1FK7042-5AF71-1EG3-2 is a compact permanent magnet synchronous servo motor from Siemens SIMOTICS S series, designed for high-performance automation and motion control systems, and fully compatible with the SINAMICS S120 drive system.
| Modellsegment | Beschreibung |
| 1FK7 | Motor series: 1FK7 compact permanent magnet synchronous servo motor, natural cooling |
| 42 | Motor size: shaft height 42 mm, corresponding to 3 Nm rated torque class |
| 5AF71 | Design and specification: 5AF = standard design; 71 = mounting dimensions and cooling method (natural cooling) |
| 1EG3 | Encoder and options: E = encoder type; G3 = specific encoder configuration (with DRIVE-CLiQ interface) |
| 2 | Additional feature: usually indicates electromagnetic brake to prevent shaft movement during power loss |
- Technische Kernparameter
| Artikel | Spezifikation |
| Rated torque | 3.0 Nm (100K temperature class) |
| Nennleistung | 0.82 KW (1.1 HP) |
| Nenngeschwindigkeit | 3000 U/min |
| Nennstrom | 1.95 A |
| Kühlmethode | Natural cooling (no external fan required) |
| Montageart | IM B5 (IM V1, IM V3) – flange mounting |
| Schutzklasse | Standard IP65 (IP64 at shaft end); higher protection optional |
| Encodertyp | Absolutwertgeber (identified by 1EG3), with DRIVE-CLiQ interface |
| Connector feature | Power/signal connectors rotatable through 270° for easy wiring |
| Rotor inertia | Low-inertia design for improved dynamic response |
| Gewicht | Ca. 4.9–5.0 kg (without brake) |
| Number of pole pairs | 4 |
- Key Features and Advantages
- High-performance permanent magnet design: Uses rare-earth permanent magnets for high power density, high efficiency and low energy consumption.
- High overload capability: Withstands short-term overload above 3x rated torque to adapt to dynamic load changes.
- Precise control: Achieves high-precision positioning and speed control with SINAMICS S120 drives.
- Bremsfunktion: Suffix “2” means electromagnetic brake, suitable for vertical axes or gravity-loaded applications to prevent dropping when powered off.
- Flexible Installation: IM B5 flange mounting, rotatable connectors, adaptable to various mechanical layouts.
- Reliability and durability: Schutzart IP65, geeignet für raue Industrieumgebungen, long bearing life.
- Diagnostic function: Provides comprehensive motor status monitoring and diagnostics via DRIVE-CLiQ.
- Typische Anwendungen
- Automatisierte Produktionslinien: Precise control of conveyors, positioning stages, assembly machinery.
- Robotics: Joint drives, end-effector positioning, especially applications requiring position retention at power loss.
- Verpackungsmaschinen: High-speed, precise control of paper feeding, bag making, Versiegelung, usw.
- Printing equipment: Register accuracy control, web tension regulation.
- Werkzeugmaschinen: Feed and spindle drives for CNC milling machines, lathes.
- Semiconductor equipment: Wafer handling, positioning platforms requiring high cleanliness and precision.
- Medizinische Geräte: Precise motion control for diagnostic and therapeutic devices.
- Model Comparison within the Same Series
| Modell | Hauptunterschied | Anwendung |
| 1FK7042-5AF71-1EG0 | Without brake | Horizontal axis, non-gravity load |
| 1FK7042-5AF71-1EG3 | Mit Bremse (this model) | Vertical axis, gravity load, position retention required at power loss |
| 1FK7042-5AF71-1EG5 | Different encoder resolution | Applications requiring higher positioning accuracy |
| 1FK7042-5AF71-1GG5 | Basic absolute encoder (32 P/REV) | Cost-sensitive applications with moderate accuracy requirements |
| 1FK7042-5AF71-1FA0 | Absolutwertgeber (2048 P/REV) | High-precision positioning applications |
- Drive Compatibility and Replacement Solutions
- Recommended drive: SINAMICS S120 series, perfectly matched to 1FK7 series characteristics.
