How to choose a planetary gear motor for your application

The planetary motor is an efficient reduction motor. It consists of several planetary gears around the sun gear. There’s also a ring gear that surrounds the planetarys. The advantages of the planetary gearmotor are its high efficiency and high torque density. It also has high precision, low sound, low vibrations, and low backlash. It is applicable in a variety of industrial and military fields such as robotics, aerospace, medical, food, chemical industry.

What is the right planetary motor for you? This article will explain the following:

Basic parameters of planetary dc gear motor

First of all, you need to understand what parameters the planetary gear motor has and what these parameters mean.

ParameterMeaningUnitExample
Input powerThe rated power of the motorWatts (W) or horsepower (hp)100 W or 0.134 hp
Output torqueThe rated torque of the gearboxNewton meters (N-m) or foot pounds (ft-lb)10 N-m or 7.38 ft-lb
Output speedThe speed of the output shaft of the speed reducerRevolutions per minute (rpm)100 rpm
Deceleration ratioThe ratio of the input speed of the reducer to the output speedFraction or colon10:1 or 10/1
EfficiencyThe ratio of the output power of the reducer to the input powerPercentage90%
ReturnThe angular displacement generated by the output shaft of the reducer in the absence of load, along the positive and negative direction of rotationAngle (°) or arc minutes (′)5° or 300′
NoiseThe sound pressure level generated by the reducer in operationDecibel (dB)60 dB
LifeThe operating time of the speed reducer in normal use conditions, to maintain its performanceHours (h)10000 h

Classification and characteristics of micro planetary gearbox

Do you know how many kinds of planetary gearbox with motor there are? What are they classified according to?

planetary-gear motor

1. According to the motor type

  • DC brushed planetary gear motor: Using DC brushed motor as the power source, it has the advantages of simple structure, low cost, easy control, and fast response, but it also has the disadvantages of short life, high maintenance, low efficiency, high noise, electromagnetic interference, etc., suitable for low-power, low-speed, and low-precision applications, such as toys, household appliances, and office equipment.
  • Brushless planetary gear motor: Brushless dc motor with planetary gearbox is used as the power source, which has the advantages of compact structure, long service life, low maintenance, high efficiency, low noise, and low electromagnetic interference, but brushless dc planetary gear motor also has the disadvantages of high efficiency. High cost, complex control, slow response, etc. Suitable for high-power, high-speed, and high-precision applications, such as robotics, aerospace, medical, and industry.
  • AC planetary gear motor: Using AC motor as the power source, it has the advantages of stable structure, long life, high efficiency, low noise, and low electromagnetic interference, but it also has disadvantages such as high cost, complex control, and slow speed. Suitable for high-power, high-speed, and high-precision applications, such as robotics, aerospace, medical, and industry.

2. According to the material of planetary gearboxes

  • Metal planetary gear motor: A gear reducer made of metal materials has the advantages of high strength, high stiffness, good wear resistance, and high carrying capacity, but it also has the disadvantages of high weight, high cost, high noise, and low efficiency. It is suitable for high-load, high-torque, and high-precision applications, such as robotics, aerospace, medical, industrial, etc.
  • Plastic planetary gears: Plastic materials are used in the manufacture of reducers. They have the advantages of light weight, low cost, low noise, and high efficiency, but they also have the advantages of low strength, low stiffness, poor wear resistance, and weak bearing capacity. Large capacity and other disadvantages, suitable for low-load, low-torque, and low-precision applications, such as toys, household appliances, and office equipment.

3. According to the series of the gearbox planetary gear

  • Single-stage planetary gear motor: There is only one set of sun wheels, planetary wheels and inner ring gear reducers. It has the advantages of simple structure, high efficiency, small return, and high accuracy, but it also has the disadvantages of limited speed. It has the characteristics of large reduction ratio, low torque density, and low noise. It is suitable for low reduction ratio and high-precision applications, such as robotics, aerospace, medical, industrial, etc.
  • Multi-stage planetary gear motor: There are two or more sets of sun wheels, planetary wheels and inner ring gear reducers, which have the advantages of large reduction ratio, high torque density, low noise, etc., But there are also disadvantages of complex structure, low efficiency, large backlash, low accuracy, etc., suitable for high reduction ratio, low precision applications, such as toys, household appliances, office equipment, etc.

Selection methods and precautions for planetary gear motor

After knowing the parameters and types of planetary motor gearbox, I believe you already have a general understanding of planetary gear motors. So when choosing to buy a planetary gear motor, how should you choose? What factors need to be considered?

