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Rpm meter
Page 65
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Known as the Treysit Sirometer, a device evolved by Industrial Power Units Ltd is claimed to enable engine speeds to be read quickly and accurately by transforming vibrations into rpm.
The instrument is placed on any convenient part of the engine while it is running, and by rotating its dial • a vibrating wire is adjusted until its point of maximum amplitude is reached. It is then in resonance with the vibrations of the engine, and rpm can be read direct from its scale.
Its useful range is from 800 to 8000 rpm but speeds up to 50,000 rpm can be checked. A typical application is reading maximum engine speeds when setting variable speed governors and fuel stops on commercial vehicle diesel engines. Made by: Industrial Power Units Ltd, Vane St, Wolverhampton. WV2 1AD.