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A permanent magnet synchronous motor and reluctance motor requires a control system for operating (VFD or servo drive). There is a large number of control methods for synchronous machines, selected depending on the construction of the electric motor and the scope. Control methods can be divided into: [21] [22] Scalar control. V/f control ...
Reduced starting current is desirable where the electrical grid is not of sufficient capacity, or where the driven load cannot withstand high starting torque. One basic method to reduce the starting current is with a reduced voltage autotransformer with taps at 50%, 65% and 80% of the applied line voltage; once the motor is started the ...
It is used to dampen the transient oscillations and facilitate the start-up operation. [ 2 ] Since the design of a damper winding is similar to that of a asynchronous motor , the winding technically enables the direct-on-line start and can even be used for the motor operation in the asynchronous mode.
The circle diagram can be drawn for alternators, synchronous motors, transformers, induction motors. The Heyland diagram is an approximate representation of a circle diagram applied to induction motors, which assumes that stator input voltage, rotor resistance and rotor reactance are constant and stator resistance and core loss are zero.
Self-starting polyphase induction motors produce torque even at standstill. Available squirrel-cage induction motor starting methods include direct-on-line starting, reduced-voltage reactor or auto-transformer starting, star-delta starting or, increasingly, new solid-state soft assemblies and, of course, variable frequency drives (VFDs). [39]
Electric machines, in the form of synchronous and induction generators, produce about 95% of all electric power on Earth (as of early 2020s), [4] and in the form of electric motors consume approximately 60% of all electric power produced. Electric machines were developed beginning in the mid 19th century and since that time have been a ...
A motor soft starter is a device used with AC electrical motors to temporarily reduce the load and torque in the powertrain and electric current surge of the motor during start-up. This reduces the mechanical stress on the motor and shaft, as well as the electrodynamic stresses on the attached power cables and electrical distribution network ...
==Starting methods== Small synchronous motors are able to start without assistance due to the low mass of the rotor, and the low starting current needed to rapidly accelerate the rotor to full speed from a dead stop. Synchronous motors are commonly used in line-powered electric mechanical clocks that use the powerline frequency to run the gear ...