After earning his Master of Science in Engineering in 1960, Harmoinen began his career at Strömberg, a Finnish electrical engineering company that later became part of ABB. He remained with the same organization throughout his career - a testament to his loyalty and the transformative nature of the work he led. In recognition of his achievements, Harmoinen received the prestigious Finnish Engineering Award in 1981. Later, in 1995, President Martti Ahtisaari granted him the honorary title of Professor for his contributions to electric motor control systems. Harmonen's legacy is deeply rooted in Finnish innovation but at the same time has made a lasting global impact across different industries.
“I took the initiative on driving this technology forward. The AC drive was a risky project - that kind of technology didn’t exist at the time. We mastered it through systematic, persistent work. We realized that if we could develop speed control for the most common type of electric motor, the market potential would be enormous.” - Martti Harmoinen
Pioneering the LV AC drive: from idea to industry standard
The journey began with the challenge of enabling speed control for squirrel-cage induction motors - the most common type of AC motor used in industry. Working with his team, Harmoinen developed pulse-width modulation (PWM) technology, which made it possible to precisely control motor speed while improving energy efficiency. Before this innovation, an electric motor operated much like a car driven with the accelerator fully pressed and speed controlled using the brakes. The introduction of the variable speed drive meant smoother control, less wear and tear, and significant energy savings. This was a breakthrough for industrial efficiency!
In 1975, the SAMI A (Strömberg Asynchronous Motor Inverter Drive) was launched. That same year, the first commercial application - three SAMI A units at 350 kVA and 500 V - was delivered to the Karihaara sawmill in northern Finland. This marked a turning point: for the first time, the benefits of the technology were proven in a real industrial environment. With controllable motor speeds, the sawmill improved energy efficiency and reduced mechanical wear. In 1982, variable speed drives entered public transportation when they were installed in Helsinki's metro trains. That was a significant public milestone.
From there, the technology spread rapidly across sectors and continents, particularly as Strömberg became part of ABB in the 1980s. Today’s ACS series drives are a direct continuation of that development.
A legacy that powers the future
Martti Harmoinen passed away in April 2023 at the age of 88, but his legacy is alive in every application of drive technology around the world. At ABB, the spirit of Harmoinen’s engineering brilliance continues to inspire. Today, ABB is a global leader in variable speed drive technology. The LV AC drives business with its R&D and production units develops and manufactures low voltage drives and supporting software tools for all industrial applications, worldwid. Just as it was during the early days of Helsinki’s metro, we are responding to customer needs and ensuring reliability are at the heart of everything we do.
ABB is committed to helping industries become more competitive and sustainable. This is a mission we call Engineered to Outrun. Harmoinen's legacy is not just a milestone in engineering history, it is a living, driving force in ABB’s journey of innovation. The next chapter of the variable speed drive story is already being written by the next generation of engineers.
