January 2022

34 n VARIABLE-SPEED DRIVES January 2022 www.drivesncontrols.com VSDs help to get farm equipment manufacturer out of a scrape S torth Machinery is a slurry management company, located in Carnforth, that designs, builds and services automated scraping systems for farms. Its products include automated rope and chain scrapers that help to ensure hygienic conditions on farms. The company’s engineers faced two key challenges when developing the scrapers: detecting the end of a scrape; and sensing when the scraper encountered an animal or other obstruction. It called in Blackburn- based Ralspeed to help devise a control system that would incorporate both obstruction and end-of-lane detection. Together, they developed an cost-effective slurry system for cow houses that scrapes slurry safely into a channel, after which it is pumped into a storage and separation system. Ralspeed provided the know-how for the control panels as well supplying and installing the Vacon 20 AC drives that are at the heart of the system. An important benefit of these drives is that they can be configured to control four independent motors. “That means we could control two scraping lanes from a single drive,” explains Ralspeed’s technical director, Neil Parsons. This, in turn, helped to keep costs down. The flexibility of the drives allowed Ralspeed to devise a control panel that could be used with either chain and rope scrapers, and offered useful extra functions such as pre-programmable timing. The system has now been installed on hundreds of Storth scraper systems in the UK and abroad. n VSD control of slurry scrapers is helping farmers to clean their cowsheds cost-effectively