MATERIALS HANDLING
Tis loss of production was naturally unsustainable in the long term. A visit to LKAB in Kiruna gave very positive feedback on Hägglunds’ direct hydraulic drives.
Te choice fell on two Hägglunds CBp motors with an installed power output of 2 x 630kW and a maximum capacity of 3,000 tons per hour. Te reason for choosing these motors was a requirement for compact design and maximum efficiency. Tey have not regretted the decision. Te biggest benefit of all, according to Sundqvist, is the built-in redundancy and high operational reliability. Te belt is driven by the Hägglunds CBp motors and drive units, and a standby pump now makes it possible to maintain operation even if one of the units stops. “We have not had a single incident, everything has just worked the way it should,” he says. “Tere was no need for any construction changes to install the new drive, so we completed everything during the May shutdown.”
A TROUBLE-FREE SYSTEM Automatic load sharing is another benefit, which leads to reduced vibration and wear in the drive chain compared to before, when there was a much higher load and demand on the single gearbox.
all, according to Håkan, is the creep drive. “It’s very useful when we need to inspect the belt for damage from reinforcing bar and other scrap that sometimes gets caught up from rock reinforcement. Now we can gradually advance the belt to the point of damage and check it,” he says. Te emergency stop function is also
LKAB opted for Hägglunds CBp motors “Te drive system works so well that
you almost forget it is there. It just keeps on running. Te only thing we have had to do is replace filters,” says field mechanic Håkan Hansson. Te hydraulic drive is specially designed for dusty environments, and all the hydraulic components are isolated from the electric motor. Te system is now easy to service, lightweight and easy to keep clean, according to Håkan. “With the old 6.000V motors and
gearboxes it was not possible to wash off the ore dust with water, so we had to vacuum-clean them regularly,” he says. Te soft start of the hydraulic drive is gentler on the mechanical components when you start up. But the best feature of
appreciated, as it enables the Hägglunds’ CBp motors to stop the belt in less than one metre from full speed. “Te process was analysed in detail and we carried out a thorough risk analysis. Naturally we want to be able to stop the belt as quickly as possible to prevent any injury to employees,” says Sundqvist. In July 2018 the conveyor belt had an
availability figure of 99.5% and ran for 23–24 hours per day. “Te few stoppages we had were just
caused by iron scrap along the belt. Now it is important that we carry out routine maintenance so that there are no problems in the future either. Te big problems always arise after a breakdown, so we need to eliminate them completely,” concludes Pär.
Uno Sundelin is with Hägglunds.
www.boschrexroth.com
LKAB engineers have
positive feedback about the new drive system
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