The Three Types of DC Motors

Our 12 volt linear actuators are powered by Direct Current (DC) motors as they are ideal for producing continuous movement and controlling the speed and position. The speed of rotation of a basic DC motor is dependent on the amount of DC voltage applied while the torque output is dependent on the amount of current. The rotation speed can vary anywhere from just a couple revolutions per minute to over a thousand revolutions per minute which is why DC motors can be utilized in such a variety of applications such as our 12V actuators.

PA-14 DC Motor

A DC Motor for our PA-14 Mini Actuator

DC motors are made up of two main parts, a Stator (the stationary part) and a Rotor (the rotating part). These two parts make up a DC motor which in turn can lead to three basic types of a DC motor; a Brushed motor, a Brushless motor and a Servo motor.

Brushed Motor: In a brushed motor the stator is an electromagnetic circuit that consists of electrical coils that are connected together to produce a stationary magnetic field system for rotation. The current that flows in these coils is called the motor field current. The rotor part of the motor consists of current carrying conductors connected at one end to isolated electrical copper segments known as the commuter. This commuter allows an electrical connection to an external power supply thanks to carbon brushes, which is why it is referred to as a “Brushed” motor.

Brushless Motor: This motor was developed to overcome the disadvantages of a brushed motor, mainly the fact that it doesn’t have to replace any brushes due to them overheating or wearing out. This in turn increases the lifespan of the motor. The brushless motor uses a more complex drive circuit that allows for more precise control over speed and torque. Other advantages over the brushed motor include its efficiency, reliability and low noise output. However with these advantages come a few disadvantages such as the price being much more expensive then regular brushed motors as well as being harder to control.

Servo Motor: These are used in closed loop systems where the position of the output motor shaft is sent to the motor control circuit. The servo motor generally consists of a DC motor, a reduction gearbox, a positional feedback device (like a potentiometer found in our PA-14P linear actuators) and a form of error correction which controls the speed and position. Most servo motors are able to rotate up to 180 degrees in both directions which makes them perfect for when you need highly accurate angular position control. A disadvantage to using a servo motor is the fact that it is unable to rotate at continually high speeds like most DC motors unless it is specially modified.

These three types show just how adaptable DC motors are and why we use them in our 12V actuators. They allow for precise control over the speed, direction and position of our actuators and are utilized in a variety of applications and industries. Hopefully this has given you more information on the motors that power our 12V actuators.

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