As the engineering sector looks for sustainable, economic ways to achieve greater automation, what’s holding back wider adoption of the IE5 motor?
Motors convert electrical energy into mechanical energy to drive parts. Today, they are ubiquitous, with estimates of over eight billion electric motors in use in the EU alone. They come in all sizes for use in homes, offices, factories, hospital equipment and factory equipment.
They are estimated to account for over 50 per cent of global electricity consumption, and with rising fuel prices, energy-efficient operation has become an economic as well as an environmental issue. Making more energy-efficient motors available will contribute to reduced CO2 emissions and help countries achieve net-zero targets.
Industrial motors are used to control torque and speed on conveyor belts, robotic arms, automated guided vehicles and in compressors to regulate the volume of air, gas or liquid running through pipes.
They are graded in terms of International Efficiency (IE) classes, with each efficiency level generating 10 to 20 per cent less energy loss in the motor operation (see boxout below).
The IE5 class is defined for motors for variable speed operation. Richard Gee, UK sales manager, motors and generators at ABB, says IE5 motors produce up to 50 per cent lower energy losses than equivalent IE2 motors and 20 per cent lower losses compared to IE4 motors.
Synchronous motors can use permanent magnets or can create torque through magnetic reluctance. Today, there are IE5 permanent magnet (PM) motors, IE5 synchronous reluctance motors and IE5 PM-assisted synchronous reluctance motors available. There is work being done on creating an IE5 induction (or asynchronous) motor, but it is difficult to get one to such a high efficiency, says Norbert Hanigovszki, director of drives intelligence at Danfoss.
The type of magnet used affects a motor’s cost and size. Rare earth materials used in permanent magnets are scarce and geo-politically sensitive because most are mined in China, explains Hanigovszki. Ferrite is a cheaper magnet but it is weaker, resulting in a larger motor.
Estimates put IE5 motors at no more than 1 per cent of the total motor market today. Part of the slow take-up may be due to the fact that governments do not require any motors above IE3. This may be dictated by the geography of motor manufacturers, observes Hanigovszki, with Danfoss, ABB and Siemens in Europe and GE and Allen-Bradley in the US but no manufacturers in China.
As a result, IE5 motors are a tool for differentiating products but viewed as a luxury upgrade rather than a necessity. Given that an IE5 motor has to be manufactured specifically, and at a premium, and bearing in mind that savings may not be realised immediately, the total cost of the project should be considered, not just the initial cost of the motor, advises Hanigovszki.
This is particularly true for municipal projects where IE5 motors can save running costs and energy use for large projects which run motors at partial load or partial speed, such as heating, ventilation and air conditioning (HVAC), pumping fresh water and wastewater treatment. The electricity used to supply water to towns and cities is usually the highest electricity charge, says Hanigovszki, so any savings will be significant.
