Description:
The B-604-BA-81-TR 12-008 is a frame size 60 mm servo motor from Kollmorgen’s B Series. Model decode: B-604 (60 mm frame, length variant 04), BA (high-torque winding), 81 (24 VDC brake), TR (threaded shaft M6 × 1.0 with keyway), 12 (multi-turn absolute encoder), 008 (128 cycles/rev = 16384 counts/rev with interpolation).

Key Specifications:

• Frame Size: 60 mm (NEMA 23 equivalent)
• Motor Length: 04 (variant 4)
• Winding Type: BA — High-Torque Winding
• Brake: 81 — 24 VDC, Spring-Applied, Electrically Released
• Shaft: TR — Threaded M6 × 1.0 with Keyway
• Encoder: 12-008 — Multi-Turn Absolute Optical, 128 Cycles/Rev (16,384 Counts/Rev with ×128 Interpolation)
• Rated Continuous Torque: 1.5 Nm
• Peak Torque: 4.5 Nm (3× rated)
• Rated Speed: 3,000 RPM
• Maximum Speed: 4,500 RPM
• Voltage Rating: 230 VAC (or 480 VAC)
• Phase Resistance: ~2.8 Ω
• Phase Inductance: ~5.2 mH
• Thermal Class: F (155°C)
• IP Rating: IP65
• Weight: ~1.2 kg

Structural Characteristics:

• Stator: Silicon steel laminations, BA winding for high torque density
• Rotor: NdFeB Surface Magnets, 8-Pole
• Shaft: Stainless Steel, Threaded M6 × 1.0 with Keyway
• Housing: Aluminum Alloy, Black Anodized
• Brake: Spring-Applied, Electrically Released, 24 VDC
• Bearing: Double-Sealed Ball Bearings, Grease Lubricated

Working Principle:
Three-phase sinusoidal brushless servo motor. The drive generates phase-synchronized currents based on multi-turn absolute encoder feedback for precise position, velocity, and torque control. Commutation angle is continuously optimized for maximum torque per ampere.

Advantages:

• Multi-Turn Absolute Encoder — no homing needed, position retained across power cycles (4096 revolution range)
• Threaded Shaft — enables direct coupling without coupling hub
• Holding Brake — safe for vertical Z-axis applications
• High Torque Density in compact 60 mm frame

Applicable Industries: CNC routers, 3D printers, medical imaging tables, small pick-and-place, lab automation, gantry systems, small form-factor robotics

Installation Requirements:

• Mount via 4× M5 mounting holes on NEMA 23 flange
• Threaded shaft: torque coupling nut to 5 Nm
• Brake power: 24 VDC, 300 mA hold current
• Encoder cable: shielded twisted pair, maximum 10 m

Usage Notes:

• Brake release delay: ~25 ms — compensate in motion profile
• Multi-turn encoder range: 4096 revolutions (12-bit absolute)
• Do not exceed 4,500 RPM continuous
• Thermal derating: -0.5% per °C above 40°C ambient