Retrofit: rock tumblers into future-proof machines

“The outdated motors were energy guzzlers, but the drive system itself also consumed a lot of energy,” says Jos Hensen, industrial automation product specialist at itsme Breemes. “Indeed, speed control was still done with external resistors. So we knew for sure that the retrofit would give the customer a decent energy saving.”

Electric motor specialist AMR coordinated the project, itsme Breemes recommended the right variable speed drives. Siemens supported in the choice of components. Wouter Goris, sales engineer at Siemens: “This partnership allowed us to offer the customer the solution as one package and with one point of contact, but including the expertise of all three parties.”

The solution: energy-efficient IE4 motors and SINAMICS G150 drives

The retrofit was carried out in phases. Jos: “In 2023, it was the turn of rock tumbler number one, followed by numbers two and three in the following years. Each conversion took two weeks, including installation, testing and start-up, resulting in minimal interruption of production.”

Wouter: “The new powertrain consists of energy-efficient IE4 motors coupled with SINAMICS G150 drives. This combination ensures precise speed control, higher efficiency and lower energy consumption.”

To simplify maintenance and spare parts management, standardisation was chosen. With the exception of one heavier tumbler, all rock tumblers received the same type of motor and drive. Annelies: “The customer also invested in one replacement motor. Standardisation reduces the number of variants in spare parts, speeds up interventions and consequently reduces downtime.”

The technical challenge was water cooling in a dusty environment

A particular focus was the client's production environment. During glass grinding, fine, sharp particles swirl through the air, posing a major risk to ventilation-cooled drives. “Normal controllers use ambient air for cooling,” explains Wouter. “But in a dusty environment, those air ducts and fans immediately get clogged, risking overheating or damage.”

We therefore chose water-cooled drives in a closed circuit. This technology dissipates heat via water instead of air, increasing reliability and simplifying maintenance. “Water cooling was the only sustainable option,” Jos continues. “The customer has a constant water supply, and the system remains completely sealed off from the dusty environment. This way, we avoid having to constantly change filters and reduce wear and tear.”

The result: efficient, reliable and sustainable

The combination of IE4 motors and the G150 drives in a standardised arrangement provides noticeable energy savings and higher efficiency. After all, if one of the rock tumblers does come to a standstill, the spare motor can be deployed immediately. Wouter: “This way, the customer has much more control over the whole process. Emergency transports of spare parts—with all the associated stress for engineers—are definitely a thing of the past.”

The combination of energy efficiency, ease of maintenance and process reliability means the retrofit will pay for itself within a few years. Moreover, the plant is prepared for further digitisation, which adds to the long-term value of the project.

The next step: predictive maintenance with sensors

The collaboration between AMR, itsme Breemes and Siemens will continue with the implementation of predictive monitoring. “We are going to put sensors on the motors that measure vibration and temperature,” says Annelies. “This allows us to detect wear at an early stage and schedule maintenance checks before damage or downtime occurs.”

“Predictive maintenance fits within the Industry 4.0 approach that Siemens supports,” Wouter says. “It increases operational reliability, reduces energy loss due to bearing damage and enables more efficient maintenance planning. The first monitoring applications are planned for 2026.”

The retrofit has provided the insulation manufacturer with an energy-efficient, reliable and future-proof drive infrastructure. Jos: “We have provided our customer with an efficient and sustainable solution that is ready for a digital production environment.”