Cooling

Natural cooling allows heat to dissipate through the motor housing and surrounding air. This can simplify machine integration because the motor does not depend on a dedicated external fan as its primary cooling method.

However, natural cooling does not eliminate thermal limits. The motor must have adequate ventilation and must be operated within the permitted ambient temperature and duty-cycle conditions. Sustained high torque, repeated acceleration, and restricted airflow can increase winding temperature.

4.4 Smooth Shaft Design

The specified smooth shaft, with tolerance N, is intended for a compatible coupling or other suitable mechanical connection. A smooth shaft can be useful in systems designed around friction-fit or clamping-style couplings.

The shaft diameter, extension, permissible radial and axial loading, and coupling arrangement must be confirmed from the exact mechanical drawing. An incorrectly sized or poorly aligned coupling can introduce vibration, bearing load, and premature mechanical wear.

4.5 No Integrated Holding Brake

The RG1 version is specified without a holding brake. This can be suitable for horizontal axes or other mechanisms where a separate holding function is not required.

For vertical axes, gravity-loaded mechanisms, or applications where the axis must remain stationary after the drive is disabled, the machine design must provide an appropriate means of retaining the load. The absence of a brake should be treated as a key configuration difference when comparing replacement models.

5. Main Applications

5.1 CNC Machine Tools and Machining Equipment

The motor can be considered for compatible machine-tool axes, positioning systems, and automated machining equipment. Servo control allows the drive to regulate movement according to the required speed and position profile.

The 3.8 kW optimum-power rating and 3,000 rpm operating point provide useful selection references. The final choice should be based on the axis’s torque demand, acceleration, reflected inertia, mechanical transmission, and required cycle time.

5.2 Packaging and Filling Machinery

Packaging machines commonly use servo motors for product feeding, indexing, cutting, sealing, and transfer operations. These functions often require consistent speed regulation and coordinated movement between multiple axes.

The absolute encoder can support position-based motion control when used with a compatible drive. The motor must still be sized for the actual load and production cycle, including acceleration peaks and repeated stops.

5.3 Automated Assembly Lines

Automated assembly equipment may need to position components, operate transfer mechanisms, control feed axes, or synchronize multiple stages of a production process.

The motor can be evaluated for these applications where its speed, torque, feedback interface, and mechanical configuration meet the requirements. System performance depends on the complete motion-control arrangement rather than the motor alone.

5.4 Printing and Converting Equipment

Printing, labeling, and converting machinery often requires coordinated roller motion, controlled material feeding, accurate cutting, and repeatable indexing.

A servo motor with absolute feedback can support these functions when its operating characteristics match the application’s demands. The controller and drive must be configured for the required synchronization and motion profile.

5.5 Material Handling and Positioning Systems

The motor can be considered for transfer mechanisms, indexing tables, feeders, positioning stages, and other automated material-handling equipment.

The smooth shaft can be suitable for compatible couplings, while the feedback system supports controlled movement. Where the application carries a vertical or gravity-loaded mass, the lack of an integrated holding brake must be addressed in the machine design.

5.6 Industrial Production Machinery

In automated production systems, servo motors can operate feed axes, adjustment mechanisms, transfer units, and other components that require controlled movement.

The 1FK7 family offers different configurations that can be evaluated according to motor size, feedback requirements, and the intended drive architecture. Correct selection requires matching the motor to the load, operating cycle, and installation environment.

6. Product Advantages

6.1 Strong Performance for Compact Industrial Machinery

The 3.8 kW optimum-power rating provides a useful reference for applications requiring a compact servo motor with a 3,000 rpm operating point. Its frame design can help reduce unnecessary installation space while maintaining the performance needed for many industrial motion-control tasks.

The motor’s suitability depends on the actual operating point. Power, torque, speed, duty cycle, and cooling conditions must be assessed together rather than treating the nominal power figure as the only selection criterion.

6.2 Absolute Position Feedback

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

This is useful in applications that need position-aware control and repeatable movement. The drive must support the encoder configuration, and the feedback wiring and parameters must be correctly configured.

6.3 Stable Speed and Torque Control

When operated with a suitable servo drive, the motor can deliver controlled torque and follow commanded speed profiles. This supports applications that require frequent acceleration, deceleration, indexing, and synchronized movement.

Stable operation depends on correct motor sizing, drive selection, feedback compatibility, and appropriate control tuning. Mechanical vibration and excessive load inertia can limit the performance of even a correctly rated motor.

6.4 Natural Cooling

Natural cooling simplifies the cooling arrangement and avoids dependence on a dedicated external cooling fan as the primary heat-removal method.

The motor still requires suitable ventilation and must remain within its thermal limits. Machine designers should account for ambient temperature, duty cycle, and the amount of heat that can be dissipated from the installed motor.

6.5 IP65 Protection

The IP65 protection rating is useful for many industrial environments where dust protection and resistance to water jets are required.

It should not be interpreted as approval for immersion, unrestricted high-pressure cleaning, or every chemical environment. The suitability of the motor depends on the actual installation conditions and applicable protection requirements.

6.6 Rotatable Power Connector

The rotatable power connector can provide greater flexibility during installation. This can help route cables around machine frames, guards, and other components.

Correct cable routing remains essential. Excessive bending, pulling, twisting, or interference with moving machinery can damage cables or connectors and lead to faults.

6.7 Smooth Shaft for Compatible Couplings

The smooth shaft design can be useful when the machine uses a compatible clamping or friction-fit coupling.

The coupling must match the exact shaft diameter and extension. Alignment and permissible shaft loads must also be checked to prevent unnecessary stress on the motor bearings.

