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Hoist Controller
A hoist controller is the controller for a hoist. The term is used primarily in the context of electrically operated hoists, but it is apparent that the control systems of many 20th century steam hoists also incorporated controllers of significant complexity. Consider the control system of the Quincy Mine No. 2 Hoist. This control system included interlocks to close the throttle valve at the end of trip and to prevent opening the throttle again until the winding engine was reversed. The control system also incorporated a governor to control the speed of the hoist and indicator wheels to show the hoist operator the positions of the skips in the mine shaft. The hoist controllers for modern electric mining hoists have long included such features as automatic starting of the hoist when the weight of coal or ore in the skip reaches a set point, automatic acceleration of the hoist to full speed and automatic deceleration at the end of travel. Hoist controllers need both velocity and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Controller (control Theory)
Control theory is a field of mathematics that deals with the control of dynamical systems in engineered processes and machines. The objective is to develop a model or algorithm governing the application of system inputs to drive the system to a desired state, while minimizing any ''delay'', ''overshoot'', or ''steady-state error'' and ensuring a level of control stability; often with the aim to achieve a degree of optimality. To do this, a controller with the requisite corrective behavior is required. This controller monitors the controlled process variable (PV), and compares it with the reference or set point (SP). The difference between actual and desired value of the process variable, called the ''error'' signal, or SP-PV error, is applied as feedback to generate a control action to bring the controlled process variable to the same value as the set point. Other aspects which are also studied are controllability and observability. Control theory is used in control system eng ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hoist (device)
A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fiber or wire rope as its lifting medium. The most familiar form is an elevator, the car of which is raised and lowered by a hoist mechanism. Most hoists couple to their loads using a lifting hook. Today, there are a few governing bodies for the North American overhead hoist industry which include the Hoist Manufactures Institute, ASME, and the Occupational Safety and Health Administration. HMI is a product counsel of the Material Handling Industry of America consisting of hoist manufacturers promoting safe use of their products. Types The word “hoist” is used to describe many different types of equipment that lift and lower loads. For example, many people use “hoist” to describe an elevator. The information contained here pertains specially to overhead, cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Control System
A control system manages, commands, directs, or regulates the behavior of other devices or systems using control loops. It can range from a single home heating controller using a thermostat controlling a domestic boiler to large industrial control systems which are used for controlling processes or machines. The control systems are designed via control engineering process. For continuously modulated control, a feedback controller is used to automatically control a process or operation. The control system compares the value or status of the process variable (PV) being controlled with the desired value or setpoint (SP), and applies the difference as a control signal to bring the process variable output of the plant to the same value as the setpoint. For sequential and combinational logic, software logic, such as in a programmable logic controller, is used. Open-loop and closed-loop control There are two common classes of control action: open loop and closed loop. In an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quincy Mine
The Quincy Mine is an extensive set of copper mines located near Hancock, Michigan. The mine was owned by the Quincy Mining Company and operated between 1846 and 1945, although some activities continued through the 1970s. The Quincy Mine was known as "Old Reliable," as the Quincy Mine Company paid a dividend to investors every year from 1868 through 1920. The Quincy Mining Company Historic District is a United States National Historic Landmark District; and other Quincy Mine properties nearby, including the Quincy Mining Company Stamp Mills, the Quincy Dredge Number Two, and the Quincy Smelter are also historically significant. Lifespan: 1846-1945 The Quincy Mine was founded in 1846 by the merger of the Northwest Mining Company and the Portage Mining Company. Due to poor communication between government offices, these two speculative mining companies had purchased the same tracts of land during the mining rush of the early 1840s. The directors met and decided to merg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Throttle
A throttle is the mechanism by which fluid flow is managed by constriction or obstruction. An engine's power can be increased or decreased by the restriction of inlet gases (by the use of a throttle), but usually decreased. The term ''throttle'' has come to refer, informally, to any mechanism by which the power or speed of an engine is regulated, such as a car's accelerator pedal. What is often termed a ''throttle'' (in an aviation context) is also called a thrust lever, particularly for jet engine powered aircraft. For a steam locomotive, the valve which controls the steam is known as the regulator. Internal combustion engines In an internal combustion engine, the throttle is a means of controlling an engine's power by regulating the amount of fuel or air entering the engine. In a motor vehicle the control used by the driver to regulate power is sometimes called the throttle, accelerator, or gas Automobile pedal, pedal. For a gasoline engine, the throttle most commonly regul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Winding Engine
A winding engine is a stationary engine used to control a cable, for example to power a mining hoist at a pit head. Electric hoist controllers have replaced proper winding engines in modern mining, but use electric motors that are also traditionally referred to as ''winding engines''. Early winding engines were hand, or more usually horse powered. The first powered winding engines were stationary steam engines. The demand for winding engines was one factor that drove James Watt to develop his rotative beam engine, with its ability continuously to turn a winding drum, rather than the early reciprocating beam engines that were only useful for working pumps. They differ from most other stationary steam engines in that, like a steam locomotive, they need to be able to stop frequently and also reverse. This requires more complex valve gear and other controls than are needed on engines used in mills or to drive pump A pump is a device that moves fluids (liquids or gases), or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centrifugal Governor
