- Non-contact speed measurement
- High intensity flashes
- Direct speed reading in RPM
- No shaft modification
Measurement of the speed of a rotating shaft
is a common requirement in many industrial and laboratory
applications. Such measurements have usually been carried
out in the past with the help of contact type tachometers
with friction drive. More recently digital optical non-contact
tachometers have been designed which count the reflected pulses
from a white patch on the shaft and then display the speed
in rpm. The light source is usually a filament lamp operating
with dry cells leading to limited life and illumination. A
similar idea with magnetic pick-up from a particular area
of the shaft has also been used for speed measurement.
A third category of speed measurement instruments
is based on the stroboscope principle. In this a high intensity
light flash of a variable frequency is directed towards rotating
shaft. Any marking on the shaft appears stationary, if the
time of one shaft revolution is a multiple of the flash period.
Earlier stroboscopes used neon tubes of low intensity which
forced their use close to the rotating shaft.
The present unit has been designed to remove
most of the above shortcomings. This has resulted in a good
quality, convenient-to-use, direct reading speed measuring
instrument. A highly stable function generator IC based circuit
provides the basic variable frequency timing pulses. These
are read on an IC based 4-digit speed display in rpm. The
flasher unit generates the high intensity flashes at a suitably
scaled rate directed towards the rotating shaft. A 10 turn
potentiometer makes the task of speed setting very precise.
Operating instructions are included in the Instruction manual
accompanying the unit.
Features & Specifications
- Non-Contact-type - no error due to friction
drive, suitable for small motors and also motors in inaccessible
- High intensity XENON flashes - operation
possible from a reasonable distance (0.5m) in usual ambient
light in a room. Detachable lamp unit with 1.5m cable
- 4-digit speed display in rpm - operating
range of 500-9900 rpm, resolution 1 rpm. High accuracy crystal
controlled LED display
- No shaft modification - Any distinctive
existing shaft marking may be used.
- Alternatively use of stickers or markers
- Power - 220V±10%, 50Hz mains operation
- IC regulated internal supplies