Hoist controller
Encyclopedia
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 absolute position references taken, typically taken from the winding drum of the hoist. Modern hoist controllers replace many of the mechanical analog
mechanisms of earlier controllers with digital control systems.
Controller (control theory)
In control theory, a controller is a device which monitors and affects the operational conditions of a given dynamical system. The operational conditions are typically referred to as output variables of the system which can be affected by adjusting certain input variables...
for a hoist
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 load is attached to the hoist by means of a...
. 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
Control system
A control system is a device, or set of devices to manage, command, direct or regulate the behavior of other devices or system.There are two common classes of control systems, with many variations and combinations: logic or sequential controls, and feedback or linear controls...
of the Quincy Mine
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...
No. 2 Hoist. This control system included interlocks to close the throttle
Throttle
A throttle is the mechanism by which the flow of a fluid is managed by constriction or obstruction. An engine's power can be increased or decreased by the restriction of inlet gases , but usually decreased. The term throttle has come to refer, informally and incorrectly, to any mechanism by which...
valve at the end of trip and to prevent opening the throttle again until the winding engine
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.Most proper...
was reversed. The control system also incorporated a governor
Centrifugal governor
A centrifugal governor is a specific type of governor that controls the speed of an engine by regulating the amount of fuel admitted, so as to maintain a near constant speed whatever the load or fuel supply conditions...
to control the speed of the hoist and indicator wheels to show the hoist operator the positions of the skips
Skip (container)
A rubbish skip is usually called merely a skip or waste bin. A skip is a large open-topped container designed for loading onto a special type of lorry. Differing from dumpster, instead of being emptied into a waste vehicle onsite, a skip is replaced by an empty skip and then tipped at a landfill...
in the mine shaft.
The hoist controllers for modern electric mining hoists
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 solid-state converters , however modern large hoists utilize alternating current drives...
have long included such features as automatic starting of the hoist when the weight of coal or ore in the skip
Skip (container)
A rubbish skip is usually called merely a skip or waste bin. A skip is a large open-topped container designed for loading onto a special type of lorry. Differing from dumpster, instead of being emptied into a waste vehicle onsite, a skip is replaced by an empty skip and then tipped at a landfill...
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 absolute position references taken, typically taken from the winding drum of the hoist. Modern hoist controllers replace many of the mechanical analog
Analogue electronics
Analogue electronics are electronic systems with a continuously variable signal, in contrast to digital electronics where signals usually take only two different levels. The term "analogue" describes the proportional relationship between a signal and a voltage or current that represents the signal...
mechanisms of earlier controllers with digital control systems.