In modernization of large rotating equipment, one recurring challenge stands out: how to improve performance without adding unnecessary complexity? Although medium-voltage variable frequency drives ( MV-VFD ) were the default, they often led to substantial infrastructure extension requirements, heat management issues, and high maintenance demands.

Meanwhile, SET Sustainable Energy Technologies GmbH engineering teams believe efficiency should not be delivered with extra complications. That is why SETCON variable speed gearbox is becoming the technology of choice. With its compact low-voltage electronics, energy regeneration capabilities, and proven efficiency up to 97%, it offers a more streamlined path forward — the technically reliable and operationally simpler alternative. In this article, we explore why more and more clients are choosing SETCON as the smarter solution for retrofits.

Simpler Design, Lower Installation Requirements

Packaging size plays a crucial role in choice of a variable speed drive. Especially when a plant faces limitations of the existing spaces such as e-rooms. Large sizing of Medium-Voltage VFDs themselves (see grey zone at point 3 in the scheme below) may cause extra installation expenses for expansion of storage rooms. MV-VFDs demand bulky transformers (see gray zone at point 2 in the scheme) or integrated ones, complex safety measures, and specifically trained staff to handle the high-voltage electronics. This adds costs, implementation burden, and maintenance complexity.

Additionally, the choice of MV-VFDs leads to unavoidable modifications of the existing infrastructure in order to fit the new operating conditions. The new isolation criteria necessitate the installation of a new Main Motor when a MV-VFD is implemented. Furthermore, if a booster pump is in operation (connected to exchanged Main Motor) an additional Pony Motor is required, to maintain the constant input speed.

✔ SETCON, by contrast, uses low-voltage electrical components – standardized Frequency Converters and Control Cabinet (see point 2 in the scheme). The compact design minimizes space requirements and simplifies installation. Plus, in case of availability of a low-voltage supply source, the need of a transformer eliminates completely.

✔ As well, SETCON allows reuse of the existing constant-speed Main Motor (see point 1 in the scheme). The variable speed gearbox is adjusted to the operating conditions of the existing machinery, which significantly saves installation time and investments.

✔ Are you requiring a new Main Motor anyway? => You are still winning with SETCON. Thanks to the 20% power from SETCON Servo motors (see them in orange colour, point 1 in the scheme), a new Main Motor can be supplied in a smaller size for new business projects – 80% of total output power.

Heat & Energy Losses into Built-In Power Regeneration

MV-VFD systems inherently incur heat emissions, requiring constant large-scale AC room cooling systems or additional water supply to maintain cabinets’ operation.

✔ SETCON profits from its combined electro-mechanical design. Only 20% of the driven power goes through its air-cooled low-voltage Frequency Converters which leads to much lower losses in the cabinets.

✔ From the mechanical side, SETCON Servos, connected to a planetary gear stage, function as generators in partial loads, feeding excess energy back into the grid. This mode minimizes overall power consumption and operational expense. The gearbox offers up to 97% overall efficiency. Read more interesting facts about SETCON Planetary gear stage.

Smooth Maintenance & Serviceability

Diving into the safety of working environment, another critical advantage of SETCON variable speed gearbox is worth mentioning — serviceability.

MV VFDs require maintenance by highly trained, certified technicians due to high voltage hazards. A typical MV system demands monthly inspections, stringent lock out/tag out procedures, and annual overhaul by factory authorized specialists to ensure insulation integrity and safe operation.

✔ In contrast, SETCON contains familiar low-voltage architecture in Frequency Converters and Servo motors, allowing routine tasks to be performed by local maintenance teams after basic trainings. This dramatically reduces service response time, reliance on external contractors, and associated maintenance costs.

✔ SET notes as well the wide availability of the spare parts for the LV system. SETCON design includes standardized components from well-known suppliers.

🎯 Final Takeaway

SETCON outperforms MV-VFDs by:

• delivering equivalent or higher energy efficiency,
• eliminating complexity of electrical infrastructure,
• reducing cooling requirements,
• adapting to the existing infrastructure & minimizing modifications,
• enabling energy regeneration, and
• simplifying maintenance.

For operators seeking smooth, reliable, and cost-effective Drive Train modernization, SETCON is a compelling electro-mechanical alternative to medium-voltage VFDs — delivering highly competitive performance with long-term guarantees.

Below you can find a typical efficiency comparison between SETCON variable speed gearbox and MV-VFD with gearbox for a boiler feed pump application:

Rated Power: 6000 kW
Rated Speed: 5000 rpm
Speed Range: 50% - 100%
Operating time: 8500 h/year
Load distribution: see blue histogram

Average savings: 1400 MWh/year

Different parameters? Calculate your energy savings in the SET online app: https://set-solutions.net/setcon-savings/