Linear actuators are brought into the movement by a DC (Direct Current) motor, which is good at producing movement at a constant speed. The rotation speed of a motor depends on the voltage amount. The torque output of the motor, in turn, depends on the current power.
A DC motor allows adjusting the speed of rotation from a couple to thousands of revolutions per minute. This is the main feature that allows DC motors to be used in 12-volt actuators. A reliable supplier is always able to provide a wide variety of DC motors separately or in a system with actuators.
DC Motor Components and Types
A DC motor is made from 2 main components:
A stator;
A rotor.
The stator is a stationary part, it does not move. The rotor is, as you can guess, the part that performs the rotational movement. Depending on what other accessories are available, DC motors are classified into three main categories.
Brushed Motor
Here, the rotor part is made from conductors. These conductors are connected to isolated segments made from copper. These segments are called commuter. This commuter connects to the external source of power via carbon brushes.
The stator of a brushed motor (now, you know why it is called “brushed) is made from coils. They are interconnected. In these coils, the magnetic field is generated. It produces the so-called motor field current.
The presence of brushes though causes some drawbacks. They can overheat and they wear out. Thus, constant maintenance is needed.
Brushless Motor
A brushless motor was a logical development aimed to eliminate the drawbacks of the brushed motors. Brushes were removed. Thus, the need for maintenance was eliminated, and, as a result, the service life of the motor became longer.
A brushless motor brought some more benefits such as:
Reliability;
Low noise generation;
A precise speed control.
These benefits were brought due to the application of a more advanced drive circuit. However, because of the new type of drive circuit, the item also became more expensive.
Servo Motor
A servo motor is the latest development and is much more advanced than its ancestors. It consists of a regular DC motor, a positioning feedback item, and a reduction gearbox. The position of the shaft of the motor is controlled by the positioning feedback device and the data are sent to the control circuit of the servo motor.
The main benefit of the servo motor is its rotation ability. The motor can turn to up to 180 degrees. Thus, this item is perfect if a precise angular positioning is required.
The main drawback is that such motor type normally cannot deliver a continuous movement at a high speed. To make it able to do so, you shall modify the motor.
These three motor types are widely used in 12v actuators, depending on the actuator type and its application field. They allow 12v actuators have the advantages (constant speed, accurate positioning, etc.) that have made them so popular in many industries.