FactorRequirementExample
Output torqueDetermine the output torque you need based on your load type, load size, safety factor and other factors, and then select a planetary gear motor that meets or slightly exceeds this value.If you need to lift a 100 kg load with a lever arm of 0.5 m, and you have a safety factor of 2, then you need an output torque of at least2×100×9.81×0.5=9812×100×9.81×0.5=981N-m.
Output speedCalculate the output speed you need based on your speed requirements, and then select a planetary gear motor that meets or is slightly less than this value.If you need to rotate the lever arm at 10 rpm, then you need an output speed of 10 rpm.
Reduction ratioCalculate the reduction ratio you need based on your input speed and output speed, and then select the planetary gear motor that is closest to or slightly larger than this value.If your input speed is 1000 rpm, and your output speed is 10 rpm, then you need a reduction ratio of 1000:10=100 or higher.
EfficiencyChoose a higher-efficiency planetary gear motor based on your energy needs. Generally speaking, the efficiency of DC brushless planetary gear motors and AC planetary gear motors is higher than that of DC brushed planetary gear motors. Single-stage planetary gear motors have higher efficiency than multi-stage planetary gear motors, and metal planetary gear motors have higher efficiency than plastic planetary gear motors.If you need to minimize the energy loss and heat generation of your planetary gear motor, then you should choose a DC brushless or AC planetary gear motor with a single-stage metal reducer.
BacklashAccording to your accuracy requirements, choose a planetary gear motor with smaller backlash. Generally speaking, the backlash of DC brushless planetary gear motors and AC planetary gear motors is smaller than that of DC brushed planetary gear motors. The backlash of single-stage planetary gear motors is smaller than that of multi-stage planetary gear motors. Metal planetary gear motors have smaller backlash than plastic planetary gear motors.If you need to achieve precise positioning and repeatability of your planetary gear motor, then you should choose a DC brushless or AC planetary gear motor with a single-stage metal reducer and a low-backlash design.
NoiseAccording to your noise requirements, choose a planetary reduction motor with smaller noise. Generally speaking, the noise of DC brushless planetary reduction motor and AC planetary reduction motor is smaller than the noise of DC brush planetary reduction motor and single-stage planetary reduction motor. Single-stage planetary gear motors are less noisy than multi-stage planetary gear motors, and plastic planetary gear motors are less noisy than metal planetary gear motors.If you need to reduce the noise level of your planetary gear motor, then you should choose a DC brushless or AC planetary gear motor with a single-stage plastic reducer and a low-noise design.
LifespanAccording to your life requirements, choose a planetary gear motor with a longer life. Generally speaking, the lifespan of DC brushless planetary gear motors and AC planetary gear motors is longer than that of DC brushed planetary gear motors, and metal planetary gear motors have longer life than plastic planetary gear motors.If you need to extend the life of your planetary gear motor, then you should choose a DC brushless or AC planetary gear motor with a metal reducer and a long-life design.
Motor typeAccording to your power supply type, control method, response speed and other factors, select the appropriate motor type, such as brushed DC, brushless DC, AC, etc.If you need to use a battery-powered planetary gear motor with variable speed control and fast response, then you should choose a brushless DC motor.
Reducer materialChoose the appropriate reducer material, such as metal, plastic, etc., according to your working environment, temperature, humidity, corrosiveness and other factors.If you need to use a planetary gear motor in a harsh environment with high temperature, humidity and corrosiveness, then you should choose a metal reducer with a protective coating.
Reducer seriesSelect the appropriate reducer series, such as single-stage, multi-stage, etc., based on your reduction ratio range, accuracy requirements, efficiency requirements and other factors.If you need to use a planetary gear motor with a high reduction ratio, high accuracy and high efficiency, then you should choose a single-stage reducer series.
Installation methodAccording to your space restrictions, direction requirements, connection methods and other factors, choose the appropriate installation method, such as flange type, shaft type, foot type, etc.If you need to mount your planetary gear motor horizontally on a flat surface, then you should choose a flange type installation method.
Size and weightChoose the appropriate size and weight based on your space constraints, carrying capacity, transportation costs and other factors. Generally speaking, size and weight are directly proportional to the output torque and inversely proportional to the output speed.If you need to use a planetary gear motor with a high output torque and a low output speed in a limited space, then you should choose a compact and lightweight planetary gear motor.

Choose Voltspin As your supplier of planetary gearbox with motor

At VoltSpin, our engineers meet the most stringent industry standards and continuously reform micro gear motors. Need 6mm planetary gear motor? 12 volt planetary gear motor? bldc planetary gear motor? Or planetary gear motor 24v? No matter what kind of electric motor planetary gearbox you need, our experts have the knowledge and experience to deal with them.


When other small planetary gear motor companies think your request is impossible to achieve, VoltSpin is always looking forward to your call. We are always ready to work with you in every detail to ensure that the final product meets your unique requirements. Contact our team today to tell us your needs, and the VoltSpin team will evaluate your project immediately.

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Conclusion

Miniature planetary gearbox play a vital role in a wide range of industries. Their efficient, compact design makes them a core component in a wide range of applications including automation equipment, industrial machinery, automotive systems and aerospace. Its precision drive train and reliability make it a favorite in applications requiring precise control and high torque output, providing a critical power solution for a variety of industries, and VoltSpin is ready to meet your electric motor with planetary gearbox manufacturing needs.

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