Planetary Gear Motors vs. Spur Gear Motors

Planetary and Spur gear motors are the two most common types of gear motors used in industrial applications. ISL Products is experienced in designing and manufacturing both Planetary Gear Motors and Spur Gear Motors. Our unique and collaborative approach ensures that our gear motors work optimally in your specific application. When trying to decide which gear motor is best suited for your application, there are a few key aspects to keep in mind. Both gear heads have their own unique advantages and disadvantages, based on the intended usage and requirements. ISL Products has an extensive history designing and manufacturing both planetary gear motors and spur gear motors. ISL tailors each gear motor specifically to meet our customer’s application requirements. As an industry leader in gear motors, ISL offers both our brushed and brushless DC motors with our planetary and spur gear heads.

Planetary Gear Motor and Spur Gear Motor
Planetary Gear Motor & Spur Gear Motor



Planetary Gear Head Construction

The gears inside of a planetary gear head have a unique method of meshing together. They have an internal gear, called the sun gear. The sun gear drives multiple outer gears known as planetary/satellite gears. The planetary/satellite gears mesh with an outer ring to guide and hold them in place. The outer ring is fixed and incorporated in the motor housing.  Since the internal sun gear meshes with multiple outer gears at once, planetary gear motors are able to sustain higher loads.


The ability to distribute the load over multiple contact points makes planetary gear motors optimal for high torque, high RPM applications like industrial machinery. Due to their versatility, planetary gear motors are also excellent choices for less demanding applications like articulating television mounts. Let us help you choose the right planetary gear motor for your application, discuss your requirements with an engineer today!

Spur Gear Head Construction

A spur gear head’s construction consists of larger gears that mesh with smaller gears. The gears are mounted on parallel shafts but offset from one another. The meshing of the smaller gears with the larger gears reduces rpm transforming it into torque. The tooth pitch of the gears is critical in determining the final output speed and torque of the gear motor.  Adding multiple gear stages within the gear head produces larger reduction ratios resulting in even lower output speed and higher output torque. Spur gearheads have a single contact point at any time. This means that any load is held entirely by a single point of contact between two gears.

A spur gear motor is a cost effective solution, suited for low torque and low RPM applications such as an automated paper towel dispenser. Over the years ISL has manufactured a variety of different spur gear motors for a variety of applications. Submit your Gear Motor requirements today and let us help make your application more efficient.

Torque & Speed

The two main parameters that are commonly associated with gear motors are torque and speed. When it comes to torque and speed, a planetary gear motor is more effective in high speed, high torque applications. As mentioned above, the multiple contact points between the gears of a planetary gear head are the reason for its effectiveness in these conditions.

The less complex construction of a spur gear head results in them not being able to hold as much of a load as their planetary counterpart. As the spur gear motor’s speed increases, it will produce a fair amount of noise without the proper internal lubrication. The ability to add multiple stages and have high gear reduction ratios allows spur gear motors to handle higher loads if needed.

In planetary gear systems the gear lubrication tends to stay within the teeth of the gears whereas, with spur gear systems, the lubrication tends to disperse from the gears at higher speeds.


ISL’s planetary gear motors are most commonly used in robotic and industrial automation applications. Some of our largest customers incorporate our planetary gear motors into industrial label printing machines, tactical robotics, vinyl cutting machines, and laser measuring apparatuses. The high precision and efficiency of our motors ensure that all types of applications operate at the highest level.

Low speed applications that benefit from ISL’s spur gear motors are automated paper towel dispensers, telescope positioning equipment and electromechanical door locks. Higher speed applications where our spur gear motors are used include small appliances, such as blenders and food processors.

Explore other application specific solutions that ISL Products has offered by reading some of our case studies.

Choosing the Right Gear Motor for Your Application

Choosing the proper gear motor configuration depends on the specifications required and the given application. This decision can often be time consuming; we invite you to contact our engineers for assistance. You can also use our Motor / Gear Motor Selection Tool to help summarize your requirements.

Although spur gear motors work best in low speed, low torque situations, with the right reduction ratios, ISL can produce a spur gear motor with more torque while still offering excellent efficiency. The simplicity and cost-effectiveness of our spur gear motors are the main selling points.

Our planetary gear motors are alternative solutions that are capable of handling heavier loads. In addition to their durability, planetary gear motors also provide a higher efficiency over spur gear motors.

Due to the construction of a planetary gear head, the length of a planetary gear motor is usually longer and narrower than spur gear motors. If you have certain size constraints within your application, please keep those in mind when deciding on your next gear motor.

ISL Products can manufacture both spur gear motors and planetary gear motors tailored specifically to your needs. Our engineers are ready to work with you on your next project, contact us today!

Gear Motor Advantages and Disadvantages

Check out all of our design notes for more information relating to our electronic and electromechanical components.


  • Spur gears: What are they and where are they used,
  • The DC Planetary Gear Motor vs. Spur Gear Motors,
  • Characteristics of Gears,
  • Gearbox Guide,
  • Understanding, Selecting and Applying Planetary Gearheads,
  • Planetary Gearhead,
  • Spur Gearhead,
  • Planetary Gearhead,