Kollmorgen 6SM Series Servo Motors

Technical Dossier

Product Details And Specifications

Kollmorgen 6SM Series: Comprehensive Module Range and Technical Overview

The Kollmorgen 6SM series represents a mature line of brushless AC servo motors engineered for high-precision motion control in demanding industrial environments. Deployed extensively across chemical processing plants, oil refineries, nuclear facility auxiliary systems, steel mills, and paper manufacturing lines, the 6SM series established a benchmark for torque density and thermal stability in the 1990s and 2000s. These motors are characterized by their permanent magnet rotor construction, resolver-based feedback, and compatibility with Kollmorgen's S200, S600, and AKD servo drive platforms. The installed base of 6SM motors in global heavy industry remains substantial, making reliable spare parts sourcing a critical operational requirement for maintenance engineers worldwide.

The Evolution of 6SM Architecture

The 6SM series was introduced by Kollmorgen (then operating under the Danaher Motion umbrella) as a successor to earlier M-Series and BH-Series servo motors. The original 6SM design utilized a 6-pole stator configuration with sinusoidal back-EMF, optimized for smooth velocity control at low speeds — a requirement driven by machine tool and semiconductor handling applications of the era.

Early 6SM variants shipped with single-turn resolvers as standard feedback devices. Mid-generation revisions introduced multi-turn absolute encoder options (suffix -E) and enhanced IP65 sealing (suffix -G denoting grease-purged shaft seal). The thermal class was upgraded from Class F to Class H in later production runs, extending continuous duty ratings in high-ambient installations.

Compatibility note: 6SM motors with resolver feedback are directly interchangeable with S200 and S600 drives using the standard RES feedback cable. Integration with the AKD platform requires a resolver-to-digital converter module or substitution with an AKM-series motor. Engineers maintaining legacy 6SM installations must verify drive firmware compatibility when replacing motors, as AKD firmware versions prior to M_01-10-00-000 do not support 6SM resolver parameters natively.

The 6SM series entered end-of-life status in the mid-2010s. Kollmorgen's current AKM and AKM2G series are the designated modern replacements, offering higher power density and native SFD3/EnDat 2.2 feedback. However, direct mechanical and electrical substitution is not always feasible without drive reconfiguration, making original 6SM spare units the preferred solution for brownfield maintenance.

6SM Full Catalog & Functionalities (SKU List)

The following SKUs represent verified models within the Kollmorgen 6SM series. Models are organized by frame size and winding configuration. All units are brushless AC servo motors with permanent magnet rotors unless otherwise noted.

Frame Size 3 (Low Inertia, Compact)

• 6SM31S-3000: Frame 3, standard winding, 3000 RPM rated speed, resolver feedback, single-ended shaft.
• 6SM31S-6000: Frame 3, standard winding, 6000 RPM rated speed, resolver feedback, high-speed spindle variant.
• 6SM32S-3000: Frame 3, medium torque winding, 3000 RPM, resolver, standard IP54 enclosure.
• 6SM33S-3000: Frame 3, high torque winding, 3000 RPM, resolver, suitable for indexing applications.

Frame Size 5 (Mid-Range Torque)

• 6SM51S-3000: Frame 5, standard winding, 3000 RPM, resolver, general-purpose servo axis.
• 6SM52S-3000: Frame 5, medium torque, 3000 RPM, resolver, common in CNC rotary axis applications.
• 6SM53S-3000: Frame 5, high torque winding, 3000 RPM, resolver, used in heavy-duty feed axis drives.
• 6SM53S-6000: Frame 5, high torque winding, 6000 RPM, resolver, extended speed range variant.

Frame Size 7 (High Torque)

• 6SM71S-3000: Frame 7, standard winding, 3000 RPM, resolver, primary axis motor for large machining centers.
• 6SM72S-3000: Frame 7, medium torque, 3000 RPM, resolver, industrial robot joint actuator.
• 6SM73S-3000: Frame 7, high torque winding, 3000 RPM, resolver, heavy press and forming machine axis.

Frame Size 3, -G Sealed Variants (IP65 Shaft Seal)

• 6SM31S-3000-G: Frame 3, 3000 RPM, resolver, grease-purged IP65 shaft seal, wash-down rated.
• 6SM33S-3000-G: Frame 3, high torque, 3000 RPM, resolver, IP65 shaft seal, food & beverage line use.
• 6SM37S-3000-G: Frame 3, extended torque winding, 3000 RPM, resolver, IP65 shaft seal.
• 6SM37S-6000-G: Frame 3, extended torque winding, 6000 RPM, resolver, IP65 shaft seal — this listing. Deployed in high-speed precision axes requiring environmental sealing against coolant and particulate ingress.
• 6SM53S-3000-G: Frame 5, high torque, 3000 RPM, resolver, IP65 shaft seal, chemical plant actuator.

Sourcing Hard-to-Find & Obsolete 6SM Series Parts

The Kollmorgen 6SM series reached official end-of-production status, and OEM new-stock availability is no longer guaranteed through standard distribution channels. DriveKNMS maintains a dedicated inventory program for obsolete and hard-to-find servo motor units, with specific focus on the 6SM series due to its continued presence in operating industrial facilities.

DriveKNMS sources 6SM units through three primary channels: decommissioned equipment recovery from plant shutdowns, authorized surplus dealer networks, and direct acquisition from maintenance stockrooms. Each unit is catalogued by full part number including winding suffix, speed rating, and sealing designation to ensure exact-match fulfillment. For models with multiple feedback variants (resolver vs. encoder), DriveKNMS verifies the feedback type prior to shipment to prevent drive incompatibility on installation.

Quality Control for the 6SM Range

All 6SM series units processed by DriveKNMS undergo a structured inspection and functional test protocol prior to dispatch. The test sequence addresses the specific failure modes documented in the 6SM series field service history:

Resolver integrity check: Excitation voltage applied at 7 Vrms / 10 kHz. Sin/cos output amplitude and phase angle verified against OEM specification (±1% amplitude balance, <1° phase error). Units with resolver degradation are flagged for rewind or replacement before shipment.

Winding resistance and insulation test: Phase-to-phase resistance measured and compared against frame-size reference values. Insulation resistance tested at 500 VDC megohm; minimum acceptance threshold 100 MΩ.

Bearing inspection and relubrication: Bearings rotated under load simulation. Units with audible defects or elevated drag torque receive bearing replacement using OEM-equivalent SKF or FAG units. Grease-sealed variants (suffix -G) receive fresh grease charge per Kollmorgen service bulletin.

Back-EMF verification: Motor driven at reference speed on test stand; back-EMF waveform captured and compared to OEM sinusoidal profile. Harmonic distortion >3% THD results in rejection.

Dimensional inspection: Shaft runout, flange flatness, and keyway dimensions verified to drawing tolerances. Critical for direct-coupled applications where mechanical runout causes premature bearing failure in the driven load.