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Schematic of a permanent magnet motor using brushes and magnets in the stator. A permanent magnet motor is a type of electric motor that uses permanent magnets for the field excitation and a wound armature. The permanent magnets can either be stationary or rotating; interior or exterior to the armature for a radial flux machine or layered with ...
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 ...
Patent sketch of Howard Johnson's magnet motor. Since the middle of the 20th century, a number of inventors claimed to have constructed various magnet motors. In 1954, German mechanical engineer Friedrich Lüling claimed to have realized a motor which could run with its permanent magnets for 10 to 20 years without interruption.
It is also known as short-circuit test (because it is the mechanical analogy of a transformer short-circuit test), [1] locked rotor test or stalled torque test. [2] From this test, short-circuit current at normal voltage , power factor on short circuit, total leakage reactance , and starting torque of the motor can be found.
A permanent magnet (PM) motor does not have a field winding on the stator frame, instead relying on PMs to provide the magnetic field against which the rotor field interacts to produce torque. Compensation windings in series with the armature may be used on large motors to improve commutation under load. Because this field is fixed, it cannot ...
The term back electromotive force is also commonly used to refer to the voltage that occurs in electric motors where there is relative motion between the armature and the magnetic field produced by the motor's field coils or permanent magnet field, thus also acting as a generator while running as a motor. This effect is not due to the motor's ...
In one arrangement, the motor has an ordinary stator. A squirrel-cage rotor connected to the output shaft rotates within the stator at slightly less than the rotating field from the stator. Within the squirrel-cage rotor is a freely rotating permanent magnet rotor, which is locked in with rotating field from the stator.
The motor from a 3.5 in floppy disk drive. The coils, arranged radially, are made from copper wire coated with blue insulation. The rotor (upper right) has been removed and turned upside-down. The gray ring inside its cup is a permanent magnet. This particular motor is an outrunner, with the stator inside the rotor. DC brushless ducted fan. The ...