Fifty years of VSDs — and we’re just getting started

VSDs work invisibly in the background, out of sight of consumers but crucial for industry. Today, they are embedded across water utilities, food factories, transport systems, data centres, and renewable energy projects, helping to make operations greener and more efficient. As we mark their half-century anniversary, it’s worth pausing to reflect on how this breakthrough changed the world, why it remains so critical today, and the possibilities it opens up for tomorrow.

The quiet revolution in motion control

Simply put, VSDs regulate the speed and torque of electric motors so that they run only as fast, and consume only as much energy, as they need to. Before the 1970s, the vast majority of industrial motors had just two states: on or off. For pumps, fans, compressors or conveyors, that meant operating at full tilt regardless of actual demand, leading to excess wear and unnecessary emissions.

The introduction of pulse width modulation (PWM) technology changed everything. It made it possible to finely control squirrel cage induction motors — the most common industrial motor, known for their simple, rugged rotor design — which had until then been restricted to running at full speed or not at all. PWM hailed a new era of motion, one defined by precision and responsiveness.

Early installations were pioneered by Martti Harmoinen, a lead engineer from ABB predecessor Strömberg who later received the Finnish Engineering Award in 1981. In 1975, he oversaw the implementation of the first commercially available VSD at the Karihaara sawmill in northern Finland, and their widespread use in Helsinki’s metro trains was soon to follow.

VSDs regulate the speed and torque of electric motors so that they run only as fast, and consume only as much energy, as they need to

These successes proved that motor efficiency did not have to be traded off against power. That same principle underpins modern drives, powering industries in every corner of the globe.

Impact measured in megawatts

While they operate out of sight and out of mind for most, the impact of VSDs is profound. Around 45% of the world’s electricity is converted by industrial motors into motion, powering everything from industrial production lines to air conditioning systems.

Fitting motors with VSDs allows operators to reduce energy demand by up to 30%, or even as much as 80% in certain applications. This also improves uptime and extends equipment lifespan.

In food and beverage plants, for example, VSDs ensure that pumps ramp up gently to reduce foaming in dairy processing, mixers apply torque with just the right consistency in bakeries, and conveyors handle bottles delicately during packaging. This precision guarantees high product quality, safety, and reduced waste — all critical advantages in food and beverage plants, where strict regulations and slim margins leave little room for error.

Equally important is reliability. Drives reduce mechanical strain by easing motors into action instead of subjecting them to hard stops and starts. Over time, the result is longer asset life and smoother operations. For industries under pressure to maximise output while minimising downtime, protecting operations from disruption can be as important as the electricity savings themselves.

Despite five decades of proven impact, adoption of VSDs remains low. Currently, fewer than 25% of industrial motors worldwide are paired with a drive, even though research suggests that applying VSD technology even to constant load equipment like pumps can yield energy savings of up to 12%.

Add in variable load applications like compressors, processed water systems, and HVAC systems, and the savings really stack up. If VSDs were widely applied to variable and constant load conditions, Europe alone could cut electricity use by around 140 terawatt-hours every year. That’s enough to prevent 38 million tons of carbon dioxide emissions annually, equivalent to powering five million homes for a year. This is why integrating VSDs across industries is one of the most practical, immediately deployable steps we can take to move closer to net zero. 

The next generation

Today’s drives aren’t just about efficiency; they also need to meet modern cybersecurity requirements. As part of connected industrial systems, drives must be secure by design to protect data integrity, uptime, and safety. ABB’s latest drives, such as the ACS380-E, embed security at both hardware and firmware levels – closing unused ports, verifying code at every start-up, and complying with the latest cybersecurity standards. With tools like these, drives contribute to layered defence strategies that help to protect connected factories from cyberattacks and disruption.

Despite five decades of proven impact, adoption of VSDs remains low. Currently, fewer than 25% of industrial motors worldwide are paired with a drive

Another pioneering technology is the Ultra-Low Harmonic (ULH) drive, which virtually eliminates the harmonic distortion that typically disrupts electrical networks. ULH drives not only safeguard equipment performance but also reduce energy losses and improve overall power quality. ULH drives raise the bar for how industries can operate more sustainably, securely, and efficiently.

At Orion’s pharmaceutical plants in Finland, Calefa has delivered heat pump systems that supply around 19,300 MWh of carbon-neutral heating each year. ABB’s ULH drives control the motors in these heat pumps, ensuring efficient performance and energy use. As a result, these systems cut emissions by 2,200 tonnes annually while supporting Orion’s goal of reliable, CO? free production.

The 50-year anniversary of the low voltage VSD is a moment to not only look back on a history of innovation, but also to look forward. In a world where electrification is accelerating and climate targets closing in, the adoption of energy efficient technologies is no longer up for debate. 

Fifty years on, the VSD continues to embody the principle of doing more with less: delivering the same performance while using less energy and producing fewer emissions. Its story illustrates that some of the most impactful technologies are often those most easily overlooked. But as we move into the next half-century, one thing is clear: VSDs will remain essential in industries that feed, power, transport, and cool our world. And this is only the beginning. 

Arnold Taddeo is head of global product management, ABB Drive Products

PIC: VSD pioneer Martti Harmoinen (inset Arnold Taddeo)