Practical Speed-Measuring Devices for High Speed Centrifuges

Abstract

The first device described is a direct-reading stroboscope of the slotted-device type in which the device is driven through a variable-ratio friction drive from a synchronous motor. A stop watch and revolution counter built into the assembly provide the speed measurement. It is claimed that this type of drive is superior to the conventional variable-speed D. C. motor drive with respect to the constancy of the stroboscopic frequency. The record device is an assembly, also driven by a synchronous motor, which provides 52 fixed frequencies in the range 3000-70,000 v. p. m. A convenient, flexible multiple cam arrangement for automatic photographic recording of sedimentation at predetd. times is built into this device. Both devices are described sufficiently completely to permit construction without further information.