Comparisons between battery chainsaws and internal combustion engine chainsaws: performance and safety

Abstract

The thesis compares the features and performance of three of battery chainsaw models of two Manufacturers against two equipped with internal combustion engine and all designed for use in pruning. The cutting times for five woody species with different hardness of the wood have been examined; assessed the safety in use of the individual machines and a rough evaluation for the energy consumption. The purpose is to understand the potential of these battery chainsaws, currently used for pruning, for possible use in forest exploitation.

Dynamic analysis of centrifugal separator in unsteady-state condition with and without variable-frequency drive

“…The input of the data (Tab. 2) in equations (9), (11), (13) and (16), provides the starting time in the three cases: asynchronous standard motor with gear-box, asynchronous motor with VFD and no overload and motor with VFD and overload. Figure 5 shows the results obtained.…”

“…Finally, equations (13) and (16), obtained from the dynamical analysis in unsteady-state condition for the motor with the VFD in overload, allowed to correlate the starting time with the rated power of the electric motor. Figure 6 shows the starting time vs. the rated power and indicates the maintaining of starting time in about 10 min, as accepted by the industrial community, corresponding to halving of motor power compared to the traditional system, with a further advantage on the reduction of investment costs.…”

“…The time required in the starting phase of the centrifugal separator is another aspect that must be considered. In fact, the high inertia of the rotating parts and the high rotation speed would require the use of a very powerful electric motor [16] to make the starting phase rapid. To avoid over-sizing of the electric motor, a greater acceleration time is accepted.…”

Determining Noise and Vibration Exposure in Conifer Cross-Cutting Operations by Using Li-Ion Batteries and Electric Chainsaws

“…The few studies available at present [38,48] have made comparisons between electric and traditional endothermic chainsaws and the results have clearly shown lower emissions of both vibrations and noise in electric chainsaws than in the others, but these cannot be used in the same operations. In forest conditions, wired chainsaws are obviously inappropriate due to their need of an electric connection, while battery chainsaws can be used in specific operations only, such as delimbing and the cross-cutting of small-diameter trees, but not in felling and the processing of medium and large diameter trees.…”

“…Moreover, Lithium-ion batteries could now be recycled with an efficiency of 97% w/w of the valuable battery active materials [46,47]. In the only accessible previous study on chainsaws powered by alternative sources [38,48], it was established that the use of battery-powered chainsaws may decrease the exposure to noise and onset of HAV when compared with the use of petrol chainsaws. No recent studies have focused their attention on noise and vibration exposure by wired electric chainsaws in comparison to Li-Ion batteries models.In order to fill the gap in knowledge and to have a comprehensive framework on the exposure of workers to vibrations, field surveys during the cross-cutting operations of conifer logs with chainsaws were carried out in Central Italy.…”