How to Select a DC Motor

DC motors are vital components to any motion system – they provide the initial power and impetus to make the whole thing work. However, for optimal function, reliability and lifetime, it is critical to select the right motor for the job. When selecting a DC motor for your own application, you will need to understand a few variables.

Available Voltage

First and foremost, you will need to know the power available for the system. Choosing a motor that requires more power than you can give it is useless, while choosing one that does not need as much as you are giving it can be inefficient or damage the motor.

Output Requirements

You’ll also want to understand the speed and torque you want your motor to produce, as a mismatch in either can lead to a system that doesn’t work or a broken component. Holding voltage constant, torque and speed have an inverse relationship – so the more torque, the lower the speed, and the more speed, the lower the torque.

Physical Space

Here’s one requirement that’s truly non-negotiable. You’ll need to understand the physical space in your system for the motor so you can select a motor with a profile that fits into your system and won’t be too large. Depending on the nature of the system, you may also want to consider the weight of the motor as well.


Finally, it’s absolutely critical to understand and consider the operating environment. While most motors work great at 75º F at ambient atmospheric pressure, many will break down in extreme temperature environments, at high or low air pressure, or in the absence of contaminants or corrosive chemicals. When selecting a motor, be sure you consider all of these factors.

Contact Your Servo Drive System Experts

Have more questions about choosing the right DC motor or want to look into servo drives to control it? We’d be happy to help. Feel free to call us at 800.823.3235, reach out to us at our contact page, or find out more about the industries our servo drives operate in. We can’t wait to hear from you, and we hope to see you back at this blog for more tips and info on optimizing your motor control systems.