34 n VARIABLE-SPEED DRIVES January 2026 www.drivesncontrols.com Unlocking the untapped potential of inverters For many operations, adding a VSD is the first step in a journey towards automation, efficiency and improved control. It regulates the speed and torque of a motor to match the demands of the process, rather than running constantly at full power. However, in our experience, the benefits of that first step are often under-appreciated. When set up properly, an inverter doesn’t just provide speed control for a motor – it also allows the current, torque, power factor and ramp-up profiles to be fine-tuned. The result? Better motor performance, lower start-up currents and reduced wear-and-tear on equipment. However, if a VSD is left running on its out-of-the-box parameters, those benefits can be lost. Let’s take a closer look at what a good setup looks like – and what can happen if this is overlooked. Stalling Most VSDs are pre-configured for variablefrequency control, which suits variable torque loads such as fans and pumps – applications where less torque is needed as the speed decreases. However, this set-up isn’t suitable for constant-torque loads, such as conveyors or elevators, where the weight of the material stays the same regardless of the speed. In these cases, the motor still needs to deliver full torque even at low speeds. If variable-frequency control is used in these situations, the drive reduces the voltage along with the frequency, limiting the available torque. This can lead to stalling and inefficient performance when the motor is under heavy load, but running slowly. The key is to use the drive’s sensorless vector or flux vector mode. This is a form of openloop control that enables high torque production even at low speeds, without needing extra encoder hardware. When configured correctly, it delivers full torque from 5Hz upwards, making it ideal for demanding applications such as feeders, crushers or conveyors under heavy load. One good example of the value of a correct set-up occurred at a Kerry Agribusiness feed mill in County Kerry, Ireland. The mill’s feeding system, which delivers raw materials into the grinders, previously relied on manual speed adjustments. Operators used experience and trial-and-error to find the right settings – a method that often led to inefficiencies. When speeds were too low, throughput dropped. When they were too high, the material wasn’t milled properly, affecting its quality. Technidrive replaced this with an automated feeder control system using a WEG CFW11 frequency inverter. Configured in sensorless vector control with a tailored feedback loop, the system adjusts the feeder speed automatically based on real-time conditions. The result was a 29% increase in throughput and far fewer manual adjustments. A common mistake is using the wrong control mode for the load. For example, a conveyor left in default V/f mode can lose torque at lower speeds and risk stalling – a serious issue in feeders running under constant load. Another pitfall is assuming slower always means more efficient. While reducing speed can save energy, this only works if the load is monitored and the system adjusted properly. A better approach is to use the VSD’s current-sensing capabilities to adjust the speed dynamically. If a belt is under-loaded, the speed can be reduced; if it's heavily loaded, the speed can increase. In some projects, we have used PID (proportional integral derivative) loops to adjust motor speeds based on load feedback from the VSD itself. No extra sensors or hardware are involved – just smarter use of existing data. Web interfaces As inverter technology evolves, so does the scope of what’s possible. Modern drives include Web interfaces, opening up possibilities for data-driven maintenance, optimisation and energy management – without adding any new hardware. We have seen countless examples where a smarter inverter set-up has delivered results. In one case, a customer fitted a VSD purely to reduce start-up current on a conveyor, but didn’t realise it could also be used to control the belt load and energy usage. Once we explained the potential, we helped them implement a load-based feedback loop using only the existing drive. Again, no extra sensors, just a better set-up. Demand for automation, performance and energy efficiency is on the rise – and inverters are key to delivering all three. A VSD running on default settings may work, but it won’t optimise your system. With the correct configuration, you can achieve smarter control, higher efficiency and a stronger ROI – and unlock that hidden potential. n The full capabilities of VSDs are often overlooked. David Strain, technical director at the automated systems specialist Technidrive, explores the untapped possibilities inside every inverter that can unlock performance and energy efficiency. A properly set up inverter can unlock untapped potential in conveyors and other applications where current, torque and power factor present challenges.
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