3000W Chinese Gensets Info.
professor95 wrote: EDIT ADDED 45/5/2013- When this thread started in March of 2005, I never expected to see it survive this long or amass the quantity of information that has been shared here. In...
Forum Discussion
Specifications without all the little qualifiers (details) are at best vague and at worst, a total lie. A noise measurement needs to detail
WHAT is being measured (each side of a genset "sounds" different).
DISTANCE it's being measured from (sound intensity drops rapidly with distance).
SCALE it's measured on (dba, b, c--each "weighs", or biases the measurement according to the frequency range of interest)
SURROUNDINGS--rarely mentioned but the intensity will be very different, at some distance, when measured in the middle of a grassy field compared to a cement parking lot due to absorbed/reflected sound reaching the microphone.
There are various standards groups that specify these parameters in an attempt to make everyone use the same methods. An example would be "Noise output measured 68dba at 7M from the muffler, free field (meaning no nearby reflecting surfaces), engine at idle". Now that's useful.
Generator distributors should undertake these measurements themselves if the manufacturer can't or won't provide them. WIthout these details an unscrupulous seller could claim theirs measured "40db" of noise. It would be helpful to know it wasn't actually running at the time!
Sorry for the length of my rant--but it's my (day) job :B
WHAT is being measured (each side of a genset "sounds" different).
DISTANCE it's being measured from (sound intensity drops rapidly with distance).
SCALE it's measured on (dba, b, c--each "weighs", or biases the measurement according to the frequency range of interest)
SURROUNDINGS--rarely mentioned but the intensity will be very different, at some distance, when measured in the middle of a grassy field compared to a cement parking lot due to absorbed/reflected sound reaching the microphone.
There are various standards groups that specify these parameters in an attempt to make everyone use the same methods. An example would be "Noise output measured 68dba at 7M from the muffler, free field (meaning no nearby reflecting surfaces), engine at idle". Now that's useful.
Generator distributors should undertake these measurements themselves if the manufacturer can't or won't provide them. WIthout these details an unscrupulous seller could claim theirs measured "40db" of noise. It would be helpful to know it wasn't actually running at the time!
Sorry for the length of my rant--but it's my (day) job :B
