Hyperkinesia
A tic can be defined as a repeated, individually recognizable, intermittent movement or movement fragments that are almost always briefly suppressible and are usually associated with awareness of an urge to perform the movement. These abnormal movements occur with intervening periods of normal movement. These movements are predictable, often triggered by stress, excitement, suggestion, or brief voluntary suppressibility. Many children say that the onset of tics can stem from the strong urge to move. Tics can be either muscular (alter normal motor function) or vocal (alter normal speech) in nature and most commonly involve the face, mouth, eyes, head, neck or shoulder muscles. Tics can also be classified as simple motor tics (a single brief stereotyped movement or movement fragment), complex motor tics (a more complex or sequential movement involving multiple muscle
groups), or phonic tics (including simple, brief phonations or vocalizations).
AC motor
Several methods of starting a polyphase motor are used. Where a large inrush current and high starting torque can be permitted, the motor can be started across the line, by applying full line voltage to the terminals (direct-on-line, DOL). Where it is necessary to limit the starting inrush current (where the motor is large compared with the short-circuit capacity of the supply), the motor is started at reduced voltage using either series inductors, an autotransformer, thyristors, or other devices. A technique sometimes used is star-delta (YΔ) starting, where the motor coils are initially connected in star configuration for acceleration of the load, then switched to delta configuration when the load is up to speed. This technique is more common in Europe than in North America. Transistorized drives can directly vary the applied voltage as required by the starting characteristics of the motor and load.