6.8 Clear Configuration for Drive-System Integration

The model is associated with the 1FK7 servo-motor family for SINAMICS S120 Combi systems. This makes it a candidate for applications designed around a compatible drive architecture.

The complete configuration must still be verified. Drive voltage, current, feedback interface, motor parameters, and connection requirements all affect whether a particular motor is suitable.

7. Five Related Models in the Same Series

The following models are useful candidates for comparison within the 1FK7100-2AF71 family. The first four are closely related configurations with similar motor ratings but different feedback or protection details. The final model is included as a related geared-motor configuration for applications where a gearbox may be appropriate.

The ratings shown for the related motors are family-level reference values where applicable. The exact suffix must be checked before procurement.

7.1 Comparison and Selection Notes

1FK7100-2AF71-1CG1 is worth evaluating when the application calls for a higher-resolution absolute encoder configuration. The drive interface, encoder specification, and wiring must be compatible with the machine.

1FK7100-2AF71-1RG2 is a close alternative to the RG1 configuration where the drive-end flange protection requirements differ. The exact environmental requirements should be reviewed before selecting between the two.

1FK7100-2AF71-1PH2 provides a different feedback configuration and includes a holding brake. It may be relevant for applications requiring a brake, but it should not be treated as electrically interchangeable without confirming the drive and feedback arrangements.

1FK7100-2AF71-1CH1 is a geared-motor configuration. Its overall weight and dimensions include the gearbox and therefore differ substantially from those of the standalone motor. Gear ratio, output torque, output speed, and mounting arrangement must be checked for the specific configuration.

The RG1 and RG2 suffixes should not be treated as interchangeable solely because the model numbers are similar. Their protection details and the machine’s environmental requirements should be checked before making a final selection.

8. Five Other Siemens Servo-Motor Models to Consider

The following models broaden the selection beyond the exact 1FK7100 configuration. They can be used as candidates for evaluating a different frame size or another servo-motor family. Exact ratings depend on the complete model number.

8.1 How to Evaluate These Alternatives

1FK7060-2AF71-1CG1: The smaller shaft-height frame may be useful where installation space is limited. Its torque capacity differs from that of the 1FK7100, so the load and acceleration requirements must be recalculated before considering it as a replacement.

1FK7080-5AF71-1AG0: This model can be considered for a more compact installation where the motor’s exact rating and feedback configuration match the application. The full suffix should be verified before ordering.

1FK7083-5AF71-1AG0: This is another 1FK7 family option worth evaluating for compatible automation equipment. The shaft, mounting flange, rated torque, and feedback configuration must be compared against the installed motor.

1FK7100-2AF71-1CG1: This is the closest comparison in the table to the target model because it retains the same basic motor family and reference operating point while changing the encoder configuration.

1FT6086-8AH71-3EG1: This is a different motor-family option. It may be considered where the machine design supports the alternative motor, but it should not be assumed to be a drop-in replacement. Electrical, mechanical, feedback, and drive compatibility all need to be established.

For the models whose exact ratings are not listed, the appropriate approach is to obtain the complete product specification before comparing performance or price. Estimating rated torque, dimensions, or weight from a similar-looking part number can lead to incorrect selection.

9. Installation and Maintenance Recommendations

9.1 Verify the Complete Ordering Code

Record the complete motor model number and compare it with the existing motor’s nameplate. The final characters can identify important differences in encoder type, shaft configuration, brake equipment, and protection rating.

9.2 Check the Servo Drive

Confirm that the installed drive supports the motor’s electrical characteristics and DRIVE-CLiQ feedback interface. Verify the correct motor parameters, drive settings, feedback cable, and connector arrangement before commissioning.

9.3 Confirm Mechanical Compatibility

Check the mounting flange, shaft height, shaft diameter, shaft extension, bolt-hole pattern, and overall length against the mechanical drawing. Leave sufficient clearance for connectors and cable routing.

9.4 Evaluate Load Inertia and Torque Requirements

Calculate the required continuous torque, peak torque, acceleration, deceleration, and reflected load inertia. The motor should be selected for the complete operating cycle, not simply the nominal power rating.

9.5 Plan for the Absence of a Holding Brake

Because the RG1 configuration does not include an integrated holding brake, verify whether the machine needs an external brake or another means of retaining the load when power is removed. This is particularly important for vertical axes and mechanisms affected by gravity.

9.6 Maintain Proper Cooling

Provide sufficient airflow around the motor and avoid enclosing it in a way that traps excessive heat. Check the ambient temperature and duty cycle against the motor’s specified operating limits.

9.7 Inspect Connectors and Mechanical Couplings

During scheduled maintenance, inspect the power connector, feedback cable, shaft coupling, mounting bolts, and nearby mechanical components. Cable damage, misalignment, and loosened fasteners can cause faults or reduce service life.

10. Product Summary

The Siemens 1FK7100-2AF71-1RG1 is a 3.8 kW-class synchronous servo motor in the SIMOTICS S 1FK7 Compact family. It is specified for a 3,000 rpm operating point, 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.

Its main strengths are controlled motion capability, absolute position feedback, a compact industrial design, a rotatable power connector, and a smooth shaft suitable for compatible couplings. The absence of an integrated holding brake is an important consideration when selecting it for vertical or gravity-loaded applications.

For procurement or replacement, the most important checks are the complete ordering code, drive compatibility, encoder interface, shaft dimensions, mounting arrangement, environmental requirements, and the exact weight and overall dimensions. Related 1FK7 models can offer different feedback, brake, or protection configurations, but they should only be substituted after their electrical and mechanical compatibility has been confirmed.