Measurement of frequency of rotation of various mechanisms is performed by means of tachometers, tacho generators with voltmeters, frequency meters, stroboscopes and measuring instruments of linear speed. The first of these devices allows to receive result directly, the others - after simple recalculation of indications.
It is required to you
- Rotation frequency sensor
- Tachometer
- Frequency meter
- The tacho generator with the voltmeter
- Stroboscope
- Felt-tip pen
- Measuring instrument of linear speed
Instruction
1. Use of the tachometer - the most rational way of measurement of frequency of rotation. It is applicable concerning the mechanisms equipped with sensors of frequency of rotation or allowing installation of such sensors. If the sensor is not installed yet, install it at the stopped mechanism. Connect the tachometer, compatible to it, to the sensor. If the sensor demands food, but it moves not from the tachometer, and from a separate source, connect it. Only then start the mechanism and wait until it is untwisted. On the indicator of the tachometer read result.
2. It happens so that the mechanism is equipped with the rotation frequency sensor, but there is no suitable tachometer, but there is a frequency meter. It is possible to perform measurement and in this case. Give an external power supply on the sensor, and instead of the tachometer connect a frequency meter. Calculate the frequency of rotation on the following formula: ω=(f*60)/n, where ω - the frequency of rotation, rpm, f - indications of a frequency meter, Hz, n - quantity of the impulses developed by the sensor for one turn.
3. If the mechanism is equipped with the tacho generator or allows its installation, measure the frequency of rotation so. If the tacho generator is not installed yet, install it at the stopped mechanism. Connect the voltmeter to the tacho generator and if it is necessary, an excitement tension source. Start the mechanism and after an exit it on an operating mode measure tension developed by the tacho generator. Count it in rotation frequency, being guided by the schedule or a formula from the instruction to the tacho generator.
4. Measurement of frequency of rotation by the stroboscope is carried out in the contactless way. At the stopped mechanism apply on that its detail which frequency of rotation needs to be measured with a felt-tip pen a tag. Start the mechanism and let's it be untwisted. Direct the stroboscope to the rotating detail then the regulator of frequency of flashes achieve that the tag seemed motionless. The regulator scale at the stroboscope usually has graduation with impulses in a minute - in this case recalculation will not be required. If it has graduation in hertz, increase indications by 60.
5. The measuring instrument of linear speed has a rubber roller which is pressed to a smooth surface of the rotating shaft. Pressing of a roller to the surfaces which are not smooth, inadmissibly. Having measured linear speed, count it in rotation frequency on a formula: ω=(v*60) / (π * (D/1000)), where ω - the frequency of rotation, rpm, v - the measured linear speed, m/s, D - diameter of a shaft, mm
6. If the frequency of rotation of one link of the mechanism is measured, and it is necessary to find the frequency of rotation of other link related through transfer of any given sort, recalculation is carried out, being guided by the transfer relation of this transfer.
7. Frequency of rotation of some mechanisms can be found, without resorting to use of any additional devices as all necessary for this purpose is already available in the device which part is the mechanism. So, if the tachometer of the computer fan is attached to the computer motherboard, it is possible to determine the frequency of its rotation, having entered the CMOS Setup mode and having selected the PC Health Status item in the menu. In the vehicle equipped with the tachometer it is possible to learn at any time without any extras the frequency of rotation of the crankshaft of the engine.