Solutions for shredders 

Shredders are an integral and important part of the recycling process. This is because they reliably break down materials, thereby facilitating recycling and transport. They reduce volume, separate material streams and prepare recyclable materials for sorting, granulation or thermal processing. In doing so, they increase the efficiency of industrial processes, ensure stable material cycles and make an important contribution to resource conservation and sustainability. 

Originally, shredders were often operated directly on the mains supply. As a result, the motor ran at a constant speed without flexible adjustment of torque or speed. Under overload, the shredder would often jam or trip the circuit breaker. Restarting was slow and time-consuming for mechanics. To overcome this lack of flexibility, some OEMs employed hydraulic systems. The hydraulics enabled variable speeds and high torque at low speeds, but resulted in lower energy efficiency, higher maintenance costs (oil leaks, pump wear) and less precise control. 
 

Nowadays, it is common practice to operate shredders using appropriate inverter technology. There are many reasons for this: 

• Lower energy costs: Drives regulate speed and torque according to the material load, thereby avoiding energy wastage. 

• Higher throughput: Automatic torque boost and reverse functions keep the shredder running even with heavy or jammed material. 

• Reduced wear and maintenance: Smoother motor control means less mechanical stress on gearboxes, bearings and blades. 

• Process flexibility: Drives enable rapid adjustment of the rotor speed to suit different input materials, from light plastics to heavy wood or metal. 

• Improved uptime: Integrated diagnostic and protection functions prevent damage and unplanned downtime. 

Conclusion: KEB drive controllers regulate electric motors and combine the efficiency of electrical systems with the flexibility of hydraulics. COMBIVERT drives enable torque amplification, reverse operation and adaptive speed control – all whilst reducing energy consumption and maintenance requirements. 

A well-designed, comprehensive solution for shredders starts at the IIoT level. For example, the open automation platform NOA offers, among other things, the option of predictive maintenance. This allows problems to be resolved before they even arise. System downtime is reduced, throughput is increased and costs are lowered. Furthermore, the NOA Portal provides fleet management that offers an overview of KPIs or the machine’s status anytime, anywhere. 

For its shredder system solutions, KEB relies on motor and drive technologies that can enhance the application’s energy efficiency. The use of torque motors or synchronous reluctance motors can contribute to this. The reason: torque motors can transmit very high torque directly to the shredder shaft without a gear unit, thereby avoiding mechanical losses. They are ideally suited to the frequent start/stop cycles, direction changes and overload conditions typical of shredders. 

Synchronous reluctance motors also offer an option that features lower rotor losses compared to induction motors, resulting in reduced heat loss and higher efficiency. Thanks to their standardised design, they can be easily integrated into existing shredder systems using a gearbox. In the past, KEB has, among other things, carried out series deliveries of synchronous reluctance motors in a water-cooled version with a customised tapered shaft for the shredder industry. The shredder’s main drive can be implemented using one or two motors. The motors operate in leader/follower mode on the same shaft of the shredder and can be synchronised via internal CAN communication. 

Reliable speed control is essential for optimal management of the shredder’s process behaviour. To this end, KEB offers multifunctional drive systems in the form of the COMBIVERT F6 Drive Controllers. The drives are available with various mounting and cooling options and feature safety functions already integrated into the unit. The drives also provide stable control at high speeds. 

Even a well-sealed industrial control cabinet does not offer 100% protection against external influences. Furthermore, the heat generated within the control cabinet itself can pose a challenge for the drive components that should not be underestimated. For this reason, KEB drives are designed for a range of ambient temperatures. Stress tests are carried out as early as the development phase to verify, prior to the actual deployment of the drives, whether the components can reliably withstand extreme conditions.