In many types of applications, particularly for industrial and commercial use, a DC motor is an advantage over an AC motor. As a general statement, they are able to provide a higher torque upon starting as well as faster starting and stopping or reversing than a similar size of AC motor.
Aside from performance, which is always a central configuration, the DC motor is also typically less costly to operate over the AC systems, and it is an ideal match for applications where low horsepower is required. When correctly maintained, they are a very long lasting motor.
One of the challenges in choosing the DC option over the AC motor is that it can be difficult to choose the correct motor for the job. The key is in choosing the motor that offers the correct power to torque ratio for the given application.
Selection Criteria
There are two common types of motors in this category. They include the motors with brushes or those that use brushless technology. Of these two options, the brush motors are the most common, and they are designed with contact brushes that allow for the change in current direction.
These motors do need to have the brushes replaced as needed, and overheating of the brushes can be an issue if the motor is run at high speeds for extended periods of time. Ideally, they are used at speeds of less than 5,000 rpm.
With both types of the DC motor options, choosing a motor that fits into the power and the application requirements, including the ambient temperature where the motor is going to operate are also essential factors that impact performance and life cycle.
Working with engineers to determine the correct size and type in motors is always important for a new system and equipment design as well as choosing replacement motors.