On Speed Indicators for Hoisting Machines
Abstract Generated abstract
The paper discusses the need to replace mercury-float speed meters used on Soviet mine hoisting installations, focusing on their inadequate recording scale, operational unreliability, and high cost. It reviews practical shortcomings of instruments made by Karlik, Logan, and the Tomsk Manometer Plant, including poor interpretability of speed diagrams, mercury evaporation, and belt slip. The author argues that an electric self-recording speed meter, using a tachogenerator already present in hoisting installations, should be developed to provide more reliable and economical monitoring of hoisting machine control quality.
Full Text
On Speed Meters for Mine Hoisting Machines
V. D. Petunov
(Presented by the scientific seminar of the Department of Mining Mechanics)
Many mercury-float-type speed meters made by the firms “Karlik,” “Logan,” and by the Tomsk Manometer Plant have been installed on the hoisting installations of mines in the Soviet Union. The speed meters are intended for measuring and recording the speed of motion of hoisting conveyances as a function of time.
The main shortcomings of the indicated speed meters are:
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From the records produced by the instruments it is impossible to judge the operating regime of the hoisting machine, since the speed diagram is recorded on a very small scale. The speed scale is 1.10 m/sec per 1 mm, and the time scale is 0.075 sec/mm, with a diagram-line thickness of 0.5–0.8 mm.
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Many components of the instrument are unreliable in operation. For example, the mercury in the three-tube vessel and in the contact cups can evaporate, and it must be replenished periodically. The system of drive belts and pulleys slips when even a small amount of oil gets on it.
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The instrument is expensive. A speed meter from the Tomsk Manometer Plant costs 5,520 rubles.
Taking into account the unreliability in operation of mercury-float-type instruments and their high cost, it is necessary to develop the design of an electric mine speed meter in such a way that, from its speed diagram, it would be possible to monitor the quality of control of the hoisting machine. The sensor for such a self-recording electric instrument may be a tachogenerator, which is usually installed on the hoisting installation for connecting the protection circuits.
The development of a reliable and inexpensive electric speed meter that eliminates the shortcomings of mercury speed meters is a highly pressing issue in the operation and monitoring of mine hoisting machines.