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Rotary Switch
A rotary switch is a switch operated by rotation. These are often chosen when more than 2 positions are needed, such as a three-speed fan or a CB radio with multiple frequencies of reception or "channels". A rotary switch consists of a spindle or "rotor" that has a contact arm or "spoke" which projects from its surface like a cam. It has an array of terminals, arranged in a circle around the rotor, each of which serves as a contact for the "spoke" through which any one of a number of different electrical circuits can be connected to the rotor. The switch is layered to allow the use of multiple poles; each layer is equivalent to one pole. Alternatively the rotation can be limited to a fraction (half; third etc.) of a circle and then each layer can have multiple (two; three etc.) poles. Usually, such a switch has a detent mechanism so it "clicks" from one active position to another rather than stalls in an intermediate position. Thus a rotary switch provides greater pole and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fan (implement)
A handheld fan, or simply hand fan, is any broad, flat surface that is waved back-and-forth to create an airflow. Generally, purpose-made handheld fans are folding fans, which are shaped like a sector of a circle and made of a thin material (such as paper or feathers) mounted on slats which revolve around a pivot so that it can be closed when not in use. Hand fans were used before mechanical fans were invented. On human skin, the airflow from handfans increases evaporation which has a cooling effect due to the latent heat of evaporation of water. It also increases heat convection by displacing the warmer air produced by body heat that surrounds the skin, which has an additional cooling effect, provided that the ambient air temperature is lower than the skin temperature – which is typically about . Fans are convenient to carry around, especially folding fans. Next to the folding fan, the rigid hand screen fan was also a highly decorative and desired object among the higher cla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CB Radio
Citizens band radio (also known as CB radio), used in many countries, is a land mobile radio system, a system allowing short-distance person-to-many persons bidirectional voice communication among individuals, using two way radios operating on 40 channels near 27 MHz (11 m) in the high frequency (a.k.a. shortwave) band. Citizens band is distinct from other personal radio service allocations such as FRS, GMRS, MURS, UHF CB and the Amateur Radio Service ( "ham" radio). In many countries, CB operation does not require a license, and (unlike amateur radio) it may be used for business or personal communications. Like many other land mobile radio services, multiple radios in a local area share a single frequency channel, but only one can transmit at a time. The radio is normally in receive mode to receive transmissions of other radios on the channel; when users want to talk they press a "push to talk" button on their radio, which turns on their transmitter. Users o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is equal to one event per second. The period is the interval of time between events, so the period is the reciprocal of the frequency. For example, if a heart beats at a frequency of 120 times a minute (2 hertz), the period, —the interval at which the beats repeat—is half a second (60 seconds divided by 120 beats). Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. Definitions and units For cyclical phenomena such as oscillations, waves, or for examples of simple harmonic motion, the term ''frequency'' is defined as the number of cycles or vibrations per unit of time. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spindle (tool)
In machine tools, a spindle is a rotating axis of the machine, which often has a shaft at its heart. The shaft itself is called a spindle, but also, in shop-floor practice, the word often is used metonymically to refer to the entire rotary unit, including not only the shaft itself, but its bearings and anything attached to it (chuck, etc.). A machine tool may have several spindles, such as the headstock and tailstock spindles on a bench lathe. The main spindle is usually the biggest one. References to "the spindle" without further qualification imply the main spindle. Some machine tools that specialize in high-volume mass production have a group of 4, 6, or even more main spindles. These are called multispindle machines. For example, gang drills and many screw machines are multispindle machines. Although a bench lathe has more than one spindle (counting the tailstock), it is not called a multispindle machine; it has one main spindle. Examples of spindles include * On a la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotor
Rotor may refer to: Science and technology Engineering *Rotor (electric), the non-stationary part of an alternator or electric motor, operating with a stationary element so called the stator *Helicopter rotor, the rotary wing(s) of a rotorcraft such as a helicopter *ROTOR, a former radar project in the UK following the Second World War *Rotor (turbine), the rotor of a turbine powered by fluid pressure *Rotor (crank), a variable-angle bicycle crank *Rotor (brake), the disc of a disc brake, in U.S. terminology * Rotor (brake mechanism), a device that allows the handlebars and fork to revolve indefinitely without tangling the rear brake cable - see Detangler * Rotor (distributor), a component of the ignition system of an internal combustion engine *Pistonless rotary engine *Rotor (antenna) Computing *Rotor machine, the rotating wheels used in certain cipher machines, such as the German Enigma machine ** Rotor (Enigma machine), a rotating part of the German Enigma machine *Rotor (so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Circuit
