01 · Cause
A capacity step that is too large
Fixed flow capacities and VSD control ranges need to fit together. Transitions between combinations matter too.
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Find control gaps.
Do your compressors’ flow capacities fit together? Check your station, identify critical transitions and compare new combinations directly in your browser.
Interactive station check
Does your station fit together?
Start with the example or enter your own compressors. Every change updates the result immediately.
Your compressors 2/16
Use flow capacities at the same operating pressure. Up to 16 compressors, including 2 with variable speed (VSD).
Results · live
The control range staircase
1 control gap found2–14 m³/min · available technical control range
Max. station flow14 m³/min
Largest control gap4 m³/min
These ranges have no matching combination
| From – to (m³/min) | Width (m³/min) |
|---|---|
| 6 – 10 | 4 |
The station has to cycle in these ranges. Consider smaller capacity increments or a suitably sized VSD control range.
Consider low load: Below 2 m³/min, demand is below the smallest controllable flow. This low-load range is shown separately and is not counted as an internal control gap.
The calculation includes all combinations of fixed-speed compressors and at least one active VSD. Actual switching times, pressure band, receiver volume and energy use are outside this capacity check.
Understanding control gaps
When the next step does not fit.
A control gap occurs when one combination cannot supply enough air and the next already supplies too much. Demand in that range cannot be met continuously.
02 · Effect
Frequent cycling
Within a gap, compressors cycle between load and idle. This can reduce efficiency and increase wear.
03 · Perspective
Coordination has its limits
Airleader can limit the effects by specifically cycling the VSD compressor. It cannot, however, compensate for unsuitable sizing.
Reading the chart
The staircase reveals the transitions.
- Blue steps
- The fixed flow supplied by the compressors currently included in the combination.
- Green areas
- The active VSD compressors supply the variable portion. Together with the blue step, they meet demand along the diagonal.
- Orange hatching
- This marks an internal control gap. The table below the chart lists its boundaries and width.
- Grey low-load range
- Below the smallest controllable flow, continuous VSD operation is not possible. This range is assessed separately from internal control gaps.