How to Measure the Noise of Diesel Generator set

Diesel generator set noise measuring instruments usually measure the sound pressure level, the unit is dB, the data measured by the general noise meter is the instantaneous sound pressure level including the maximum and minimum values, and the integral function can also be added to measure the effective value for a period of time. When measuring the noise of a diesel generator set, it is generally necessary to measure the total sound pressure level of the noise and the frequency characteristic of the sound pressure level. The main instruments used are: sound level meter, frequency analyzer, level recorder, tape recorder and octave filters, etc.

Sound level meter

The sound level meter is the most commonly used portable instrument for noise measurement. It can measure the total vocal level and various weighted vocal levels. The commonly used sound level meters can be divided into ordinary sound level meters and precision level meters according to their accuracy.

• How the sound level meter works

The sound level meter is composed of a microphone, an amplifier, a bright subtractor, a weighting network, a detection and a display, etc. The preamplifier is used for bright reactance conversion, and the subtractor is used for range switching. This sound level meter has A, B, C Three kinds of weighting networks, which can be used in conjunction with spectrum analyzers, level recorders and displays, etc., to comprehensively analyze the spectrum characteristics of noise sources. weighting network. After the weighting network is determined, first pass the noise with the lowest frequency through the frequency borrower, and then check whether the attenuation coefficient is correct. If it is correct, measure the sound pressure value of this frequency noise, and then measure the sound pressure value of other frequency noise. Until the noise of each octave center frequency is measured and the sound pressure levels are calculated, the average sound pressure level is finally calculated.

• microphones

The microphone is a sensor that realizes the conversion of sound and electricity, and there are electric, electronic, and capacitive types. The work of the electrodynamic microphone is: under the action of the vocal music, the dynamic black in the magnetic field will vibrate with the change of the vocal music; the induced electromotive force is characterized by low output resistance and little influence by temperature, but low sensitivity and great interference by the magnetic field , mostly used in ordinary sound level meters. The music electric microphone is based on the music electricity effect of some electric materials, which converts the change of vocal music into electric charge or electric signal output. Its structure is simple, its price is cheap, and its dynamic range is wide, but its sensitivity is low and it is greatly affected by temperature. It is often used in ordinary sound level meters.

Spectrum Analyzer

The frequency and harmonic analysis instrument is an instrument for studying the spectrum structure of the electrical signal of a diesel generator set. It is used to measure signal parameters such as signal distortion, modulation degree, spectral purity, frequency stability and intermodulation distortion. It can be used to measure circuit systems such as amplifiers and filters. Certain parameters, is a multipurpose electronic measuring instrument. It can also be called frequency domain oscilloscope, tracking oscilloscope, analytical oscilloscope, harmonic analysis dew, frequency characteristic analyzer or Beaulieu analyzer, etc. Modern spectrum analyzers can display analysis results in analog or digital ways, and can analyze electrical signals in all radio frequency bands from very low frequencies below 1 Hz to subroom meter bands. If digital circuits and microprocessors are used inside the instrument, it has storage and Computing function: configure standard interface, it is easy to form an automatic test system

level recorder

The level recorder can automatically record the measurement results. The sound level meter cooperates with the level recorder to measure and record the distribution of star sound over time, and then cooperate with octave or 1/3-octave whisker , can directly record entertainment sound

spectrum. The level recorder can record frequency response characteristics, reverberation decay curve, etc. In the vibration and shock measurement, the recording instruments used more in the past include level recorder, X-Y recorder, light oscilloscope and Zigzag recorder, etc. At present, many new X-Y recorders have the function of level recording, but the current voltage-controlled oscillator frequency slider has no rotating parts, so the production and use of level recorders are gradually reduced. The X-Y recorder will continue to be used in frequency response characteristic measurement and modal analysis. The direct pen recorder is not suitable for alarm measurement, because with the development of other recording and display instruments, and because the light oscilloscope does not make accurate processing of the recorded signal, the application of the light oscilloscope will gradually decrease, and now there is only on-site exposure display Waveform ultraviolet oscilloscopes are widely used.
In the future, tape recorders will still be used for on-site measurement and large-scale data recording of diesel generator sets. Transient signal measurement and signals that need to be processed in time will be recorded by the digital recorder, and the digital recorder will appear in two combinations, that is, a digital storage oscilloscope that integrates data recording and display: a data recording, analysis and display. Dynamic signal analyzer, digital recorder plus computer for user development.

Acoustic collection is an unavoidable phenomenon in modern society, which may affect people’s health and normal life. The sound exposure monitor is an instrument widely used in accounting environment monitoring. It Sound can be monitored and analyzed in real time. It can be used to detect environmental pollution caused by noise and protect people’s health. It can also be used to test the effect of noise control in diesel generator rooms. The use of noise monitors can provide accurate and reliable noise decibel values to help users control power generation Whether the computer room can effectively control noise pollution provides a reliable reference, and provides data support for the later sound insulation peak engineering design and construction plan. In the future, the noise monitor will play a greater role and become an important tool in the environment. It plays an important role in monitoring and environmental protection.