Ilsemann Automation is one of the world's leading suppliers of handling systems for injection molding technology. The company uses an XYZ gantry with multi-axis coordinated servo drives to remove the finished plastic cups from an injection molding machine. The Bremen-based company has secured a competitive edge thanks to the newly designed energy supply system developed together with SEW-Eurodrive. It offers three key advantages: Operational reliability, energy efficiency and the limitation of peak loads.

The development objective resulted in an indirect supply of the multi-axis system from an EMF plate capacitor. This supplies the DC network of all drives through its storage buffer with the required reliability and safely compensates for possible mains fluctuations up to total failure. The capacity of the unit is dimensioned so that the handling unit can safely complete the work cycle once it has started before the gantry shuts down in a controlled manner. This eliminates the risk of collisions in the open injection mold.

The gantry drives and other axes in the DC link are supplied by a central power supply from the MDP92A series. The "Power and Energy Solutions" modules are arranged on the left. © SEW-Eurodrive

Accumulator has a balancing effect
The buffer accumulator in the Ilsemann handling units absorbs the energy released from the motors during braking and makes it available to the drives again when they accelerate. The capacitor module thus acts like a short-term battery with a booster function when accelerating. Ideally, this setup works so effectively that no kinetic energy has to be dissipated via braking resistors. Measurements have shown that the intermediate buffering halved the energy consumption of the gantry. In comparison, regenerative units would be much less suitable for this application because they are nowhere near as efficient.

Load management reduces costs
The retention of braking energy in short-term storage also has a positive effect on grid usage fees and the annual demand charge. Companies must pay this to the energy supply company for the power they receive. It should be noted here that extraordinary load peaks result in enormous costs after just a few minutes because the electricity procurement costs are billed annually. A 15-minute period is used for measurement.

The motors in the XYZ gantry - here the servomotor for one axis of the removal system - are powered by drive controllers from the Movidrive series. © SEW-Eurodrive

Here is an example calculation for a company with its own medium-voltage supply: More than 2,500 hours of annual power consumption and costs of 120 euros per kilowatt. If load peaks drive up the planned power consumption by 100 kilowatts within the 15-minute period, this results in costs of EUR 12,000. Effectively smoothing load peaks is of paramount importance in the context of energy management. This effect is accompanied by a leaner supply installation, because the power peaks of the Ilsemann portal are served from the storage system. As a result, the supply infrastructure only has to supply continuously.

The sum of advantages of SEW-Eurodrive's "Power and Energy Solutions" quickly pays off and is also worthy of an award in the literal sense. In 2019, the state of Baden-Württemberg awarded the Bruchsal-based company's intelligent power and energy management system for industrial drives the Environmental Technology Prize in the energy efficiency category. as