Predictive maintenance is the consistent continuation of condition monitoring with the aim of proactively maintaining the machines and systems and recognising changes, reducing downtimes and increasing the overall system effectiveness. Condition-based maintenance replaces traditional time-based maintenance.
Especially for drive systems in demanding industrial environments, for example in intralogistics, the food industry or industrial gear units in the heavy-duty sector, Condition Monitoring complements the triad of gear unit, electric motor and frequency inverter and improves safety and reliability, because industrial gear unit installations are usually used in sensitive applications whose failure can cause high damage. This is where condition monitoring for predictive maintenance comes into play: based on intelligent algorithms and software in conjunction with an IIoT environment, the networked drives can collect their condition data in the inverter's own PLC and pre-process it together with the data from connected sensors or actuators. The results of the pre-processing or the complete data are optionally transmitted to an edge device. There, the data of all subsystems are managed and evaluated. This data is then available as pre-selected and processed Smart Data for further use and clear visualisation.
Not just reading data, but analysing it
A concrete application example is the sensorless determination of the optimal oil change time on the basis of the oil temperature. This makes use of the fact that oil ageing in gearboxes is particularly dependent on the oil temperature. This information in combination with known gearbox parameters and specific, operation-related parameters enables a more precise indication of the oil change time. A physical temperature sensor is not required for this. The drive data is pre-processed in the integrated PLC of the NORD frequency inverter, which is used as the evaluation unit. The determined data can be made available to the customer via all common interfaces.
The right PLC software architecture for every solution
The equipment of the drive is optionally expandable and can be adapted to the respective automation task at any time. The customer can choose which tasks (drive monitoring, drive control, process control) he wants to transfer directly to the drive. This scalability gives him the opportunity, for example, to gain initial experience in a smaller production area before converting his entire plant. Three expansion stages are available. In the small version, the drive PLC only monitors the drive. The drive parameters are preprocessed in the PLC and forwarded to the higher-level plant control system, which is then responsible for drive and process control. In the medium configuration, the PLC additionally integrates the drive control and thus also executes drive-related functions. In the largest expansion stage, the inverter PLC completely replaces the higher-level system control. In addition to communication with a control system, local data management without an Internet connection can also take over the data if desired.