and engineering journal . ted together to form a com-pact, totally enclosed, weather and mistake-proof switch-board which safely withstands the roughest use. Thebreakers are bolted to a steel-plate chamber which containsthe isolating switches and bus-bars, and carries the necessary-instruments. Interlocking devices are provided between theisolating switches and the breakers. The illustration showsa seven-unit switchboard which was installed in a mill tocontrol a group of five slip-ring motors, each driving a sectionof the mill. An oil-cooled rotor starter is included in eachunit, mec
and engineering journal . ted together to form a com-pact, totally enclosed, weather and mistake-proof switch-board which safely withstands the roughest use. Thebreakers are bolted to a steel-plate chamber which containsthe isolating switches and bus-bars, and carries the necessary-instruments. Interlocking devices are provided between theisolating switches and the breakers. The illustration showsa seven-unit switchboard which was installed in a mill tocontrol a group of five slip-ring motors, each driving a sectionof the mill. An oil-cooled rotor starter is included in eachunit, mechanically interlocked with its circuit breaker. Allthe units are electrically interlocked to ensure that the varioussections are started up in correct sequence, and if one sectionis stopped, the others dependent on it are automatically shutdown. Many of these switchboards have been installed inmines, where they have been subjected to very hard wearand tear, and have withstood falls of roof without causinginterruption of the patented design, adjustable for wear, and with renewabletips. The ari shields are effective and magnetic blow-outsare fitted to the pattern. The illustration shows a with cover removed and arc shields and blow-outswithdrawn for inspection. The contact fingers are disposedradially to the barrel and have roller tips, which are pressedon to ihe barrel contacts by spring. Tins design is a depar-ture from existing types and has several advantages. Theroller is mounted so that it can rotate, oscillate and lift, andconsequently beds perfectly on the segment. Tin- barrelcontacts are shaped to prevent the possibility of an arc beingblown inwards and spreading from finger to finger, a troublewhich is sometimes present with a magnetic blow-out fieldparallel to the barrel. The handle lever is very strong andfitted with a device shaped to set itself correctly, so that nomatter how the handle is left, it always comes to the rightposition ti>
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License: Licensed
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Keywords: ., bo, bookcentury1800, bookdecade1890, booksubjectmineralindustries
