Motor solutions are the lifeblood for many applications. They make automation systems run.
While every automated system is different, there are just as many motor types to fit each application. There are countless motor types, brands and sizes making motor selection an important process.
AC motors convert electrical energy into mechanical energy, distributing an alternating current over long ranges. They are flexible, efficient, and tend to operate quietly, which makes them ideal for use in applications like pumps, fans, blowers and other applications that need either constant, variable, or adjustable speed control.
At the basic level, AC motors consist of a stator and a rotor that contains a conductor. The motor operates by rotating the conductor across a magnetic field to create voltage. If the conductor is in a closed field, current is created.
AC motors are used for multiple reasons including:
- Efficiency: they have high speed to torque, allowing them to operate without overheating or braking.
- Brushless: brushless motors do not create friction, which reduces heat output and increases the lifespan of the motor.
- Quiet: AC motors operate with a very low humming sound.
- Simple and Accessible: they have only one moving part. They also come in various shapes and sizes and with different power outputs, allowing them to fit into many applications.
- Speed Control: the frequency can be changed to control the speed of the motor.
Brushed DC Motor
Brushed DC motors are still used in applications that need high peak torques and run off of simple speed controllers. They are a cost-efficient motor that controls easily and has a linear torque-speed relationship.
Brushed DC motors are comprised of four components: a stator, rotor, brushes, and a commutator. They operate with permanent magnets on the outside of the motor to create an electromagnetic field. Their operation allows them to produce high torque during acceleration and deceleration, which makes them ideal for industrial applications that involve dispensing and packaging as well as some robotic applications.
The drawbacks to using brushed DC motors is the mechanical wear and tear on the brushes and the commutator, leading to a lower lifespan. However, their low initial cost can make up for their more frequent replacement needs.
Brushless DC Motor
Brushless DC motors are similar in function to brushed DC motors, with the primary difference being that they operate without brushes. A brushless DC motor is built opposite of a brushed DC motor. While a brushed DC motor has the magnets on the outside (the stator), brushless DC motors have their magnets on the interior rotor. They do not use brushes to create an electromagnetic field.
Brushless DC motors are quieter, more efficient, and have longer lifespans than brushed dc motors. They can also run continuously with less heat output. These benefits come with a slightly higher initial cost. Brushless DC motors are also ideal for hazardous environments that contain dust, grease, oil, and other contaminants.
Geared DC Motor
Geared DC motors (gearmotors) are motors that have a gear assembly attached to the motor. This assembly allows the motor to increase the torque and reduce speed as needed. This concept—increasing torque while decreasing speed—is known as gear reduction.
Gearmotors work in conjunction with gearboxes. They are small, have a high torque-to-size ratio, and can be used in tight spaces. This creates a smaller motor footprint.
Servo motors are typically used to convert rotary to linear motion as they have position and velocity feedback. They are specially designed to work in mechanical systems with a feedback device like an encoder or resolver. These types of motor have highly precise feedback but require a control to manage commutation and position/velocity control. The benefit of this is the user knows the motor’s position, speed, and torque at every moment, making them useful in robotics and industrial production.
Most servo motors today are brushless motors. They are accurate, reliable, and efficient, and can also be used in harsh environments. They also feature high acceleration, quiet operation, and closed-loop control. They have a high ratio of torque to inertia that is comparable to AC motors. Their downside is that they can be higher cost initially.
Many uses for servo motors include robotics, conveyor belts, metal cutting and forming machines, printing presses, CNC and machine tooling, and food and beverage packaging applications.
Need help choosing a motor for your system? Our automation experts can help. Get in touch with Motion Ai to learn more about your options.