A permanent reduction in CO₂ emissions

Since much of industry’s CO2 comes from electricity consumption, industry itself would also be quite happy to reduce its CO2 emissions, if it also means reducing the size of its electricity bills.

The internal combustion engine has long been the villain of the piece where CO₂ emissions are concerned. More recently, electricity generation – and, by implication, electricity over-consumption – has been cast as another of the bad boys. Now, particularly in the field of industry, it is electric motors which are taking on the role and taking the blame. Is there anything to be done to reclaim their reputation?

The world needs industry, however much the greenest of the greens might wish it didn’t. But the world doesn’t need industry to be an unnecessary polluter or generator of CO₂. And since much of industry’s CO₂ comes from electricity consumption, industry itself would also be quite happy to reduce its CO₂ emissions, if it also means reducing the size of its electricity bills. In fact, the figures speak for themselves: industry is one of the world’s major consumers of electricity, and motor systems are responsible for as much as 65% of industry’s electricity consumption. At the same time, the bill for electricity represents more than 97% of a motor’s total operating costs. So, cut the power consumed by an electric motor and you not only cut energy bills for industry, but also significantly reduce global CO₂ emissions. It’s a win-win situation.

The drive for lower emissions and lower bills has led design engineers and motor manufacturers to investigate beyond the traditional motor solutions, to develop new, high-efficiency motor technology. Now the forthcoming European energy-efficiency legislation has added extra impetus, as soon it will simply be illegal to sell motors which fail to meet the standards’ lower energy-consumption parameters.

One of the areas of development which proved promising at an early stage was Permanent Magnet (PM) motors. Subsequently, extensive investment in R&D by automotive manufacturers has led to major leaps forward in this technology.

These motors consist of a stator and a permanent magnet rotor part. as there is no rotor current in a PM motor, and only the stator endings carry current, I₂R losses at the rotor are eliminated and overall copper losses are around half that of induction motors. (This has the additional effect of reducing the operating temperature of the bearings, which in turn leads to longer lubrication intervals, lower maintenance and an increased service life.) PM motors are also smaller and lighter, and create higher torque than traditional induction motors. Although the technology has existed for more than twenty years, it has mainly been used for low speed, high torque servo motors. So why hasn’t PM technology been more widely taken up for general purpose applications?

The reason for lack of uptake is that PM motors have generally required a larger capital outlay, and also require a speed sensor for control, which again adds cost and introduces an unwanted element of unreliability. If cutting your carbon emissions and electricity bills demands spending more money, yet at the same time reduces reliability, then it’s obviously much easier to carry on as normal and wait for something better to come along. Fortunately, something has. That something is the speed sensorless – or open-loop vector control method – motor, made possible by the recent development of low-cost, high-performance CPUs.

Open loop vector control methods are usually one of two types: voltage control based on motor parameters, with the permanent magnets located inside the rotor, or a field-oriented current control method based on instantaneous estimation of motor speed and magnetic pole position. Implementing the voltage control method is much easier than the field-oriented control method, and the IPM motor, as it is known, is more robust at high speed. Employing a high-frequency signal injection method for motor control, the IPM motor also generates 200% torque at standstill without a speed sensor. These advantages have made IPM motor technology the preferred choice of manufacturers of the new PM motors, such as Yaskawa.

Yaskawa is the world’s largest manufacturer of ac inverter drives, servo and motion control, and robotics automation systems. It has also been leading the field in innovation in electric motors since the early years of the twentieth century, so it was only to be expected that it would be one of the first to develop practical, affordable, effective PM motors for general applications.

The Yaskawa ECOiPM motor conforms to the new IE3 efficiency class, and was developed specifically for applications where eco-design is the most important factor. In fact, wherever a high-efficiency motor with speed control is required to maintain efficiency levels – such as fans, pumps and compressors – the ECOiPM motor is a cost-effective solution.

With power ratings ranging from 0.4-7.5kW, and voltage classes from 200-400V, the ECOiPM comes in a compact frame size and is available in foot and flange mount models.

Together with the Yaskawa V1000 inverter drive, it offers a combination with guaranteed performance, which requires only a change of parameters within standard inverter software, and relies on Open Loop Vector Control. As can be seen from the life cycle cost analysis chart below, the ECOiPM motor and inverter combination delivers a dramatic reduction in energy costs and – despite the higher initial purchasing costs – a lower overall Life Cycle Cost.

Yaskawa electric has recently partnered with ERIKS, so a whole range of electric motors – including the carbon emission reducing ECOiPM – is now available supported by ERIKS’ know-how, to help you find the right motor solution for your application, your CO₂ reduction targets, and your bottom line.