Overview
The CubeMars RI50 KV100 Frameless Inrunner Torque Motor is purpose-built for high-performance robotic applications such as cobot arms, exoskeletons, and lightweight industrial automation systems. Operating at 24V to 48V, it features lower cogging torque for smooth motion, high torque density, and 0.01° high-precision control. Its compact frameless design ensures easy integration into tight spaces, while hand-wound copper coils, curved permanent magnets, and optimized sinusoidal BEMF design deliver powerful dynamics and efficient control.
The RI50 is now available in a heightened version (+3mm rotor) for improved hall sensor detection, ideal for applications requiring high-accuracy feedback. With strong thermal stability, low noise, and support for high-resolution encoders (e.g., Renishaw, Sick), the RI50 meets the demands of professional-grade robotics with precision, modularity, and performance.
Key Features
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Rated Voltage: 24V / 36V / 48V
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Rated Torque: 0.58 Nm / Peak Torque: 1.67 Nm
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Rated Speed: Up to 2600 rpm
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Kv: 100 rpm/V | Kt: 0.120 Nm/A
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High Efficiency & Torque-to-Weight Ratio: 9.24 Nm/kg
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Low Cogging Torque: Smooth motion with minimal vibration
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Frameless, Compact Design: Easy to embed in custom robotic joints
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Working Temp: -20°C to 50°C (Encoder -40°C to 85°C)
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Supports Hall & Precision Encoders (0.01°)
Technical Specifications
General
| Parameter | Value |
|---|---|
| Application | Cobot Arm / Exoskeleton |
| Driving Way | FOC |
| Winding Type | Star |
| Insulation Class | C |
| Phase | 3 |
| Pole Pairs | 7 |
| Operation Temp | -20℃ to 50℃ |
| Insulation Voltage | 500V, 5mA / 2s |
| Insulation Resistance | 500V, 10MΩ |
| Weight | 180.8 g |
| Max Torque/Weight Ratio | 9.24 Nm/kg |
Electrical
| Parameter | Value |
|---|---|
| Rated Voltage (V) | 24 / 36 / 48 |
| No-load Speed (rpm) | 2004 / 3006 / 4008 |
| Rated Speed (rpm) | 1090 / 1860 / 2600 |
| Rated Torque (Nm) | 0.58 |
| Peak Torque (Nm) | 1.67 |
| Rated Current (A) | 4.8 |
| Peak Current (A) | 14.8 |
| Kv (rpm/V) | 100 |
| Kt (Nm/A) | 0.120 |
| Ke (V/krpm) | 11.41 |
| Phase Resistance (mΩ) | 1420 |
| Inductance (μH) | 1500 |
| Inertia (g·cm²) | 22.8 |
| Km (Nm/√W) | 0.1007 |
| Mechanical Time Constant (ms) | 0.22 |
| Electrical Time Constant (ms) | 1.06 |
Rotor & Stator Highlights
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Hand-Wound Stator: Precise winding with excellent copper fill factor for high torque density.
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0.5mm Clearance: Edge gap on stator improves installation ease.
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Curved Permanent Magnets: Optimized sinusoidal BEMF for smooth control.
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Optional Rotor Heightened Version (+3mm): Improves sensing accuracy with hall sensor setups.
Encoder & Feedback
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Compatible with high-resolution encoders from Renishaw, Sick, etc.
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Position Accuracy: Up to 0.01°
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Operating Range: -40°C to 85°C
Connector Wiring
| Signal | Color + Wire Type |
|---|---|
| U | Black + 18# Silicone Wire |
| V | Yellow + 18# Silicone Wire |
| W | Red + 18# Silicone Wire |
| Hu | Blue + 30# Silicone Wire |
| Hv | Green + 30# Silicone Wire |
| Hw | Yellow + 30# Silicone Wire |
| VCC | Red + 30# Silicone Wire |
| GND | Black + 30# Silicone Wire |
Correspondence:
Hu → U, Hv → V, Hw → W
Mechanical Drawing
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Outer Diameter: 54 mm
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Stator Inner Diameter: 22 mm ± 0.02 / 0.03
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Stack Height: 16 mm + 3 mm (if heightened rotor version is used)
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Max Rotor Diameter: 53 mm
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Hall Sensor Wiring: Integrated 5-pin signal + power plug
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Mounting Options: Multiple flexible configurations
Performance Chart
Tested at 24VDC, the RI50 KV100 motor exhibits:
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Peak efficiency at ~0.3 Nm
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Output power peaks around 1 Nm
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Stable torque with smooth deceleration curve
Manual Downloads
RI50 without hall sensor-3D.zip
Applications
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Collaborative Robot Arms (Cobot)
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Exoskeletons
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Lightweight Legged Robots
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Quadruped Robot Joints
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Precision Actuation in Industrial Automation
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Medical Robots and Research Platforms
Details

CubeMars RI50 motor dimensions: 54mm diameter, 19mm length, no hall sensor.

CubeMars RI50 Motor with hall sensor. Dimensions: 54mm diameter, 30.6-53mm length. Features R1.05, R1.7 radii, 60° angle, and 190±5mm span. Includes red, black, yellow wires for VCC, GND, signal.

CubeMars RI50 Motor: 24/36/48V, 1090/1860/2600 RPM, 0.58 Nm torque, 4.8 A current. Insulation class C, -20°C to 50°C operation, 7 pole pairs, 180.8g weight, 9.24 Nm/Kg max torque weight ratio.

Analysis Chart for CubeMars RI50 KV100@24VDC motor. Displays output power (W), efficiency, current (A), and speed (RPM) against torque (N.m). Output power peaks at approximately 72W near 0.8 N.m. Efficiency reaches a maximum around 0.8 at low torque. Current increases linearly with torque. Speed starts at 2500 RPM and decreases as torque rises. Graph illustrates motor performance characteristics under varying loads, highlighting optimal operating points for power, efficiency, and speed.

CubeMars RI50 motor: 24/36/48V, 66W, 0.58Nm torque, 4.8A current, 1090-2600RPM speed, 1.67Nm peak torque, 14.8A peak current, 2004-4008RPM no-load speed, 1420mΩ resistance, 1500μH inductance, 7 pole pairs, 180.8g weight, φ54*27mm size.

CubeMars RI50 Motor: Lower cogging torque, smooth running, low noise, strong dynamic.

RI50 rotor heightened version; overall height increased by 3mm for improved hall sensor sensing.

Curved permanent magnet for BEMF Sinus motor design ensures easy control.

Hand-wound stator with 0.5mm clearance for optimal performance.

CubeMars RI50 Motor: -40°C to 85°C, high precision, encoder options.
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