Keestrack showed its full-electric tracked processing line at Fredheim Demo Days in Spydeberg, Norway. Machines on-site included the B4e jaw crusher with stacker S5e; the H4e cone with three-deck-after-screen module; and two-deck-classifier K3e for five end-product fractions.
With a feed size of 600 mm (23.6 in.) and different sets of end products, the combination reached a maximum production of 180 tph. Without activating their onboard-diesels all machines were powered through a single 500-kVA external gen set. Consumption analyses over several days gave average values of under 60 liters (15.85 gal.) per hour.
“We were surprised by these results,” said Keestrack President Kees Hoogendoorn. “Even if these values are quite specific, they clearly reflect the high economic potential of our full-hybrid technology. Applied in a mobile multi-stage processing line, as presented here for the first time, it offers great advantages for the producer. Not only in daily practice, but specifically in long-term evaluation if we consider lower maintenance costs and longer service life.”
Keestrack said that the “full-hybrids” line up with the early introduction of modern load-sensing systems in diesel hydraulic drives and the partial electrification of crushing and screening plants through the use of electric motors on conveyors and separator components.
“Every new level in development brought important savings in diesel consumption,” said Hoogendoorn, referring to the 20 to 30 percent improvement steps, made through modern hydraulics, diesel-electric components and the external “plug-in” operation, which is available throughout all Keestrack plant technologies. “With their substantially smaller hydraulic circuits our hybrid systems provide advantages in maintenance, availability and safety – especially when working in environmentally sensitive areas,” Hoogendoorn said.
While the screeners and conveyors on hybrid Keestrack classifiers and stackers are operated electrically – the diesel-driven hydraulics only supplies hydraulic cylinders and crawlers – all Keestrack crushing units were up to now only powered directly through the on-board diesel engine. “Electric drives supplied via external gen sets or mains certainly offer high saving potentials, but without compromising the plants’ mobility, crushing performance and productivity, which depends today also on optional modules with high power demands,” Hoogendoorn said.
As a first result of these changing technologies, Keestrack presented at the last Bauma show the tracked mobile cone crusher H4 with 345 kW/330 KVA diesel/generator module, 132-kW electric drive for the crusher and extensively electrified conveyors and screening components. Despite its comprehensive equipment, including an optional three-deck after-screen with oversize conveyor, the compact, transport friendly plant, weighs only 46 tonnes (50 tons) and can be operated “plug-in.”