Planetary Gear Motor GMP42
The GMP42 Planetary Gear Motor is a 42 mm-class planetary geared DC motor designed for compact, high-torque motion systems requiring stable speed reduction and reliable load handling. The supplied reference models cover 6 VDC and 18 VDC configurations, with rated speeds from 36 to 250 RPM and rated torque from 0.5 to 1.5 N·m. Its coaxial planetary gearbox is well suited for robot joints, AGV/AMR drive mechanisms, industrial automation, smart equipment, and other compact actuators.
Product Overview
The GMP42 Planetary Gear Motor is a 42 mm-class planetary geared DC motor designed for compact, high-torque motion systems requiring stable speed reduction and reliable load handling. The supplied reference models cover 6 VDC and 18 VDC configurations, with rated speeds from 36 to 250 RPM and rated torque from 0.5 to 1.5 N·m. Its coaxial planetary gearbox is well suited for robot joints, AGV/AMR drive mechanisms, industrial automation, smart equipment, and other compact actuators.
Model Information
| Series | Motor Type | Product Category |
| GMP42 | PMDC Motor | Planetary Gear Motor |
Main Parameters
Gearmotor Technical Data
| Model | Ratio | Rated Voltage | No-load Speed | No-load Current | Rated Speed | Rated Current | Rated Torque | Stall Current | Stall Torque |
| GMP42M755-216K | — | 6 VDC | 43.5 RPM | ≤3.0 mA | 36 RPM | ≤12 mA | 0.5 N·m / 5.0 kgf·cm | ≤55 mA | 1.5 N·m / 15 kgf·cm |
| GMP42M775-36K | — | 18 VDC | 275 RPM | ≤1.0 mA | 250 RPM | ≤7.2 mA | 1.5 N·m / 15 kgf·cm | ≤52 mA | 8.0 N·m / 80 kgf·cm |
PMDC Motor Reference Data
| Motor | Motor Length | Rated Voltage | No-load Speed | No-load Current | Rated Speed | Rated Current | Rated Torque | Stall Current | Stall Torque |
| SL-755 | 69.5 mm | 6 VDC | 9500 RPM | ≤2.3 mA | 7850 RPM | ≤11 mA | 50 mN·m / 500 gf·cm | ≤52 mA | 305 mN·m / 3050 gf·cm |
| SL-775 | 110 mm | 18 VDC | 10000 RPM | ≤0.8 mA | 9000 RPM | ≤6.5 mA | 85 mN·m / 850 gf·cm | ≤50 mA | 750 mN·m / 7500 gf·cm |
Dimension Drawing

Main Applications
Customization Range
Electrical Configuration
Rated voltage and motor selection based on target speed, torque, current, and duty cycle.
Performance Matching
Gear ratio, output speed, continuous / starting / peak torque, current limit, and load margin.
Mechanical Interface
Output shaft shape and length, mounting flange, gearbox length, bearing configuration, and installation interface.
Feedback Options
Hall sensor or encoder configuration can be evaluated according to speed, position, or stall-detection requirements.
Backlash / Noise Optimization
Gear precision, assembly fit, lubrication, speed matching, and complete-product resonance can be evaluated.
Reliability Validation
Frequent start-stop, reverse impact, temperature rise, axial/radial load, vibration, shock, and application-specific life cycle.
FAQ
Q1. What applications are planetary gear motors best suited for?
Planetary gear motors are ideal for applications that require high torque density, compact size, stable transmission, and relatively low backlash. Typical applications include robot joints, grippers, AGV/AMR wheel drives, medical devices, automotive actuators, smart home mechanisms, and industrial automation equipment.
Q2. How should I choose the gear ratio and output torque?
The gear ratio should be selected based on the required output speed, load torque, motor speed, operating time, and duty cycle. A ratio that is too low may not provide enough torque, while an excessively high ratio may reduce output speed and increase transmission stages, noise, cost, and mechanical losses. Continuous, starting, and peak torque should all be evaluated during selection.
Q3. Can planetary gear motors be used for precision positioning?
Yes. Planetary gear motors can be designed with controlled backlash and combined with encoders or Hall sensors for position and speed feedback. However, final positioning accuracy also depends on gearbox backlash, sensor resolution, mechanical stiffness, assembly tolerances, and the control algorithm, so system-level validation is recommended for precision applications.
Q4. How do you evaluate reliability and service life?
Reliability should be validated under the customer’s actual operating conditions, including load, start-stop frequency, reversing cycles, temperature, shock, vibration, and duty cycle. Key performance items such as speed, current, torque, temperature rise, noise, backlash, and gear wear can be monitored during life testing.
Q5: How do I place an order with Shunli Motor?
Please send us your application requirements or motor specifications. Our engineering team will develop a suitable solution, confirm the technical details, and provide samples for evaluation. Once the samples are approved, we will arrange mass production. Shipping methods can be selected based on your delivery requirements.
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