As one of the first manufacturers of electric drives, Keestrack recognized the cost and energy saving potentials and operational advantages of electric power for track-mounted mobile processing solutions.
In 2012, Keestrack introduced the first diesel-electric classifier, followed in 2013 by the first hybrid scalper, crushers with electrified conveyors and electric crusher drives.
In these plants, generators ensure low engine speed resulting in fuel-saving operations of the onboard diesels.
Downstream screening plants or stockpile conveyors can now be fed via external plug-out supplies, which further improves the total fuel consumption of production trains.
As well, the installation of electrical pumps for essential hydraulic consumers — like lifting cylinders or track drives — allow the full-electric operation of today’s e-versions.
Compared to conventional diesel-hydraulic systems, energy costs can be reduced up to 80 per cent and the noise levels during emission-free plug-in operation may be reduced by 30 per cent, according to Keestrack.
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Replacing hydraulic drives on conveyors, screen shafts, compressors or water pumps with electric motors also avoids long oil piping with leak-prone hose connections. As well, thermal problems in operations under extreme conditions are eliminated.
In full-electric operation, this also applies to lubricants, filters and other wear parts of the onboard diesel. Less engine hours mean less maintenance and downtime, which has a positive impact on total cost of ownership, as well as the higher value retention, the company claims.
More than modifications
The consistent development of electric drive concepts is more than a mere modification. This is proven by the numerous innovations introduced by Keestrack during its transition.
Among others, these include specific plant components, such as the company’s own series of compact wind sifters or the new optionally electric driven neodymium overbelt magnets. Despite a higher separation capacity, their weight is considerably lower, up to 400 kg less than conventional ferrite magnets and this significantly reduces the transport weight of the diesel-electric machines.
The most advanced result of Keestrack’s research and development into its e-technology is the new track-mounted stacker S5e Solar.
The stacker is the first directly solar-powered mobile processing plant worldwide. Photovoltaic panels span like a sun sail over the 23-meter-long conveyor belt. Generating 9 kWh, the panels feed the system’s battery with a capacity of 23 kWh, installed on the chassis. The 22 kW conveyor belt and the tracks (2 x 15 kW) are directly electric-driven, and an electric pump unit (2 x 15 kW) supplies the hydraulic lifting cylinders. If bad weather causes an insufficient solar power supply or intensive continuous operation exceeds the solar recharging capacities, the system can be powered or recharged via available external sources, such as upstream diesel-electric crushers and screens, or via mains plug-in.
Another innovation is the drop-off power-supply module Keestrack is offering on new large plug-in plants.
On-board diesel and generator are combined in a detachable unit, which can be positioned remotely from the machine, far from dust and vibrations during diesel-electric operation and easily accessed for control and maintenance.
Since the main control with energy management and all electric drives are installed on the chassis, the drop-off modules can be completely dismantled and stored during plug-in operations via mains.
An e majority
Keestrack already offers 80 per cent of its 22 models across six series as diesel-electric hybrid variants, and 75 per cent of its equipment is also available as full electric plug-in systems.
During recent years, Keestrack consistently followed the trend in the development of its product range. Across all crushing technologies and machine sizes existing mobile crusher models have been presented in new electrified generations. Completely new models or series have even been developed on a specific diesel-electric plug-in design base.
Some of these models are only available as e-version, as the practical advantages and the high gains in cost efficiency of their diesel-electric/plug-in drives are so successful, so there is no reason to provide these in conventional diesel-hydraulic drives.