Drive/motor combo cuts extruder energy usage by 9%

Recently, Emerson Industrial Automation was able to help Stål & Plast, a Danish extrusion specialist, improve its production processes by replacing three worn-out dc electric motors with Dyneo PM motors and a Unidrive M variable speed drive at the company’s extruder plant.

Stål & Plast A/S of Denmark manufactures bench tray systems used in greenhouses and nurseries worldwide. The tray systems are manufactured on a fully automated vacuum forming machine. The raw plates are manufactured at a co-extrusion plant operated by three extruder motors, one 175 kW motor and two 71 kW motors. The extruder plant’s three worn-out dc motors were due for extensive reconditioning or alternatively an expensive and time-consuming replacement, as new dc motors would have to be made to order.

Jacob Braa Sørensen, managing director of Stål & Plast, in consultation with Emerson Industrial Automation, decided to upgrade the extruder plant by purchasing highly efficient Dyneo PM motors from Leroy Somer, which are controlled by a Control Techniques Unidrive M700 variable speed drive.

The replacement involved collaboration with service partners Lindpro as the professional installer and automation provider for the project, and Ølgod Elektro, which routinely handled commissioning and running-in.

For Stål & Plast A/S, the main reason for choosing a motor technology with permanent magnets was, first of all, the long-term energy savings on power consumption but also the higher operating torque, the operational reliability of PM technology and the low maintenance costs compared with dc technology.

Calculations showed that Stål & Plast could reduce the annual energy consumption of the three motors by an average of 9%. The extruder accounts for 75% of the plant’s total energy costs, of which most is consumed by the extruder motors.

Over a period of 10 years, 95% of the total costs of an electric motor are directly attributable to the energy consumption, whereas the purchase price and the maintenance costs represent as little as 5% of the total costs of the investment. when choosing the Dyneo PM motor technology from Emerson.