What Is The Servo Drive?


The servo system in engineering is made out of 4 important components: the motor, the drive, the feedback device and the controller. The feedback device is normally an encoder while the servo drive and the controller work as a whole in order to determine motor needs. Then, these needs are communicated to a controller so that it can send the electrical energy that is necessary.

You can easily learn more about the servo drives in detail but some facts are more important than others. This is what we will focus on in the following paragraphs.

A controller needs to calculate the trajectory or path needed to then send voltage signals to a drive. A servo drive takes the data and then sends the voltage and current necessary to a motor in order to achieve the motion that is required. A servo drive can easily control torque, position or velocity. However, in the servo systems, torque stands out as the common parameter that is controlled.

In some circumstances, the servo drive is known as an amplifier. This is because it takes a control signal from a controller to amplify it.

Various servo drive types are available right now on the market. The common one is the torque mode servo drive. It converts a command issued by the controller into a specific motor current. Because of the fact that current is always directly proportional to the value of the torque, the servo drive controls how much torque a motor can produce.

In a servo system, the controller is basically the “brain”. Its job is to receive information offered by the feedback device. That information is used to send appropriate voltage signals to a servo drive. The servo drive is the “nervous system”. It sends the current amount that the motor needs. Because the process involves reading feedback and then responding, it is known as a closed loop system. This is one of the defining characteristics associated with servo systems.

In order to size the servo motor, torque-speed curve is taken into account. However, the torque-speed curve stands out as being specific to a specific drive-motor combination. Peak and continuous torque motor capabilities are always affected by thermal properties seen in the servo drive and the motor. Motor inefficiencies lead to heat production. This degrades insulation and lubrication around windings. When excessive heat is present, magnets can be demagnetized. The servo drive does not include parts that move but heat is capable of damaging power transistors.

Originally, the servo drive was a stand-alone component that was separated from the controller and the motor in a servo system. However, in the past 10 years, most motor manufacturers worked on integrated drive-motor systems. There are even systems that are complete controller-drive-feedback-motor systems. The use of such motors makes selection and sizing really easy, reduces necessary wiring and save a lot of setup time and needed space.

Servo drives are nowadays really useful in numerous engineering applications. However, some are better than others, based on who manufactures them. If you are to use a servo drive, buy the one that is the best.


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