What PM VSD means
VSD is the variable speed drive: the motor speed follows air demand instead of running at a fixed rate. PM means the motor uses permanent magnets, which raises efficiency at part load and allows a more compact motor for the same output. Together they give a package that tracks demand closely across a wide range rather than cycling between loaded and unloaded.
The range in our catalogue
The PM VSD family covers models from 7.5 kW to 250 kW, with free air delivery from 1.2 to 13.4 m3/min depending on model, and working pressures of 7, 8, 10 and 12 bar. The right model is the one that sits near its design point at your average demand, not at your peak.
| Selection input | Why it decides the model |
|---|---|
| Average and peak flow | The average sets the operating point; the peak sets the maximum |
| Working pressure | Flow falls as pressure rises - compare at your real pressure |
| Voltage and frequency | 380/400/415 V 50 Hz and 220/380/440 V 60 Hz builds are available |
| Ambient | Rated to about 45 C; a hotter room reduces delivered flow |
| Air quality | Dryer and filter choice follows the process, not the compressor |
What part load really gives you
The economic case for VSD rests on how much of the year the plant runs below full capacity. If demand is steady at full output, a fixed speed machine at its design point can be marginally better because there is no drive loss. If demand swings - and in most workshops it does - the variable speed machine avoids the load/unload cycling that a fixed machine cannot escape.
Service points that matter
- Inlet filter - a restricted inlet costs efficiency immediately on a VSD machine because the drive tries to hold pressure by raising speed.
- Oil and separator - change on condition and schedule, not only on hours.
- Drive cooling - the VSD cabinet has its own cooling path; a dusty room shortens its life.
- Pressure sensor calibration - the drive controls to a measured pressure, so sensor drift becomes an energy problem.
Browse the range on the PM VSD with inverter compressor collection page.
Tell us the working pressure, flow and site conditions and we will propose a configuration. Contact OPPAIR.