Electricity + Control May 2019

DRIVES, MOTORS + SWITCHGEAR

The advantages of motor independence in drive selection

Anna Hildebrand Jensen, Danfoss

Motor efficiency is a key concern across industry. Plant operators and original equip- ment manufacturers (OEMs) routinely specify electric motor installations according to European or other regional efficiency ratings.

Take Note!

1. To achieve optimal econ- omy in motors and drives it is important to take account of more than IE and IES energy-efficiency ratings. 2. Universally compatible drives offer full adapt- ability to new motor tech- nology as well as other advantages. 1 2

I n Europe, the IE classification gives an indica- tion of the energy efficiency of the motor and the motor controller (also known as ac drive, variable speed drive, or frequency converter) respectively, and the IES rating defines the effi- ciency of the entire system of motor and motor controller combined. The practice of specifying IE and IES is so convenient and effective for buyers and suppliers – and not least, for legislators – that it is well on the way to going global in various forms. More than just IE However, for optimal economy it is important to be aware that the energy- and cost-efficiency of sys- tems require focus on more than just IE and IES classes. High motor and motor-drive system efficien- cy is always a strong argument, but there are oth- er important considerations which include logistics, availability and, importantly, return on investment. All these factors influence total cost of operation:

are related to their nominal point. Efficiency class- es do not take account of part load efficiencies.

Flexible logistics Flexibility means the ability to accommodate changing customer specifications and new tech- nological trends, over the lifetime of the applica- tion. The best ac drives are compatible with all state-of-the-art motor technologies. Research ex- perts monitor upcoming trends and include new motor algorithms in software updates of the drive whenever the potential is good. Quick changeover When the supplier cannot supply a replacement motor as planned and there are bottlenecks in de- livery, a change to an alternative supplier or alter- native motor technology is often the best solution. That is when the ability of the drive to adapt to a different motor technology can be priceless. The best of these universally compatible drives offer full adaptability to a new motor technology even without the need for special firmware. Freedom from supplier dependency Limiting supplier dependency offers other advan- tages too, beyond overcoming delivery delays. In the lifetime of an application, no maintenance

- Flexible logistics - Quick changeover

- Freedom from supplier dependency - Adaptability in difficult locations.

Furthermore, it is important to realise that the effi- ciency classes of the motors and motor controllers

4 Electricity + Control

MAY 2019