There are both kinds. Closed and open loop.
Some are simple voltage controllers, others use stepper technology and some use feedback from the motor to determine speed.
A closed loop will require feedback from the motor, to determine speed and correct it, either by tachometer or pulse detection.
A servo drive is any motor controller which uses a closed feedback loop to monitor the motors speed. This is normally accomplished through the use of an encoder or resolver.
A servomotor is an electromechanical device that converts electrical energy into precise mechanical motion. It operates using a closed-loop control system, which includes a motor, a feedback sensor, and a controller. The controller sends signals to the motor to adjust its position, speed, or torque based on the feedback received from the sensor, ensuring accurate and consistent performance. This makes servomotors ideal for applications requiring high precision, such as robotics and CNC machinery.
In industry closed control is a closed loop feedback where a pump or motor has an encoder or feedback device to keep the operation regulated.
An open loop traffic signal just cycles on a schedule and has no "knowledge" of traffic patterns or current traffic. A closed loop system would have sensors letting it know when traffic was present and a controller that would make decisions based on the traffic conditions.
A stepper motor (or step motor) is a brushless, synchronous electric motor that can divide a full rotation into a large number of steps. The motor's position can be controlled precisely, without any feedback mechanism (see Open-loop controller). Stepper motors are similar to switched reluctance motors (which are very large stepping motors with a reduced pole count, and generally are closed-loop commutated.) An induction motor (IM) is a type of alternating current motor where power is supplied to the rotating device by means of electromagnetic induction.
what does a graph look like of for a closed loop & one for an open loop of the controller's output over time for a step change in the desired value of 10% assume the controller is set at P.B. =100% and Ti=30 seconds
In a closed loop system the gain without the feed back loop being closed is called open loop gain!!! e.g if forward gain is "A" and feed back factor is "B" then open loop gain is "AB" and closed loop gain will be [A/(A+B)]
Feedback oscillators have a closed loop gain of
closed loop system
Sudesh K. Sethi has written: 'Analysis of a motor-generator system containing a speed loop, current limit loop, and position control loop'
the motor should only rotate in a rated speed,if the speed is more than rated speed then the motor will be damaged........to control the speed of motor a rheostat should be connected to the field side of motor......by variying the rheostat we can control the speed of motor......
A cruise control is an example of a closed loop servo.