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Kollmorgen AKM52G-ANC2EJN
Overview:
The AKM52G-ANC2EJN is a frameless (slotless) brushless servo motor from Kollmorgen’s AKM product family, designed for direct integration into the mechanical structure of the machine (no bearing housing, no shaft). The model code decodes as: AKM (AKM Series) + 52 (52 mm outer diameter) + G (slotless/frameless variant) + A (with holding brake) + N (standard winding) + C2 (EnDat 2.2 encoder, 128 sine/cosine periods) + E (electrical connector) + J (connector style) + N (natural/standard configuration). This motor is engineered for applications where zero cogging, smooth torque, and compact radial integration are critical.
Detailed content
Key Specifications:
| Parameter | Value |
|---|---|
| Outer Diameter | 52 mm (2.047 in) |
| Inner Diameter (Bore) | 25 mm (customizable) |
| Stack Length | Approximately 30 mm (varies by winding) |
| Continuous Torque | 0.55 Nm (typical at 25°C) |
| Peak Torque | 1.65 Nm (10 seconds) |
| Max Speed | 8,000 RPM (typical) |
| Winding Type | Low-inductance, high-torque-constant |
| Encoder Type | EnDat 2.2, 128 sine/cosine periods (512 counts/rev) |
| Holding Brake | Yes — spring-applied, electrically released (24 VDC) |
| Connector Type | M23, 12-pin (EJN variant) |
| Insulation Class | Class H (180°C) |
| Weight | Approximately 0.18 kg |
| Operating Temperature | -10°C to +80°C (winding) |
Material Composition:
- Stator: Epoxy-bonded lamination stack (silicon steel, 0.2 mm thickness)
- Rotor: Neodymium-Iron-Boron (NdFeB) permanent magnets, N42SH grade, with titanium retention sleeve
- Housing/Structure: Non-magnetic stainless steel 303 for magnetic shielding
- Brake: Spring-loaded friction disc, copper-sintered friction material
- Encoder Disk: Glass substrate with chromium pattern, hermetically sealed
Structural Features:
- Slotless design — zero cogging torque, ultra-smooth motion
- Frameless format — motor is pressed/bonded directly into customer mechanical structure
- No shaft, no bearings, no housing — all mechanical support from host machine
- Radial magnetic circuit — optimized for direct-drive rotary applications
- M23 connector with keyed polarization for error-proof connection
Working Principle:
The AKM52G uses a slotless brushless DC architecture. The stator contains a distributed winding that produces a sinusoidal back-EMF. The drive commutates the three-phase winding based on rotor position feedback from the EnDat 2.2 encoder. Since there are no stator slots, there is zero detent/cogging torque — the motor produces perfectly smooth torque from standstill to full speed. The holding brake uses a spring-loaded mechanism that is mechanically engaged (locked) when de-energized and electrically released (unlocked) when 24 VDC is applied to the brake coil.
Advantages:
- Zero cogging torque — eliminates speed ripple, critical for precision positioning and scanning applications
- Frameless design — eliminates coupling losses, reduces overall system inertia
- High torque-to-inertia ratio — fast acceleration/deceleration
- EnDat 2.2 encoder — high resolution, absolute position on power-up, noise-immune
- Integrated holding brake — holds position without power, no external brake needed
Applicable Industries:
Semiconductor wafer handling, optical scanning and gimbals, medical imaging (CT/MRI gantries), antenna positioning, precision turrets, robotic joints, space mechanisms.
Installation Requirements:
- Press-fit or bond the motor stator into the machine structure with an interference fit of 0.02–0.05 mm
- The customer provides all mechanical bearings and shaft support
- Align encoder coupling to within 0.05 mm TIR
- Brake power supply: 24 VDC ±10%, minimum 200 mA
- Ensure the mechanical structure provides adequate thermal path for stator heat dissipation
Usage Precautions:
- Never run the motor without mechanical support — the frameless stator has no structural integrity on its own
- Do not exceed peak torque for more than 10 seconds continuously — thermal damage to windings will occur
- The holding brake must be released before rotating the motor — running with brake engaged will damage the brake disc
- Store in dry environment — the EnDat encoder is sensitive to moisture ingress
