The energy-saving benefits of using Leroy-Somer drive and motor solutions have been highlighted in a test report on electric motors by Energimyndigheten (Swedish Energy Agency). 

The agency commissioned the test to investigate claims made by manufacturers of electric motors in various efficiency classes, when used in conjunction with a series of different variable speed drives. 

The investigation showed savings of around 5,700 kW hours per year can be achieved from a single Leroy-Somer Dyneo® LSRPM 15kW electric motor from Leroy-Somer, equivalent to the entire annual household electricity consumption for a four person household. 

The independent tests, the first of their kind in Sweden, follow amended EU legislation which concerns the efficiency of electric motors in industry. Since January 2015, all new electric motors of powers from 7.5kW up to 375kW covered by the Ecodesign directive must meet minimum EU efficiency requirements of IE2 class when supplied by an inverter and IE3 when supplied DOL. 

Energimyndigheten subsequently analysed the motor’s performance in conjunction with four variable speed drives, which adjusted the output according to need by controlling the speed of the electric motor. 

If we define one efficiency class as 20 per cent less losses between two measures, the results showed how Dyneo® improves efficiency by an equivalent of one entire class better than Leroy-Somer's competitors’ products, and close to three efficiency classes above IE3 induction motors in the pump example. 

Compressor applications would give even higher differences as Dyneo® keeps its superior efficiency across the full speed and load ranges. 

The Dyneo® LSRPM motor from Leroy-Somer was tested both with a Unidrive M600 drive from Control-Techniques, and a model from one of Leroy-Somer's competitors. The optimized motor and drive package from Leroy-Somer clearly showed an improved efficiency, as a result of both drive and motor being engineered specifically to work together. 

The first example assumed a situation where an electric motor is supplied by a drive and used to drive a pump. The electric motor with the pump was installed in a system where there is constant pressure, but where the pump flow ranges from idling operation to the peak load. Under these conditions, the results show that in a year, this solution can save up to six per cent of the cost of electricity with a Leroy-Somer Dyneo® permanent magnet motor.

Electric motor systems are estimated to account for around 65 to 70 per cent of the total electricity used in industry, and almost 40 per cent of total global electricity use. They often run round the clock, throughout the year, and can be used to drive fans, pumps and compressors, or power systems such as elevators, escalators and large air conditioning or refrigeration units. 

It is estimated that more efficient electric motors could save around 135 terawatt hours (TWh) of electricity annually in the EU by 2020, more than Sweden's current total annual electricity use. 

Eric Coupart, from Leroy-Somer, said: “We wholly welcome the findings of the investigation, which confirms how Leroy-Somer drives and motor solutions, purchased as packages, deliver not only proven reliability but also the best return and life-cycle cost on the market.” 

The Swedish Energy Agency, which has been in operation since 1998, is the country’s national authority for energy policy issues. Its aim is a sustainable Swedish energy system, through the support of renewable energy, improved technologies, climate measures, and a smarter use of energy. 

Notes: 

The full results, including data and further analysis, can be found here (Swedish) 

www.energimyndigheten.se