Drives and Controls Magazine

Free tool calculates motor system efficiencies

16 November, 2011

The Electric Motor Systems Annex (Emsa) group, set up under the auspices of the International Energy Agency (IEA) to promote high-efficiency motors, has developed a free, impartial software tool that helps users to design efficient motor installations.

The Motor Systems Tool is intended to help engineers, machine-builders, machine component suppliers, energy consultants and others to cut electricity consumption.

The tool takes into account all four main parts of a motor system – the primary load, the transmission, the motor and its controls. The system efficiency is determined by calculating the load and efficiency for each component. The tool contains standardised models for pumps, fans, compressors, belt drives, gearboxes, motors, variable speed drives – and combinations of these elements.

The user enters a known duty point (in rpm or kW) and the tool uses this to calculate individual efficiencies. It can also show how efficiencies change if components, duty points or motor connections are altered. All calculations are dynamic, with results being shown instantly.

Emsa says that an ideal design will meet the requirements of the application, while not over-sizing the components – a common practice that results in excess energy use.

The Windows-based tool also includes algorithms for energy consumption and for speed variations. A drive variant analysis can show energy consumption at an unchanged duty point with an alternative drive connected.

The Motor Systems Tool can be downloaded free of charge from Emsa’s Web site.