More about Servo Motors

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Servo motors are used to drive servos, which are systems that control mechanical motion at a location different than that of the primary controls. Servos typically operate through an electric or hydraulic connection to the control system. This means that an operator may position a control stick in one room, thereby transmitting a series of signals to a servo in a nearby room. The servo system will properly translate the signal from the control device and activate the servo motor accordingly, performing the movement indicated by the controller.

In essence, there is no specific difference between a servo motor and an ordinary motor. However, servo motors are generally smaller and designed for more dynamic performance and steady state accuracy. Generally, a servo motor also implies a link to a feedback control loop, as well as precise motion and high torque-to-inertia ratios. This motion should have the same degree of accuracy and torque in both rotational directions. Servo motors also imply high armature resistance, and more obviously, an electric powered device; hydraulic motors are sometimes used when larger power output is required.

Like other electric motors, servo motors fall into two main categories: Alternating Current and Direct Current. DC servo motors are used for small and mid-level applications requiring moderate and low power output, while AC servo motors are used in more heavy-duty applications. Within these categories, there are further distinctions, such as brushless DC motors, split series motors, shunt control motors and permanent magnet motors. Each type has specific advantages and disadvantages, and should be chosen based on application and budget. For example, brushed DC motors are relatively inexpensive, but are more prone to maintenance concerns than brushless types.

Servo motors are found in a wide range of devices, including computers, robots, guidance systems and automated manufacturing mechanisms. Generally, their components include an electromagnet, rotating shaft (often connected to a gear train), motor housing and power input, although parts vary between designs. Materials used in construction include various metals and synthetics, such as copper, polyethylene and stainless steel.