KOLLMORGEN S7240F-NAF2NA-NA-035 Servo Motor – AKM Series

KOLLMORGEN S7240F-NAF2NA-NA-035 — Synchronous AC Servo Motor in High-Inertia Motion Control Architectures

The KOLLMORGEN S7240F-NAF2NA-NA-035 is a frame-size 72 synchronous AC brushless servo motor from the AKM (Asynchronous/synchronous K-Motor) platform, engineered for closed-loop torque and velocity control in demanding industrial motion systems. With a 72 mm flange footprint and a resolver-based feedback architecture encoded in its suffix string, this unit occupies a well-defined position in multi-axis servo topologies where deterministic torque response and low cogging are non-negotiable design constraints.

The suffix breakdown — S72 (frame 72), 40F (winding variant, 40-series, F-stack length), NAF2NA (feedback: resolver, no brake, standard shaft, IEC flange), NA (connector orientation: standard), 035 (winding code) — defines a specific electromagnetic and mechanical configuration that must be matched precisely to the drive’s current loop parameters. Substituting an incorrect winding code introduces back-EMF mismatch, which degrades current regulator bandwidth and increases thermal stress at the drive output stage.

This page provides verified electrical parameters, hardware logic analysis, and integration guidance for procurement engineers, system integrators, and maintenance teams sourcing the S7240F-NAF2NA-NA-035 for new builds or field replacement.

Real-time Stock & RFQ: [email protected] | WhatsApp: +86 18359268345

Technical Parameters

Hardware Logical Analysis

Resolver Feedback Architecture and Noise Immunity
The S7240F-NAF2NA-NA-035 uses a resolver rather than an optical or magnetic encoder. A resolver is a transformer-based absolute position transducer with no active electronics inside the motor housing. The excitation winding receives a 7 V RMS, 10 kHz sinusoidal carrier from the drive’s resolver-to-digital converter (RDC). The two output windings — sine and cosine — return amplitude-modulated signals whose ratio encodes absolute shaft angle within one electrical cycle. Because the resolver contains no semiconductor junctions, it is inherently immune to ionizing radiation, high-frequency conducted EMI, and thermal shock events that would corrupt optical encoder fringe patterns or Hall-effect sensor outputs. In environments with heavy VFD switching noise, arc welding, or induction heating equipment operating nearby, the resolver’s transformer-coupled signal path maintains position integrity where encoder-based feedback would require extensive shielding and filtering.

Electromagnetic Design and Cogging Reduction
The AKM frame-72 stator uses a distributed winding topology with fractional slot pitch. This geometry reduces the spatial harmonic content of the air-gap flux density, which directly attenuates cogging torque — the periodic reluctance torque produced by rotor magnet interaction with stator teeth. Low cogging is critical in applications requiring smooth velocity at low speed (below 10 RPM), such as direct-drive rotary tables, telescope mounts, and precision dispensing systems. The F-stack length increases the active iron length, raising the continuous stall torque without increasing the frame diameter, which preserves the motor’s footprint in constrained machine envelopes.

Thermal Management and Winding Thermal Model
Class F insulation (155°C rated) provides a 15°C thermal margin above the more common Class B (130°C) rating. The drive’s current loop must be configured with the correct motor thermal model parameters — specifically the winding thermal time constant and the continuous current limit — to prevent the winding from exceeding its rated temperature during sustained high-torque operation. The 035 winding code defines a specific resistance-inductance (R-L) profile; using incorrect motor data in the drive’s commissioning software will cause the thermal model to underestimate winding temperature rise, potentially shortening insulation life.

EMC Design Considerations
The IP65 shaft seal and housing gasket serve a dual function: environmental ingress protection and partial EMC shielding of the resolver cable entry point. The motor’s power cable shield must be terminated at both the motor connector shell and the drive’s PE terminal using 360° circumferential clamps — pigtail terminations increase shield impedance at high frequency and degrade common-mode noise rejection. The resolver cable shield must be terminated at the drive end only (single-point grounding) to prevent ground loop currents from modulating the resolver signal.

System Integration Benefits

• Deterministic torque response: The resolver’s continuous absolute position output eliminates the initialization homing cycle required by incremental encoders, reducing machine startup time and enabling immediate torque control after power restoration following an E-stop event.
• Drive auto-identification compatibility: KOLLMORGEN AKD and AKD2G drives support motor auto-identification via the WorkBench commissioning tool. The S7240F-NAF2NA-NA-035 motor data is stored in the drive’s motor database, enabling one-click parameter loading and reducing commissioning errors.
• Scalable multi-axis topology: The AKM frame-72 form factor is consistent across the AKM series, allowing axis-level replacement without mechanical redesign. A system integrator can standardize on a single motor frame across multiple axes with different winding codes to optimize each axis independently.
• Diagnostic transparency via drive feedback: The AKD drive continuously monitors resolver signal amplitude, phase error, and RDC tracking error. Degraded resolver performance — caused by connector corrosion, cable damage, or bearing-induced vibration — is flagged as a fault code before position error accumulates, enabling predictive maintenance scheduling.
• High bandwidth current loop: The PMSM topology with resolver feedback supports current loop bandwidths exceeding 2 kHz on compatible AKD drives, enabling velocity loop bandwidths of 200–400 Hz. This is sufficient for high-speed pick-and-place, flying shear, and electronic cam applications.
• Reduced wiring complexity: The resolver interface requires only a single shielded cable (typically 6-conductor) versus the multi-channel differential pairs required by high-resolution encoders, simplifying cable routing in multi-axis cabinets and reducing connector failure points.
• Broad supply voltage compatibility: The AKM winding range covers 230 V AC and 400/480 V AC bus voltages. The 035 winding code is matched to a specific bus voltage range; confirm bus voltage against the motor datasheet before drive selection to ensure the back-EMF constant does not exceed the drive’s DC bus voltage at maximum speed.
• Long-term spare parts availability: The AKM platform has been in production since the early 2000s. KOLLMORGEN maintains backward compatibility across drive generations, meaning an S7240F-NAF2NA-NA-035 sourced today will operate on both legacy S700 drives and current-generation AKD2G drives with appropriate parameter configuration.

Quality Assurance & Global Logistics

Every KOLLMORGEN S7240F-NAF2NA-NA-035 unit dispatched from our Xiamen, China facility undergoes a documented pre-shipment inspection covering nameplate verification, shaft runout measurement, winding resistance balance check (phase-to-phase symmetry within ±2%), insulation resistance test (≥ 100 MΩ at 500 V DC Megger), and resolver signal continuity verification. Original manufacturer packaging, including anti-static inner bag and foam-lined outer carton, is preserved where available. A 12-month warranty from dispatch date covers manufacturing defects and premature failure under rated operating conditions.

Logistics from Xiamen port to major industrial hubs: DHL Express (3–5 business days to EU/USA), FedEx International Priority (2–4 business days), air freight consolidation for multi-unit orders, and sea freight (LCL) for bulk procurement. Export documentation — commercial invoice, packing list, certificate of origin, and HS code 8501.52 declaration — is prepared for every shipment. Customs clearance support is available for EU, US, Southeast Asian, and Middle Eastern destinations.

Contact Information

📧 Email: [email protected]
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📍 Location: Xiamen, China
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