How to use a Treysit Sirometer
Using a Treysit Sirometer is very simple.
Place it tightly on the outside case of the running motor.
By turning the top part of the Sirometer it emits a piece of wire. When the wire is in resonance with the vibrations of the machine it will show it by vibration. When the wire reaches the resonance point the RPM and frequency can be read. The upper scale shows RPM and the lower scale shows cycles per second. To get used to it try it on a motor with known RPM and adjust the Sirometer to the scale. Reduction gears show a misreading.
Please note: Gas motors give the RPM of the crankshaft but other fast running shafts may influence the reading.
After using the Sirometer a few times taking RPM reading will be easy. If the top part has turned heavy after having been used for a time, put a drop of thin oil into the brass-wire-loop, after the brass-wire has been turned out.
800-50 000 rpm
14-750 cycles per second.