Energy efficiency in the drive technology
July 16th, 2010 - The starting points for the reaching of an optimal energy saving solution within the range of the food and food industry are determined by the customised application. The focus is on the total system with the goal in consideration of the consisting process cycles and the use of the suitable drive technology
- to reduce the power losses
- to optimise the power demand and
- to use the available generating energy in a reasonable manner.
Reduction of the power losses
The optimisation of the component efficiencies plays a central role with the efficiency increase of automation systems.
The political activities lead likewise in this direction establishing world-wide efficiency regulations being mandatory for the use of energy savings motors. In the European Union for example the use of energy efficient motors is stepwise specified in the context of the implementation regulation of the EuP guideline 2005/32/EG (IE2: High Efficiency, IE3: Premium Efficiency). However, applications only sporadically demanding their performance are not suitable for the use of energy savings motors whereas the saving potential is particularly high with continuous operation as e.g. with conveyor belts or ventilation systems.
In addition, with the motor’s selection its characteristic should be considered. Modern synchronous motors for example create in fact the double initial moment compared with asynchronous motors. Particularly a bottle transport in the beverage industry needs an increased break-away torque when starting due to blockings. In such application the higher overload capacity of the synchronous motors permits a smaller dimensioning of the drive according to requirement and leads therefore to noticeable saving effects in continuous operation.
A further important starting point is the use of efficiency-optimised gearboxes such as bevel gear or helical gear.
Optimisation of the power demand
Beside the use of counterweights (e.g. with hoists) the load torque can be reduced by the use of efficiency-optimised transfer elements optimising the power demand. So for example the use of V-belts should be avoided due to the lower efficiency (about 92-94%) compared with the flat belt or toothed belt (efficiency about 96-98%).
In addition, by the use of a frequency converter the power demand can be optimised too. Apart from functionalities, such as the energy savings modes (automatic cutting off) the process can be adapted to the actual requirement by the stepless closed-loop control of speed and torque and thus energy efficient be arranged.
Use of the released energy
A further approach is the use of the released energy in the system, for example if a load with an elevator or with a stacker crane drives downwards and thus the motor is used in a generating manner. A smart solution immediately provides the energy that a drive produces in the generating operation for another drive as motoring energy via a DC link coupling.
A further opportunity to use generating energy of a drive for other loads and thus to reduce the total energy consumption is to apply for a regenerative feedback into the supply.
Email Roman Mackert.
You find more information on the energy saving site of SEW.