SIEMENS 1FK7103-5AC71-1KG5 Synchronous Servo Motor | Replacement, Equivalent & Selection Guide
The SIEMENS 1FK7103-5AC71-1KG5 is a high-performance synchronous servo motor from the SIMOTICS S-1FK7 series, engineered for precision motion control in demanding industrial automation environments. This page provides full technical specifications, compatible replacement models, selection guidance, and sourcing information to help engineers and procurement teams make confident decisions.
Technical Specifications
- Manufacturer: Siemens AG
- Part Number / SKU: 1FK7103-5AC71-1KG5
- Series: SIMOTICS S-1FK7 (Compact)
- Motor Type: Synchronous Servo Motor (Permanent Magnet)
- Rated Speed: 3000 rpm
- Rated Torque: ~18 Nm (nominal)
- Peak Torque: ~54 Nm
- Rated Power: ~5.5 kW
- Voltage: 3-phase AC, 400 V
- Encoder: Absolute encoder (DRIVE-CLiQ interface)
- Shaft: Smooth shaft with key (1KG5 suffix)
- Cooling: Natural convection (self-cooled)
- Protection Class: IP64
- Weight: ~6.8 kg
- Mounting: Flange mount (IM B5)
- Compatible Drive: SINAMICS S120 / S110
Compatible Replacement & Equivalent Models
When the original 1FK7103-5AC71-1KG5 is unavailable or requires a cost-effective alternative, the following models offer compatible performance characteristics:
- SIEMENS 1FK7100-5AC71-1KG5 — Same frame, slightly lower torque rating; direct mechanical fit
- SIEMENS 1FK7103-5AC71-1AG5 — Incremental encoder variant; requires drive parameter adjustment
- SIEMENS 1FK7103-5AC71-1RG5 — Resolver feedback variant; compatible with older SIMODRIVE drives
- SIEMENS 1FK7105-5AC71-1KG5 — Higher torque next-step model; same mounting interface
- Lenze MCS Series (equivalent frame) — Third-party alternative; verify torque/encoder compatibility before substitution
- Bosch Rexroth MSK100C — Cross-brand equivalent for comparable power class; requires adapter coupling
Note: Always verify encoder type, shaft configuration, and drive compatibility before substituting. Contact our technical team for a validated replacement recommendation.
Why Choose the Original Model
- Guaranteed compatibility with SINAMICS S120 via DRIVE-CLiQ plug-and-play
- Absolute encoder eliminates homing cycles after power loss — critical for safety-critical axes
- Siemens TIA Portal integration with pre-configured motor data sets (MDS)
- Proven reliability in 24/7 continuous-duty industrial environments
- Global spare parts availability and Siemens service network support
Typical Applications
- CNC machine tool spindle and feed axis drives
- Packaging machinery (pick-and-place, sealing, indexing)
- Printing and converting equipment
- Robotic arm joints and gantry systems
- Semiconductor and electronics assembly automation
- Textile and winding machinery
System Compatibility
- Drive Systems: SINAMICS S120 (booksize / chassis), SINAMICS S110
- Controllers: SIMATIC S7-1500, S7-300/400 with PROFINET/PROFIBUS
- Engineering Software: SINAMICS Startdrive (TIA Portal V15+), STARTER
- Communication: DRIVE-CLiQ (encoder/motor data), PROFINET IRT
- Safety Functions: STO, SS1, SLS via SINAMICS Safety Integrated
Selection Guide
Use the following criteria to confirm the 1FK7103-5AC71-1KG5 is the right choice, or to identify the correct variant for your application:
- Torque requirement: Confirm peak and continuous torque against your load profile (duty cycle S1/S3/S6)
- Speed range: Verify rated and maximum speed against your motion profile
- Encoder type: Absolute (1KG5) vs. incremental (1AG5) vs. resolver (1RG5) — choose based on drive and safety requirements
- Shaft type: Smooth with key (standard) vs. plain smooth shaft — confirm coupling interface
- Mounting: IM B5 flange — verify bolt circle and pilot diameter against your gearbox or machine frame
- Ambient conditions: IP64 standard; IP65/67 variants available for washdown environments
- Drive pairing: Match motor power class to SINAMICS S120 power module rating
Quality Assurance & Sourcing
- All units sourced from authorized distributors or verified surplus channels
- Each motor undergoes incoming inspection: visual check, encoder signal verification, and insulation resistance test
- Original Siemens packaging and documentation preserved where available
- Traceability records maintained for serial number, batch, and sourcing channel
- Export compliance reviewed for applicable trade regulations (CN export, EU/US import)
How to Order
- Confirm part number: 1FK7103-5AC71-1KG5
- Specify quantity and required delivery timeline
- Contact us via email or phone for stock confirmation and pricing
- Receive proforma invoice → arrange payment → shipment with tracking
- Post-delivery technical support available via email
Email: support@konmask.com
Phone / WhatsApp: +0086 19859288691
Website: https://konmask.com
Replacement & Compatibility FAQ
Q: Can I use 1FK7103-5AC71-1AG5 as a direct replacement?
A: Mechanically yes — same frame and shaft. However, the incremental encoder requires drive re-parameterization and a homing routine after each power cycle. Not recommended for safety axes without engineering review.
Q: Is this motor compatible with SIMODRIVE 611?
A: No. The 1FK7 with DRIVE-CLiQ encoder is designed for SINAMICS. For SIMODRIVE 611, you need a resolver-feedback variant (suffix 1RG5) and the appropriate motor module.
Q: What is the lead time for new stock?
A: In-stock units ship within 1–3 business days. For new factory orders, standard lead time is 8–14 weeks. Contact us for current availability.
Q: Do you provide a warranty?
A: Yes. All units carry a minimum 12-month warranty against manufacturing defects. Extended warranty options available on request.
Q: Can konmask.com assist with drive and motor commissioning?
A: We provide technical documentation and remote guidance. For on-site commissioning, we can refer you to certified Siemens service partners in your region.
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Contact: support@konmask.com | +0086 19859288691
