The IE4 effect on the motor market

11 March 2014

The IE2 regulations effectively cleaned-up the lower efficiency end of the market – if an application requires a motor to operate rarely, then its energy consumption is not so critical and users will want the cheapest machine they can buy that will be reliable. The IE2 regulations are intended to make sure that new motors being supplied into these conditions still meet a minimum standard of efficiency.

IE4 is a further development that many manufacturers are now talking about but that fewer are actually delivering. There is a cost premium to these motors, but the market uptake is not being driven by legislation, rather by shear economics.

For a small to medium sized electric motor that is running close to capacity for the majority of the time, used in a continuous manufacturing process for example, the additional investment in terms of purchase cost will be quickly outweighed by the energy saving.

Motors that meet IE4 energy efficiency standards are usually permanent magnet arrangements, where the permanent magnets maintain their own persistent magnetic fields and are generally made from rare earth metals, which are more expensive to manufacture but are significantly more powerful than standard magnets.

When used in a motor application, the motors usually require an inverter drive to power the motor, but the efficiency can be very high, of the order of 96%.

An end user in Germany carried out a direct product comparison test to see how Bauer’s IE4, super premium efficiency permanent magnetic synchronous motors (PMSM) performed against a standard asynchronous motor. The test was carried out on a Hüber disc thickener at a wastewater treatment plant in Germany in partnership with inverter drive specialist Danfoss. Once installed, the motor was found to operate with 87.7% efficiency and delivered energy savings of almost 40%.

Markus Kutny, product specialist for Bauer Gear Motor PMSM, said: “Energy efficiency has to be one of the key determining factors when specifying geared motor solutions today. It is becoming more important that a drive’s lifelong running costs are considered; rather than simply the cost of procurement. We have developed the new motor range in anticipation of the new IE4 classification and to offer our customers the very best in terms of efficiency.”

Bauer Gear Motor’s range of PMSM's already fulfil the requirements of the soon-to-be-implemented IE4 (Super Premium Efficiency) classification – evidenced by their potential to achieve energy savings of up to 40% compared to an IE2 inverter-driven squirrel cage motor.

The PMSM series are environmentally-friendly motors, employing an efficient design of rotor that integrates embedded permanent magnets made from the rare-earth material, instead of the squirrel-cage rotor found in induction motors. This design is said to offer a number of key benefits. It reduces heat losses from the rotor by 100%, total losses by approximately 25%, and increases total efficiency by 10% or more. For the PMSM user, this improved performance translates into lower total cost of ownership, a reduction in CO2 emissions, and ongoing savings that buffer against future increases in energy costs.

Importantly PMSM drives can produce higher torques for the same installation volume as conventional induction motors, a factor that allows cost saving, through the ability to specify a smaller motor size in some applications.

The synchronous design of the PMSM motors is also said to mean that they can maintain constant speed, independent of the load. This means that motor speed does not vary, despite overload variations, or in cases of voltage drop, as long as the mains frequency is kept constant.

The PMSM motor series is available in ventilated and non-ventilated configurations across the power range from 0.55kW to 15kW. They operate on 380V to 500V power supplies, and are rated for inverter duty, offering an extended speed range with constant torque.

The low operating and maintenance costs of the PMSM motors mean that they provide the optimum energy saving drive for use on fans, pumps and compressors; and for constant torque applications such as elevators and conveyors.

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