Copper rotors: Helping you move from IE2 to IE3

02/09/2015 02
By Nuno Fernando

From 1 January 2017, energy efficiency class IE3 will apply to motors from 0.75 kW to 375 kW. This extends the situation in force since the start of 2015 when IE3 motors became mandatory for motors with a rated output between 7.5 kW and 375 kW. Hugh Falkner, Principal Consultant at Atkins Energy PLC, explains how copper rotors can ease the transition from IE2 to IE3.

 

What challenges might OEMs face when implementing the latest IE3 regulations?

They are likely to be wondering how to fit a new, more efficient, larger motor into their products! The extended, lower range of IE3 implementation applies to a host of smaller products including some of those found in many mass market products such as pumps and fans. Increasing the length of the motor to achieve the higher efficiency could involve redesign of their products.

Is there an alternative?

OEMs don’t have to keep to the standard offering of aluminium motors from motor manufacturers. Moving from an aluminium rotor to a copper rotor is a very interesting alternative.

What’s the main benefit of a copper rotor?

Basically, it allows OEMs to gain more efficiency from a given motor size. This is because for the same efficiency, the copper rotor motor will be smaller than the equivalent aluminium rotor motor. So there’s no need to redesign parts or change manufacturing processes.

Does a copper rotor give other benefits?

Yes. Higher corrosion resistance, higher conductivity, cooler running, increased reliability. All these things can help make longer lasting products, and more satisfied customers.

But isn’t copper more expensive than aluminium?

The economics of copper rotor motor technology are currently very interesting, because the price of copper has been steadily falling throughout 2015, making a copper rotor more cost-effective. In addition, because a copper rotor is shorter than the equivalent aluminium rotor, it requires less costly punched steel lamination, and so now is a good time to review previous economic calculations.

What about future regulations? IE3 to IE4, for example?

This is certainly within the scope of the European Commission’s Ecodesign impact assessment study that is currently being conducted, although no country has so far made the leap to set IE4 as the mandatory minimum energy performance level. But what is looking very likely is to follow the USA’s lead and further extend the scope of high efficiency motors to smaller and larger sizes. Whatever the efficiency challenge, a copper rotor still offers significant space savings and a competitive price compared to the equivalent aluminium rotor motor.

Is the IE3 regulation applicable throughout the world?

IE3 is certainly the rallying point for regulations around the world (see map). It’s a global drive for harmonization of high efficiency motors that will make it much easier for manufacturers, specifiers and users. Of course, some motor manufacturers are already offering IE4 copper rotor motors. Maybe OEMs could already start to consider fitting IE4 copper rotor motors into their products. These give even better savings, especially for applications running at high loads for long periods, and contribute to a premium brand image.