Search results
Results from the WOW.Com Content Network
One voltage cycle of a three-phase system. A polyphase system (the term coined by Silvanus Thompson) is a means of distributing alternating-current (AC) electrical power that utilizes more than one AC phase, which refers to the phase offset value (in degrees) between AC in multiple conducting wires; phases may also refer to the corresponding terminals and conductors, as in color codes.
Walter Bailys Polyphase motor (1879) marks the beginning of the development of modern polyphase motors. Mr. Mr. Bailey exhibited his invention on the Physical Society of London on June 28, 1879, on the occasion of his reading a paper entitled, "A Mode of Producing Arago's Rotations."
Motor pools that control flexor muscles are located dorsally to the ventral horn while those that control extensor muscles are located ventrally. [1] The number of motor neurons in an individual motor pool is highly variable and can generally be predicted by the level of nuanced control that a specific muscle requires.
The resulting source of polyphase power soon found widespread acceptance. The invention of the polyphase alternator is key in the history of electrification, as is the power transformer . These inventions enabled power to be transmitted by wires economically over considerable distances.
Groups of motor units often work together as a motor pool to coordinate the contractions of a single muscle. The concept was proposed by Charles Scott Sherrington. [2] Usually muscle fibers in a motor unit are of the same fiber type. [3] When a motor unit is activated, all of its fibers contract.
Polyphase coils are electromagnetic coils connected together in a polyphase system such as a generator or motor. In modern systems, the number of phases is usually three or a multiple of three. Each phase carries a sinusoidal alternating current whose phase is delayed relative to one of its neighbours and advanced relative to its other ...
General depiction of a motor unit, consisting of a motor neuron innervating a group of muscle fibers. Motor unit recruitment is the activation of additional motor units to accomplish an increase in contractile strength in a muscle. [1] A motor unit consists of one motor neuron and all of the muscle fibers it stimulates.
Motor learning is also accomplished on the musculoskeletal level. Each motor neuron in the body innervates one or more muscle cells, and together these cells form what is known as a motor unit. For a person to perform even the simplest motor task, the activity of thousands of these motor units must be coordinated.