Brammer commitment to service

Bammer, the industrial maintenance, repair and overhaul product specialists, are a long-standing supply partner to CEMEX Aggregates’ Goddard Quarry, near Sheffield, so when an unusual problem affected one of the quarry’s crushers, Brammer’s technical expertise was called upon to help find a solution.

CEMEX engineers had identified that the aggregate being produced did not always match their customers’ exacting requirements, as existing impact crusher speeds were creating too much waste material in the form of –5mm dust.

To keep waste generation to a minimum, optimum crusher hammer speeds were identified as 1,030 rev/min for new hammer heads and 200 rev/min for worn hammer heads. However, achieving these speeds precisely and consistently using traditional V-belt drives, as well as having to change the V-drives to set a new speed, was proving both difficult and time-consuming.

Following site visits by a technical specialist from Brammer’s inverter drive technology team and discussions with CEMEX engineers, Brammer recommended an inverter drive as the best-possible solution to the problem. This would provide infinite variation in motor speed and allow the optimum crushing speed for both new and part-worn hammer heads to be quickly and easily identified and programmed. Moreover, this method would not require the changing of any of the mechanical drives, thereby saving significant production and engineering time.

The inverter drive selected comprised a 200kW, 361A, FLC 400V, three-phase AC unit incorporating: true open-loop vector control with high torque and fast dynamic response; self-tuning for automatic drive set-up to match the drive to motor and load in vector modes; and an optimal braking function to eliminate the need for braking resistors. The
unit was supplied ex-stock from Brammer’s national distribution centre and is covered by a three-year warranty agreement.

In addition, an IP54-rated inverter panel was designed to house both the inverter and line choke. This was fully wired and tested, as far as possible, prior to dispatch.

CEMEX are now able to run new hammer heads at precisely 1,030 rev/min, which results in approximately 20% less waste and, therefore, 20% more saleable product. And with waste product reduced, it is no longer necessary for the tertiary crusher speed to be reduced, resulting in increased production rates. In addition, as the crusher now runs at the optimum slower speed, the life of the hammer heads has been increased by approximately two weeks.

Despite a five-figure investment, CEMEX engineers have calculated that a payback period of less than two months has been achieved through the increase in saleable products and the longer life of the crusher hammer heads.

For further information on Brammer’s extensive MRO product range visit: www.brammer.biz