- Alternative models:
Siemens replacement: 1FT7042 series (mechanically compatible, ähnliche Leistung)
Third-party alternatives: Schneider LXM series, ABB ACS series, Mitsubishi MR-J series (observe parameter matching)
- Upgrade path: Für höhere Leistung, consider 1FK7060 (5 Nm) or 1FK7080 (8 Nm).
- Installations- und Wartungsrichtlinien
- Pre-installation checks:
Confirm compatibility between motor and drive system.
Inspect motor appearance and shaft condition.
Verify encoder type and interface.
- Installation precautions:
Ensure flatness during flange mounting to avoid eccentric load.
Rotate connectors to optimal wiring position (max. 270°).
Correctly connect brake wiring to the brake control terminal of the drive.
- Maintenance recommendations:
Regularly check motor temperature (normal operating temperature < 85 °C).
Keep motor clean to avoid dust buildup affecting heat dissipation.
Periodically verify brake operation for reliable holding when de-energized.
Protect encoder cables from strong electromagnetic interference.
1FK7042-5AF71-1EG3-2 is a 3 Nm compact permanent magnet synchronous servo motor from Siemens SIMOTICS S series, equipped with absolute encoder and brake, naturally cooled. It is ideal for industrial automation applications requiring high-precision positioning and position retention at power loss.
With low inertia and high overload capability, it performs excellently in high dynamic response applications, and achieves outstanding motion control performance with the SINAMICS S120 drive system.
Siemens 1FK7042 Series Servo Motor: Complete Coding System and Cross-Brand Alternatives
- Full Model Naming Convention
Each segment of 1FK7042-XXXXX-XXXX-X has a clear meaning that defines core properties and configuration:
| Segment | Code | Beschreibung |
| 1FK7 | Fixed prefix | Siemens SIMOTICS S compact PMSM, natural cooling |
| 42 | Größencode | Shaft height 42 mm, 3 Nm rated torque; 04 = shaft height, 2 = length class |
| XX | Design type | 2A = standard compact |
| 3B = high inertia | ||
| 5A = compact (510V–720V) | ||
| 2C = high dynamic | ||
| F71 | Kühlung & Montage | F = standard flange; 7 = with connector; 1 = natural cooling |
| 1XX | Encodertyp | 1E = absolute (DRIVE-CLiQ) |
| 1F = incremental | ||
| 1P = resolver | ||
| 1Q = absolute 20-bit single-turn | ||
| 1R = absolute 24-bit single-turn + 12-bit multi-turn | ||
| X | Additional feature | 0 = no brake |
| 2 = with electromagnetic brake | ||
| 3 = special protection | ||
| 5 = with incremental encoder | ||
| X | Interface/accuracy | G3 = DRIVE-CLiQ, high resolution |
| A0 = standard accuracy | ||
| H2 = with mechanical brake | ||
| U0 = incremental encoder (±1 pulse accuracy) |
- Complete 1FK7042 Model List (by Configuration)
2.1 Standard Compact (2A/5A) Basic Configurations
| Vollständiges Modell | Core Configuration | Anwendung |
| 1FK7042-2AF71-1AG0 | 3Nm, 3000U/min, 0.82KW, incremental encoder, keine Bremse | Horizontal drive, general positioning accuracy |
| 1FK7042-2AF71-1QG0 | 3Nm, 3000U/min, 0.82KW, 20-bit single-turn absolute encoder, keine Bremse | High-precision positioning, position memory at power loss |
| 1FK7042-2AF71-1RB0 | 3Nm, 3000U/min, 0.82KW, 24-bit single-turn +12-bit multi-turn absolute encoder, keine Bremse | Multi-axis linkage, komplexe Bewegungssteuerung |
| 1FK7042-5AF71-1EG3-2 | 3Nm, 3000U/min, 0.82KW, absolute encoder (DRIVE-CLiQ), with brake | Vertical axis, gravity load, anti-drop at power loss |
| 1FK7042-5AF71-1FH3 | 3Nm, 3000U/min, 0.82KW, incremental encoder, with brake | High-speed reciprocating motion, high dynamic response |
