B&R 8MSA4S.R0-31

Technical Specifications:

Functional Features:

• Single-turn absolute encoder provides position within one revolution after power-on (requires reference run for multi-turn)
• High-speed capability up to 8000 rpm
• Ultra-low rotor inertia for fastest dynamic response in the 8MSA family
• Integrated temperature sensor (KTY84)
• Compact form factor for space-constrained installations

Performance Parameters:

• Torque Constant (Kt): 0.10 Nm/A
• Back-EMF Constant (Ke): 10 V/1000 rpm
• Rated Current: 3.8 A
• Peak Current: 11.4 A
• Electrical Time Constant: 2.1 ms
• Mechanical Time Constant: 3.2 ms
• Rated Power: 0.22 kW

Material Composition:

• Stator Laminations: Non-oriented silicon steel (FeSi), 0.2 mm thickness
• Rotor: NdFeB permanent magnets (N35EH grade)
• Housing: Aluminum alloy die-cast (EN AC-46000)
• Shaft: Stainless steel (X20Cr13), ground
• Bearings: Miniature deep groove ball bearings (6800 series), sealed
• Connector: M12 connector, 12-pin, IP67

Structural Features:

• 31 mm square flange with four M4 mounting holes
• Rear-mounted encoder with plastic cap
• Internal fan on drive end
• Single PG9 cable gland
• Keyway shaft, no retention ring groove (due to small size)

Working Principle:
The motor is a permanent magnet synchronous machine. The servo drive generates a three-phase rotating magnetic field in the stator. The NdFeB rotor locks to this field and rotates at synchronous speed. The single-turn absolute encoder outputs Sin/Cos signals for interpolation to high resolution within one revolution. For multi-turn position, the drive must perform a reference run at startup.

Advantages & Highlights:

• Smallest 8MSA motor — 31 mm flange, 0.55 kg
• Ultra-fast dynamics — mechanical time constant of 3.2 ms
• 8000 rpm max speed for high-throughput applications
• Single-turn absolute — no homing needed within one revolution
• Ideal for pick-and-place, labeling, and small robotics

Applicable Industries:

• Semiconductor wafer handling
• Pharmaceutical packaging
• Electronics assembly (SMT feeders)
• Small-scale robotics
• Laboratory automation
• Textile spinning spindles

Installation Requirements:

• Mount with four M4 bolts, torque 1.5 Nm
• Minimum 30 mm clearance around motor body
• Use B&R 8YS-K0055R0.005-0 or equivalent shielded cable
• Ground resistance ≤ 1 Ω
• Ambient temperature: 0°C to +45°C (derate above 40°C)

Usage Precautions:

• Do not exceed 8000 rpm under any condition
• Do not apply radial loads > 50 N
• Encode cable bend radius ≥ 50 mm
• Replace bearings at 8,000 operating hours
• Do not operate in environments with conductive dust