Metadyne
Encyclopedia
A Metadyne is an electrical machine with three, or more, brushes
. It can be used as an amplifier
or rotary transformer
. It is similar to a third brush dynamo but much more complex, having additional regulator or "variator" windings. It is also similar to an amplidyne
except that the latter has a compensating winding. The technical description is "a cross-field direct current
machine designed to utilize armature
reaction". A metadyne can convert a constant-voltage
input into a constant current
, variable voltage, output.
and for speed control in electric train
s, e.g. London Underground O Stock
. The equipment in the latter case weighed three tons. They have been superseded by solid state
devices.
The concept and original patents were issued to the Macfarlane engineering company of Cathcart, Scotland. They were licensed to 'Met Vick' (Metropolitan-Vickers
) and there was a cross licence or some form of agreement with GE USA who patented almost to the day the 'Amplidyne' which works the same way (the difference is simply in the amount of compensation that is made for armature reaction). Macfarlane used the concept in two main applications: constant current for electric welders and, in Amplidyne form, for alternator voltage and current control.
in 1928. However, machines similar to the metadyne had been experimented with much earlier, e.g. by Rosenberg in 1904. British patent
number 26,607 of 1907 by Felton and Guilleaume also refers to a similar machine. Development work at Metropolitan-Vickers
in the 1930s was led by Arnold Tustin
.
Brush (electric)
A brush is a device which conducts current between stationary wires and moving parts, most commonly in a rotating shaft. Typical applications include electric motors, alternators and electric generators.-Etymology:...
. It can be used as an amplifier
Amplifier
Generally, an amplifier or simply amp, is a device for increasing the power of a signal.In popular use, the term usually describes an electronic amplifier, in which the input "signal" is usually a voltage or a current. In audio applications, amplifiers drive the loudspeakers used in PA systems to...
or rotary transformer
Rotary transformer
A rotary transformer is a specialized transformer used to couple electrical signals between two parts which rotate in relation to each other....
. It is similar to a third brush dynamo but much more complex, having additional regulator or "variator" windings. It is also similar to an amplidyne
Amplidyne
An amplidyne is an electromechanical amplifier invented during World War II by Ernst Alexanderson. It is usually an AC motor driving a DC generator with modifications to increase the power gain available...
except that the latter has a compensating winding. The technical description is "a cross-field direct current
Direct current
Direct current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...
machine designed to utilize armature
Armature (electrical engineering)
In electrical engineering, an armature generally refers to one of the two principal electrical components of an electromechanical machine–generally in a motor or generator, but it may also mean the pole piece of a permanent magnet or electromagnet, or the moving iron part of a solenoid or relay....
reaction". A metadyne can convert a constant-voltage
Voltage
Voltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
input into a constant current
Electric current
Electric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
, variable voltage, output.
Uses
Metadynes have been used to control the aiming of large gunsArtillery
Originally applied to any group of infantry primarily armed with projectile weapons, artillery has over time become limited in meaning to refer only to those engines of war that operate by projection of munitions far beyond the range of effect of personal weapons...
and for speed control in electric train
Electric train
Electric train may refer to:* Diesel-electric locomotive...
s, e.g. London Underground O Stock
London Underground O Stock
The O and P Stock was built for the Metropolitan Line and Hammersmith & City Line in 1937–1940 by Gloucester RC&W and Birmingham RC&W. In all there were 262 driving motors and 103 trailers...
. The equipment in the latter case weighed three tons. They have been superseded by solid state
Solid state (electronics)
Solid-state electronics are those circuits or devices built entirely from solid materials and in which the electrons, or other charge carriers, are confined entirely within the solid material...
devices.
The concept and original patents were issued to the Macfarlane engineering company of Cathcart, Scotland. They were licensed to 'Met Vick' (Metropolitan-Vickers
Metropolitan-Vickers
Metropolitan-Vickers, Metrovick, or Metrovicks, was a British heavy electrical engineering company of the early-to-mid 20th century formerly known as British Westinghouse. Highly diversified, they were particularly well known for their industrial electrical equipment such as generators, steam...
) and there was a cross licence or some form of agreement with GE USA who patented almost to the day the 'Amplidyne' which works the same way (the difference is simply in the amount of compensation that is made for armature reaction). Macfarlane used the concept in two main applications: constant current for electric welders and, in Amplidyne form, for alternator voltage and current control.
History
The history of the metadyne is very complex. The name is believed to have been coined by Pestarini in a paper which he submitted to the Montefiore International Contest at Liège, BelgiumBelgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
in 1928. However, machines similar to the metadyne had been experimented with much earlier, e.g. by Rosenberg in 1904. British patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
number 26,607 of 1907 by Felton and Guilleaume also refers to a similar machine. Development work at Metropolitan-Vickers
Metropolitan-Vickers
Metropolitan-Vickers, Metrovick, or Metrovicks, was a British heavy electrical engineering company of the early-to-mid 20th century formerly known as British Westinghouse. Highly diversified, they were particularly well known for their industrial electrical equipment such as generators, steam...
in the 1930s was led by Arnold Tustin
Arnold Tustin
Arnold Tustin, , was a British engineer, and Professor of Engineering at the University of Birmingham and at Imperial College London, who made important contributions to the development of control engineering and its application to electrical machines.- Biography :Arnold Tustin was born in 1899...
.