When talking with a customer, there are three specs we like to know first: speed, torque and voltage. This is a good starting point for us, as we decide what motor best suits an application. Once we have those details, we can help the customer find either a catalog or custom motor to suit their needs. In some cases, more than one motor or gearmotor could fit the required specs for an application. Below we have an example to show a situation with more than one motor will meet the required specifications. The benefits of each option are considered, showing various details to think through when choosing a motor.
A customer has requested a Permanent Magnet DC motor with the following application requirements:
Application Requirements:
- 340 RPM running speed
- 9 in-lbs torque
- 24 VDC supply
There are several available designs to meet these specifications. Here we will compare two designs, a motor-only and a gear motor, and discuss the potential that each option offers an application. Although both units would run the example application successfully, with additional information regarding the application, we can determine which design’s strengths would be most beneficial for the project.
Solution Comparison:
Both designs can meet the continuous duty torque requirement and the cost of each is equal; however, the necessary addition of a speed control for the motor-only will add some cost.
Summary
There are other things to consider before choosing between the two options. For example, backlash can be important in applications that require tight positioning or reversing. Also, faster acceleration can be achieved with the motor-only design since there is more voltage available from the control. The gearmotor will work well for most industrial applications like pumps and conveyors.
This is just one example of how two motors can meet certain specifications. Keep in mind, that as the required torque is increased, it will become very impractical to use a motor-only design to drive the application. This is because the motor size will increase exponentially in order to meet the torque requirement.
Check out our whitepaper “The Basics of Motor Selection” for a more in-depth look at selecting the proper motor.