| 1FK7042-2AF71-1PA0 | 3Nm, 3000U/min, 0.82KW, resolver, keine Bremse | Harsh EMI environment, high anti-interference requirement |
| 1FK7042-2AF71-1CB0 | 3Nm, 3000U/min, 0.82KW, absolute encoder, special protection | Dust/moist environment, IP67 |
2.2 High-Inertia / High-Dynamic Special Configurations
| Vollständiges Modell | Core Configuration | Anwendung |
| 1FK7042-3BK71-1QH2 | 3Nm, 3000U/min, 0.9KW, high inertia, absolute encoder, with brake | Large inertia matching, smooth start/stop |
| 1FK7042-2AC71-1QA0 | 3Nm, 6000U/min, 1.8KW, high dynamic, absolute encoder, keine Bremse | High-speed positioning, schnelle Reaktion |
| 1FK7042-2AK74-1TH0 | 3Nm, 6000U/min, 0.9KW, kompakt, resolver, with brake | High-speed motion, anti-interference required |
- Mainstream Brand Alternatives (3 Nm Class)
3.1 Siemens Internal Replacements
| Original | Alternative | Kompatibilität |
| 1FK7042-5AF71-1EG3-2 | 1FT7042-5AF71-1CH1-Z N05 | Fully mechanical compatible, same performance, same encoder interface |
| 1FK7042-2AF71-1QG0 | 1FK7042-5AF71-1QH0 | Optimized voltage range, otherwise identical |
| 1FK7042-2AF71-1PA0 | 1FK7042-5AF71-1PH0 | Upgraded resolver interface, improved protection |
3.2 Schneider Electric
| Alternative | Bestell-Nr. | Wichtige Matching-Parameter |
| BCH2MF0733CA1C | 140S-M-0733 | 3Nm, 3000U/min, 0.85KW, absolute encoder, with brake |
| LXM32AD18M2+BSH0701P01A2A | 9020-0701 | Drive+motor set, 3Nm, 3000U/min, compatible with SINAMICS environment |
3.3 ABB
| Alternative | Bestell-Nr. | Wichtige Matching-Parameter |
| MotiFlex e180+M3AA08060HB | 3ABD00012600 | 3Nm, 3000U/min, 0.82KW, absolute encoder, with brake |
| ACS880-01-040A-5+MQM0804-0300 | 3AXD50000038924 | Drive+motor set, fits 1FK7 mounting dimensions |
3.4 Mitsubishi
| Alternative | Bestell-Nr. | Wichtige Matching-Parameter |
| MR-J4-350B+HF-KP43 | MR-J4-350B+HF-KP43B | 3.5Nm (compatible with 3Nm), 3000U/min, absolute encoder, with brake |
| MR-J5-350B+HF-KP43B | MR-J5-350B+HF-KP43B | New generation, optimized communication, ~15% performance boost |
3.5 OMRON
| Alternative | Bestell-Nr. | Wichtige Matching-Parameter |
| R88M-G30030H-S2-Z | R88M-G30030H-S2-Z | 3Nm, 3000U/min, 0.8KW, absolute encoder, with brake |
| 1S Series + R88D-1SN03H-ECT | 1S030-30CB2-D + R88D-1SN03H-ECT | Integrated safety, SIL3 certified, for harsh industrial environments |
- Key Guidelines for Replacement Selection
- Parameter matching priority:
Rated torque (3 Nm) > Nenngeschwindigkeit (3000 U/min) > Leistung (0.82 KW) > Rotor inertia > Schutzklasse
Encoder type must match the system (absolute / inkrementell / resolver)
Bremse (Suffix 2) is mandatory for vertical axes.
- Mechanical compatibility:
Match flange (IM B5), Wellendurchmesser, keyway to original equipment.
Connectors rotatable 270° for wiring convenience.
Brake wiring must match drive brake control terminals.
- Drive compatibility:
Siemens SINAMICS S120 works natively with 1FK7/1FT7.
Third-party drives must support the encoder interface (DRIVE-CLiQ / SSI / inkrementell).
Same-brand drive-motor combinations are recommended to minimize issues.
The 1FK7042 series is the core 3 Nm torque class product in the Siemens SIMOTICS S family.
With various encoder, brake and protection configurations, it covers standard industrial to harsh environment applications.
When selecting replacements, prioritize matching torque, Geschwindigkeit, encoder type and mounting dimensions, while ensuring drive compatibility and long-term supply stability.
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