Savings From Improved Torque Ratio & Efficiency

Production at Regain Polymers of Castleford, West Yorkshire, is based on seven extruder lines. As part of its programme to cut energy use and carbon emissions, it identified one of its extruder lines as a prime candidate for improvement. This was based on a 400kW DC motor and the company wanted to convert it to AC operation. As well as the expected energy savings, the conversion to AC would eliminate the need to replace the DC brushes every three months, saving £2500 a year.

Regain Polymers asked ABB Drives Alliance member Quantum Controls to investigate the extruder for possible conversion to AC. A data logger installed by Quantum established that the daytime electricity costs for the DC motor were £424.

Quantum fitted a 400 kW ABB AC 4 pole squirrel cage motor and variable-speed drive, together with new mains cable. Following installation of the AC motor and drive, energy costs dropped to £260 a day, a saving of around £163 based on a 24 hour a day production.

With 300 days total production a year, this would give a total annual saving of £49,000. This would be an energy reduction of nearly 870,000 kWh per year, as well as saving over 488 tonnes of CO2.

The AC motor runs at the same speed as the previous DC motor, with savings coming from the improved torque ratio and efficiency of the AC drive and motor.