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Cogging torque of electrical motors is the torque due to the interaction between the permanent magnets of the rotor and the stator slots of a permanent magnet machine. It is also known as detent or no-current torque. This torque is position dependent and its periodicity per revolution depends on the number of magnetic poles and the number of ...
A detent is a mechanical or magnetic means to resist or arrest the movement of a mechanical device. [1] Such a device can be anything ranging from a simple metal pin to a machine. The term is also used for the method involved. Magnetic detents are most often used to divide a shaft rotation into discrete increments.
Synchronous electric motors using permanent magnets have a resonant position holding torque (called detent torque or cogging, and sometimes included in the specifications) when not driven electrically. Soft iron reluctance cores do not exhibit this behavior.
A common example is "cogging torque" due to slight asymmetries in the magnetic field generated by the motor windings, which causes variations in the reluctance depending on the rotor position. This effect can be reduced by careful selection of the winding layout of the motor, or through the use of realtime controls to the power delivery.
The cogging torque is measured with a torque transducer connected between the test object and the load machine. The cogging torque can be determined in two different ways: Measurement of the cogging torque at slow speed or measurement of the cogging torque with closed-loop position control.
Hady Habib's history-making run at the Australian Open will continue after the first man to represent Lebanon in a Grand Slam singles tournament in the Open era became the first to win a match ...
Most motors exhibit positional torque ripple known as cogging torque. In high-speed motors, this effect is usually negligible, as the frequency at which it occurs is too high to significantly affect system performance; direct-drive units will suffer more from this phenomenon unless additional inertia is added (i.e. by a flywheel ) or the system ...
Alas, the Bills were penalized 10 yards and faced second-and-21 at their own 43-yard line instead of third-and-3 at the Baltimore 39. They punted two downs later after failing to secure a first down.