SOUND POWER LEVEL EMITTED BY AGRICULTURAL TRACTOR UNDER STATIC AND DINAMIC CONDITIONS

Abstract

The noise produced by farm machinery may cause hearing problems to its operators along the time. The objective of this study was to evaluate the sound power level emitted by agricultural tractor under static and dynamic conditions, in relation to the IEC651 and IEC61672 norms. It was conducted at the Universidade Federal do Vale do São Francisco, in Petrolina, Pernambuco State, Brazil, in 2009, by using a Valtra 785 TDA tractor without cabin and equipment to measure its sound power level. The measurements were: static (anterior, posterior, right, and left positions, in relation to the operator’s seat, for each meter along the maximum distance of 10 m, and different engine rotation speeds, with two measuring devices) and dynamic (five speeds on concrete and soil test tracks, with two devices). Two measurement devices were used to evaluate the sound power level. For the devices in accordance with the IEC651 and IEC62672 norms, the second one always presented higher sound power levels, due to the fact that the first one was equipped with a wind protector. In all positions, the sound power level was higher than allowed by law. As the engine rotation speed increases, the sound power level also increases. It was noticed that both test tracks can be used for sound power level analysis, due to their similar results. The tractor speed affected its sound power level, with higher values for longer gears.

KEY-WORDS: Noise; ergonomics; agricultural mechanization.