An electrical network is an interconnection of electrical components (e.g., batteries, resistors, inductors, capacitors, switches, transistors) or a model of such an interconnection, consisting of electrical elements (e.g., voltage sources, current sources, resistances, inductances, capacitances). An electrical circuit is a network consisting of a closed loop, giving a return path for the current. Linear electrical networks, a special type consisting only of sources (voltage or current), linear lumped elements (resistors, capacitors, inductors), and linear distributed elements (transmission lines), have the property that signals are linearly superimposable. They are thus more easily analyzed, using powerful frequency domain methods such as Laplace transforms, to determine DC response, AC response, and transient response. A resistive circuit is a circuit containing only resistors and ideal current and voltage sources. Analysis of resistive circuits is less complicated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Detent
A detent is a mechanical or magnetic means to resist or arrest the movement of a mechanical device. 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. Magnetic detents are inherent in some types of electric motors, most often stepper motors. Mechanics Arresting movement Ratchet and pawl The ratchet-and- pawl design arrests movements by employing a small gravity- or spring-actuated lever paired with a notched wheel. The lever is mounted on a pivot point in proximity to the wheel. The vertical angle of the sides of the notches that face the direction that rotation is desired is generally very acute (45 degrees or less), so that as the wheel rotates in that direction, the end of the lever is easily lifted or pushed out and over the top of a notch. Following this, the lever drops into the next notch and the next et cetera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Switch
In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type of switch is an electromechanical device consisting of one or more sets of movable electrical contacts connected to external circuits. When a pair of contacts is touching current can pass between them, while when the contacts are separated no current can flow. Switches are made in many different configurations; they may have multiple sets of contacts controlled by the same knob or actuator, and the contacts may operate simultaneously, sequentially, or alternately. A switch may be operated manually, for example, a light switch or a keyboard button, or may function as a sensing element to sense the position of a machine part, liquid level, pressure, or temperature, such as a thermostat. Many specialized forms exist, such as the toggle switch, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotary System
The rotary machine switching system, or most commonly known as the rotary system, was a type of automatic telephone exchange manufactured and used primarily in Europe from the 1910s. The system was developed and tested by AT&T's American engineering division, Western Electric, in the United States, at the same time when Western Electric was also developing the Panel switch. When AT&T selected the Panel System for large American exchanges, development and sales of the ''No. 7-A Machine Switching System'', its formal commercial name, were transferred to Western Electric's international division in Belgium. In Europe and other continents the system was met with considerable commercial success. The Rotary and Panel systems were very different systems, but both used the same newly developed component technology, such as Western Electric's latest relays, and the principles of the Lorimer system of revertive pulsing and preselection. The Rotary switches were smaller than the Panel system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stepping Switch
In electrical control engineering, a stepping switch or stepping relay, also known as a uniselector, is an electromechanical device that switches an input signal path to one of several possible output paths, directed by a train of electrical pulses. The major use of stepping switches was in early automatic telephone exchanges to route telephone calls. Later, they were often used in industrial control systems. During World War II, Japanese cypher machines, known in the United States as CORAL, JADE, and PURPLE contained them. Code breakers at Bletchley Park employed uniselectors driven by a continuously rotating motor rather than a series of pulses in the Colossus to cryptanalyse the German Lorenz ciphers. In a uniselector, the stepping switch steps only along or around one axis, although several sets of contacts are often operated simultaneously. In other types, such as the Strowger switch, invented by Almon Brown Strowger in 1888, mechanical switching occurs in two directions, ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commutator (electric)
A commutator is a rotary electrical switch in certain types of electric motors and electrical generators that periodically reverses the current direction between the rotor and the external circuit. It consists of a cylinder composed of multiple metal contact segments on the rotating armature of the machine. Two or more electrical contacts called " brushes" made of a soft conductive material like carbon press against the commutator, making sliding contact with successive segments of the commutator as it rotates. The windings (coils of wire) on the armature are connected to the commutator segments. Commutators are used in direct current (DC) machines: dynamos (DC generators) and many DC motors as well as universal motors. In a motor the commutator applies electric current to the windings. By reversing the current direction in the rotating windings each half turn, a steady rotating force (torque) is produced. In a generator the commutator picks off the current generated in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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