Electricity and Control January 2021

DRIVES, MOTORS + SWITCHGEAR

High performance ac drives improve plant efficiencies

In the manufacturing industry, productivity means profitability, and plant managers need to reassess operations continually to get the most out of every day.When it comes to maximising plant efficiency, it is essential to consider how to improve the use of resources and decrease downtime through the use of ever-evolving industrial technology.The recent installation of ControlTechniques’ Unidrive M700 motor control system at a tyre retread manufacturer in Johannesburg, South Africa, has helped the plant improve performance, enabling the company to remain an industry leader.

B andag Southern Africa is part of the global Bandag group, a leading retread company which specialises in giving new life to truck tyres so they perform like new, but at a fraction of the cost. Specialising in truck fleets, new treads are applied to existing tyres to deliver more mile- age over any terrain using next-generation compounds that resist wear and tear. Around the world, almost nine million truck and bus tyres are fitted with Bandag retreads annual- ly, which makes the company an industry leader. Through a network of independent tyre franchisees in South Africa, Bandag SA has been providing a much-needed service to the African logistics industry since the 1960s. The company’s manufacturing facility in Alrode compris- es various multifaceted operations: from the processing of raw material, through to extruding, pressing, finishing, trimming, quality control and warehousing. First in this line of operations is the mixer – an enclosed automated mixing machine designed to break down rubber and other con- stituents into working-compound batches of about 220 kg each. This is an energy-intensive mechanical operation re- quiring consistent speeds and considerable force.

Existing technology reassessed Analogue dc drives were previously used in the mixer, but these became increasingly unreliable. Bandag then switched to Control Techniques Mentor MP digital dc drives – locally distributed by Nidec Automation – with the aim of maximising the motor performance and enhancing system reliability. “While this solution was an improvement, it was found to be energy-intensive and expensive to maintain. Aside from the costs, continuous maintenance required plant down- time which hindered production efficiency,” says Bruce Grobler, Regional Manager of Nidec Automation. “A new solution was clearly needed. To solve the problem, Bandag SA relied on its trusted and longstanding relationship with our valued partner, Multispeed Transmissions,” Grobler says. Led by Jim Fraser, Multispeed Transmissions has been working with Bandag SA for over 20 years, ensuring that its manufacturing facilities are fitted with the most suitable solutions for the tasks at hand, helping them to remain visionaries in the retread industry. Having previously installed Control Techniques ac drives on the plant’s extruder and calendar mill (a process that forms the exudates and processes cushion gum), Fraser concluded that the mixer operations would also benefit from a similar installation. Bandag SA Manufacturing Director, Jonathan David says, “Jim came to us with this idea, and we couldn’t fault it. We had seen great successes on the previous installations on the extruder and calendar mill and it was a simple de- cision to roll this out on the mixer. Our proactive executive team was quick to back the idea.” Grobler comments: “We were delighted that Jim decid- ed to again use Control Techniques’ drives in the plant. Our innovative and reliable technology has proven itself in sim- ilar operations, positioning our high-performance drives as the solution for this application.” Improved operations Fraser selected Control Techniques’ Unidrive M700 ac drive, a high-performance motor control system providing optimum control flexibility in high specification industrial

Control Techniques’ Unidrive M700 motor control system was selected to improve productivity and performance efficiencies at the Bandag tyre retread plant in Johannesburg, South Africa.

12 Electricity + Control JANUARY 2021