A production facility that turns barley into malt for use in beer and whisky production has increased productivity and safety by installing a new germination machine controlled by an ABB variable speed drive (VSD).

The ABB industrial drive, ACS880, controls four gear motors located on the corners of a fifteen-tonne trolley that is used to agitate the barley during the germination process at Bairds Malt’s production facility in Witham, Essex. Should a blockage occur, the VSD slows the speed of the motors driving the trolley – known as a turner – giving it time to work through the obstruction. Since the new system was installed stoppages at the site have been reduced from once a fortnight, on average, to practically zero.

In the previous installation, the turner was powered by a single motor operating at a fixed speed. As a result it was unable to slow down to negotiate any blockages, such as hard lumps of barley. The machine would attempt to break up any obstruction by trying to drive through it. This would cause a spike in current, making the machine break down.

The blockages also had more serious implications, as the machine’s attempts to drive through the restrictions would, on occasion, cause the 15 tonne turner to ‘jump’ backwards, putting workers at risk of serious injury.

Bairds designed the new machine itself and approached ABB authorised value provider, Gibbons Engineering Group, to design and supply the control package.

With the new system, the VSD takes its signal from a programmable logic controller (PLC). The PLC monitors the load drawn by the gear motors to detect spikes in current of 20 percent or more that signal a blockage. Should this occur, the drive reduces the speed of the motors to 50 percent, giving the turner time to work through the obstruction. It repeats this process three times. If, after this time, the blockage is not cleared, an alarm is triggered to notify the operator.

Since the new machine was installed, stoppages at the Witham site have been reduced to almost zero. In addition to increasing production time, this has improved safety for staff as there are no longer any blockages that could force the turner to move out of place.

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