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Scalar Control
Scalar control of an AC electrical motor is a way to achieve the variable-frequency drive, variable speed operation by manipulating the supply voltage or current ("magnitude") and the supply frequency while ignoring the magnetic field orientation inside the motor. Scalar control is based on equations valid for a steady-state operation and is frequently open-loop (no sensing except for the current limiter). The scalar control has been to a large degree replaced in high-performance motors by Vector control (motor), vector control that enables better handling of the transient processes. Low cost and simplicity keeps the scalar control in the majority of low-performance motors, despite inferiority of its dynamic performance; vector control is expected to become universal in the future. Types The variants of the scalar control include open-loop control and closed-loop control. Open-loop The most common approach makes the voltage V proportional to frequency f (so called V/f control, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Motor
An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate force in the form of torque applied on the motor's shaft. An electric generator is mechanically identical to an electric motor, but operates with a reversed flow of power, converting mechanical energy into electrical energy. Electric motors can be powered by direct current (DC) sources, such as from batteries, or rectifiers, or by alternating current (AC) sources, such as a power grid, inverters or electrical generators. Electric motors may be classified by considerations such as power source type, construction, application and type of motion output. They can be powered by AC or DC, be brushed or brushless, single-phase, two-phase, or three-phase, axial or radial flux, and may be air-cooled or liquid-cooled. Standardized motors provide con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