A centrifugal governor is a specific type of governor with a feedback system that controls the speed of an engine by regulating the flow of fuel or working fluid, so as to maintain a near-constant speed. It uses the principle of proportional control. Centrifugal governors, also known as "centrifugal regulators" and "fly-ball governors", were invented by Christiaan Huygens and used to regulate the distance and pressure between millstones in windmills in the 17th century. In 1788, James Watt adapted one to control his steam engine where it regulates the admission of steam into the cylinder(s), a development that proved so important he is sometimes called the inventor. Centrifugal governors' widest use was on steam engines during the Steam Age in the 19th century. They are also found on stationary internal combustion engines and variously fueled turbines, and in some modern striking clocks. A simple governor does not maintain an exact speed but a speed range, since under increasi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skip (container)
A skip (or skip bin) is a large open-topped waste container designed for loading onto a special type of lorry. Typically skip bins have a distinctive shape: the longitudinal cross-section of the skip bin is either a trapezium or two stacked trapezia. The lower trapezium has the smaller edge at the bottom of the skip bin, and a longer edge at the top. The smaller edge on either end is lower which makes it easier to load. Where there is an upper trapezium, it has the smaller edge at the top. There is a sloping floor or wall at each end. There are usually two lugs on each side of the bin onto which chains can be attached, permitting the heavy skip bin to be lifted onto and off a skip lorry or skip truck. A special skip-carrying lorry or crane is used. One end of the skip sometimes has a large door that hinges down to allow manual loading and unloading, these skips are called 'drop-door skips'. Skips are usually durable and tough, made to withstand rough use by tradespeople and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shaft Mining
Shaft mining or shaft sinking is the action of excavating a mine shaft from the top down, where there is initially no access to the bottom. Shaft (civil engineering), Shallow shafts, typically sunk for civil engineering projects, differ greatly in execution method from deep shafts, typically sunk for mining projects. Shaft sinking is one of the most difficult of all mine development methods: restricted space, gravity, groundwater and specialized procedures make the task quite formidable. Shafts may be sunk by conventional drill and blast or mechanised means. Historically, mine shaft sinking has been among the most dangerous of all the mining occupations and the preserve of mining contractors called sinker (mining), sinkers. Today shaft sinking contractors are concentrated in Canada, Germany, China and South Africa. The modern shaft sinking industry is gradually shifting further towards greater mechanisation. Recent innovations in the form of full-face shaft boring (akin to a v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hoist (mining)
In underground mining a hoist or winder is used to raise and lower conveyances within the mine shaft. Modern hoists are normally powered using electric motors, historically with direct current drives utilizing Ward Leonard control machines and later solid-state converters (thyristors), however modern large hoists use alternating current drives that are variable frequency controlled. There are three principal types of hoists used in mining applications: Drum hoist Drum hoists are the most common type of hoist used in North America, South Africa and South America. When using a drum hoist the hoisting cable is wound around the drum when the conveyance is lifted. Single-drum hoists can be used in smaller applications, however double-drum hoists easily allow the hoisting of two conveyances in balance (i.e. one skip being lifted while a second skip is being lowered). Drum hoists are mounted on concrete slabs within a hoistroom, the hoisting ropes run from the drum, up to the top ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analogue Electronics
Analogue electronics ( en-US, analog electronics) are electronic systems with a continuously variable signal, in contrast to digital electronics where signals usually take only two levels. The term "analogue" describes the proportional relationship between a signal and a voltage or current that represents the signal. The word analogue is derived from the el, word ανάλογος (analogos) meaning "proportional". Analogue signals An analogue signal uses some attribute of the medium to convey the signal's information. For example, an aneroid barometer uses the angular position of a needle as the signal to convey the information of changes in atmospheric pressure. Electrical signals may represent information by changing their voltage, current, frequency, or total charge. Information is converted from some other physical form (such as sound, light, temperature, pressure, position) to an electrical signal by a transducer which converts one type of energy into another (e.g. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydraulic Hooklift Hoist
Hydraulic hooklift hoists are mounted on heavy duty trucks to enable hauliers to change out flatbeds, dumpster bodies, and similar containers. Primarily used in conjunction with tilt frame bodies and specialised roller containers, generally designed for the transportation of materials in the waste, recycling, scrap and demolition industries, as well as for disposal of construction debris. The system employs a series of hydraulic rams to hook, lift and hoist the container onto the chassis of the truck. There are several configuration options, and strict guidelinesOffice of the Federal Register (U.S.) (2010) ''Code of Federal Regulations, Title 49, Transportation, Pt. 300-399, Revised as of October 1, 2009'p.475.Government Printing Office. . Retrieved August 2011 which must be followed to ensure that the container is secured on the truck in transit. Load capacity Lift and dump capacities of hydraulic hooklift hoists typically range from . Generally a hoist is capable of lift ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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