TECHNOLOGY | SIZE REDUCTION
Right: The HiTorc direct drive from Vecoplan
suitable for increased throughput and deliver enough torque to handle foreign material. Synchronous motors were considered for their power and acceleration, as well as their ability to start up quickly after braking, which seemed ideal for shredding. A further advantage of these drives is that they produce the necessary torque by means of a magnetic field that acts directly on the shredder shaft. Unlike conventional electric motors, they do not require a gearbox and instead rely on a frequency converter. Gears also mean friction. Extraneous material causes shocks in the shredding process that must be absorbed by the flanks of the gear teeth or the drive belts. These components wear out and have short maintenance intervals. The service personnel have to replace them on a regular basis. The HiTorc solution is a slow-running electric
direct drive for shredders. The drive has no mechan- ical components like belts, gear wheels, flywheels or clutches. This makes the shredder much more robust. In the absence of these mechanical compo- nents, the flywheel effect from the solid steel rotor and the motor torque can be combined for high efficiency. The company adds that conventional drive systems usually are not able to start up again if a full shredder has to brake. A worker first has to clean out the machine by hand. In contrast, with its power, the HiTorc improves the start-up and reversing behaviour because the mass moment of inertia in the drive system as a whole is significantly reduced. The high availability of the torque enables problem-free start-up under load, for example, when the shredding area is full. The operator can restart the machine at any time simply by pushing a button. There is no need to empty the hopper. Due to continuous speed analysis and electrical
Right: Vecoplan says its shredders efficiently process packaging made from plastic, metal and composite materials. Household waste is
another input material. The rotor drive is a key element
40 PLASTICS RECYCLING WORLD | May/June 2021
current evaluation, the fully automated control system can detect machine overloads at an early stage of the ongoing shredding process. If an obstruction is encountered, the rotor shaft stops in just a few milliseconds. This prevents damage to important parts. After a short counter-rotation, the Vecoplan drive turns in the required direction again in a few seconds. According to Vecoplan, the HiTorc drive is
considerably more efficient than systems with gears. The absence of mechanical drive elements accounts for an efficiency gain of about 10-15%. This factor makes the synchronous motor espe- cially efficient under partial loads. During idling it draws only about a tenth of the power required by a comparable asynchronous motor. Situations like this are especially common with inhomogeneous materials and irregular input. Energy savings of up to 40% are possible as compared with other electromechanical drives. For hydraulic drives, the figure can be as high as 60%. Vecoplan offers HiTorc drives in various perfor- mance classes, depending on the application. The company adds that it finds the right combination of frequency converter and direct drive motor based on the output, torque and rotor speed required in the given case. The VEZ 3200 TT, for example, is powered by two synchronous drives, each with a peak torque of 110,000 newton metres. In opti- mised master/slave operation, the drives are regulated via two frequency converters in extended vector control mode. The controller integrated in the frequency converter ensures that the optimum torque is available at the rotor shaft at all times and in all operating conditions.
CLICK ON THE LINKS FOR MORE INFORMATION: �
www.untha.com �
www.lindner.com �
www.weima.com �
www.dcw.co.uk �
www.fercell.com �
www.neue-herbold.com �
www.zerma.com �
www.vecoplan.com
www.plasticsrecyclingworld.com
IMAGE: VECOPLAN
IMAGE: VECOPLAN
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