Search results
Results from the WOW.Com Content Network
Small variable-frequency drive Chassis of above VFD (cover removed). A variable-frequency drive (VFD, or adjustable-frequency drive, adjustable-speed drive, variable-speed drive, AC drive, micro drive, inverter drive, variable voltage variable frequency drive, or drive) is a type of AC motor drive (system incorporating a motor) that controls speed and torque by varying the frequency of the ...
A variable speed motor drive is a system that includes a motor that is continuously variable in speed. If the motor is generating electrical energy rather than using it, the motor drive could be called a generator drive but is often still referred to as a motor drive.
In vector control, an AC induction or synchronous motor is controlled under all operating conditions like a separately excited DC motor. [21] That is, the AC motor behaves like a DC motor in which the field flux linkage and armature flux linkage created by the respective field and armature (or torque component) currents are orthogonally aligned such that, when torque is controlled, the field ...
Direct torque control (DTC) is one method used in variable-frequency drives to control the torque (and thus finally the speed) of three-phase AC electric motors.This involves calculating an estimate of the motor's magnetic flux and torque based on the measured voltage and current of the motor.
To obtain a variable speed response, brushless motors operate in an electromechanical system that includes an electronic motor controller and a rotor position feedback sensor. [21] Brushless DC motors are widely used as servomotors for machine tool servo drives. Servomotors are used for mechanical displacement, positioning or precision motion ...
The speed and torque characteristics of a wound-rotor motor can be adjusted by changing the external resistance, unlike a squirrel cage motor which has a fixed characteristic. This is useful for speed control of the motor. [1] A wound-rotor motor can be used in several forms of adjustable-speed drive. Common applications include hoists and ...
In industry, a common application is the variable speed drive (VSD) that is used to control an induction motor. The power range of VSDs starts from a few hundred watts and ends at tens of megawatts. The power conversion systems can be classified according to the type of the input and output power: AC to DC ; DC to AC
The Beier variable-ratio gear or Beier variator is a mechanical drive offering a continuously variable gear ratio between input and output. The gear relies on the inter-meshing of a number of thin disks. By varying their separation, the effective radius of one disk varies, thus changing the overall gear ratio.