75 kW Direct-Drive VFD Compressor for an Environmental-Equipment Maker

The client is a manufacturer of environmental technology equipment. Its production processes place higher demands on compressed air than a typical workshop. The plant did not just need “a compressor”; it needed an air system that would:

• run efficiently and respond quickly to changes in demand;
• sustain long hours at high load while keeping energy consumption under control;
• deliver stable, clean air without disturbing sensitive components in its products and test equipment.

The plant’s air demand fluctuates during the day, and production typically runs for more than ten hours daily. Under those conditions the unload losses of a fixed-speed, belt-driven machine add up quickly.

Equipment: The plant installed a 75 kW SIND SILVERLUBE-VPM series permanent-magnet variable-speed screw compressor with direct drive:

• Direct drive. The motor and airend share a common shaft, with transmission efficiency above 98%. This avoids the slip and wear losses of belt drives and reduces vibration.
• Variable-speed control. Motor speed follows real-time air demand, which avoids frequent load/unload and start-stop cycles and cuts idle consumption.
• Industrial-duty design. A robust airend and high-efficiency PM motor are built for long, continuous operating hours.
• Easy integration. The compressor connected to the plant’s existing air network and exhaust-gas treatment system without major modifications.

• Smooth, low-vibration operation, with stable supply pressure for production and test equipment.
• Lower electricity costs, clearly visible at more than ten operating hours per day.
• Up to 35% expected energy saving compared with a conventional fixed-speed, belt-driven compressor.
• No major changes needed to the existing air or exhaust-treatment systems.