A comparison of Planetary and Spur Gear Motors

Charlotte Miller

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Planetary gear motors and spur gear motors are the two most common forms of industrial gear motors. It’s critical to choose the proper motor for your application in order to get the best results. But, if you are unfamiliar with these sorts of drives, selecting the appropriate one might be challenging.

Continue reading for a quick description of each, as well as differences between them, to help you select that will make the process easier.

What are Planetary Gear Motors and Spur Gear Motors?

Planetary Gear Motors

When more torque is required, the planetary gear motor distributes the torsional stress across many planetary gears. Torque is a twisting force that causes buildings or, in this example, gears to rotate. Torsion is defined as the bending of an item as a result of applied torque in strong mechanics. In cars or railcar movers with many gears operating at the same time, more torque is necessary.

The input shaft powers the centre gear, also known as the sun gear, which then turns the surrounding gears, also known as the planet gears, simulating the planetary rotating system.

This mechanism allows each of the planet’s gears to create sufficient torque in perfect alignment with one another, removing the weight off each gear and reducing the likelihood of the Gear motor failing, resulting in improved performance ability.

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Spur Gear Motors

A spur gear is a cylindrical gear having shafts that are parallel and coplanar, as well as spur teeth that are parallel to the output shaft. Spur gears are the most basic and widely used form of gear, as they are simple to make and suited for a broad range of applications.

The spur gear motor is easier to build and may be less expensive than a planetary gear motor. Spur gear motors are ideal for applications requiring minimal torque. Because each gear carries the entire load, the torque is restricted by the gear motor’s speed.

Structure of Planetary Gear Motors and Spur Gear Motors?

Planetary Gear Motors

Planetary Gear Motors are cylindrical in shape and are available in a wide range of power and size. Steel or brass are commonly used for planetary gear motors. Because this type of gear motor includes several gears and teeth that share load, there is less worry about wear and tension, making it simpler to transmit large amounts of power without harming the gears. 

Planetary gear drives are also more expensive to produce due to the additional components required. The sun’s gear, the outer gear, various planetary gears, and a moving arm to transport the planet’s gears are all included. While this system provides greater durability and reduced gear noise, it is generally more intricate, with portions that are difficult to access or unavailable, making repairs difficult.

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Spur Gear Motors

Typically, spur gear motors are composed of brass or steel. Spur gear motors are typically cylindrical in shape, and the gears can be loud, especially if not well lubricated. Straight-toothed gears are attached to parallel shafts, delivering strong torque at low speeds. 

For spur gears, the size of the gears and the number of teeth on each gear are essential design concerns. The gear ratios for output torque and shaft speed are determined by the size and number of teeth. Inadequate lubrication can weaken the teeth, resulting in throttle tension or slippage, as well as the gear motor being destroyed. Spur gear motors are less expensive to manufacture than planetary gear motors because they have fewer moving parts.

Planetary Gear Motors VS Spur Gear Motors

PRICE Planetary gear motors are costly than Spur gear motors
NOICE Spur gear motors are noisier than planetary gear motors
EFFICEINCY Planetary gear motors have a better efficiency than spur gear motors.
SIZE Same 

Application of Planetary Gear Motors and Spur Gear Motors

Physical restrictions may limit your gear selection, but more often than not, you will engineer your gear before developing housing for it. Nonetheless, each type of gear has its own set of design requirements.

Steel or brass are commonly used for spur gear motors. These are gears with straight teeth that link parallel shafts and generate great torque at low speeds. The size of the gears and the number of teeth on each of those gears are important design elements. This affects the output torque and shaft speed gear ratios. Spur gear motors are typically cylindrical, although they may take on various forms as well. The gears can be loud, especially if they aren’t well lubricated. Inadequate lubrication can also result in broken teeth, which can cause gear slippage or stress, resulting in gear motor failure. Spur gear motors are less expensive to manufacture than planetary gear motors, owing to the fact that they have fewer gears and are simpler.

For spur gear motors, steel or brass are frequently utilized. Straight-toothed gears connect parallel shafts and create a lot of torque at low speeds. The number of teeth on each gear, as well as the size of the gears, are key design aspects. This has an impact on the shaft speed gear ratios and the output torque. The gears may make a lot of noise, especially if they aren’t properly greased. Inadequate lubrication can also produce damaged teeth, which can lead to gear slippage or stress, which can lead to gear motor failure. Because they contain fewer gears and are smaller, spur gear motors are less expensive to produce than planetary gear motors.

In a nutshell, spur gears are excellent for applications that need low torque and low speed. If you require a lot of torque and speed, a DC planetary gear motor is a superior option.


We’ve included all you need to know about how and which gear motors function best in your application. There are a few crucial considerations to evaluate when deciding which gear motor is ideal for your application. Based on the intended purpose and needs, each gear head has its own set of benefits and drawbacks.

If you have any more queries, please feel free to contact us or go through the other articles in our knowledge center. Click here for more information about DC gear motor and Planetary gear motor.