Rotary Screw Compressor
HankeMotor stocks oil-injected rotary screw air compressors for industrial and workshop applications requiring continuous, reliable compressed air. Unlike piston (reciprocating) compressors, rotary screw units run at 100% duty cycle — they can operate non-stop without rest periods or overheating. All units are dispatched from our Glen Waverley, Victoria warehouse.
Screw vs Piston: Which Compressor Fits Your Duty Cycle?
The choice comes down to how long your compressor runs per hour:
| Rotary Screw | Piston (Reciprocating) | |
|---|---|---|
| Duty cycle | 100% continuous | 50–75% (needs rest periods) |
| Noise level | Lower (60–75 dB typical) | Higher (80–90 dB typical) |
| Air quality | Consistent, low pulsation | Pulsating air delivery |
| Maintenance | Oil change every 2,000–4,000 hrs | More frequent valve and ring service |
| Best for | Spray booths, CNC, production lines, large workshops running all day | Intermittent use, small workshops, lower budget |
| Power input | 415V three phase (most models) | 240V single phase or 415V three phase |
Rule of thumb: If your compressor runs more than 40 minutes per hour, a rotary screw will cost less to run and last longer. If it runs 20 minutes per hour or less, a piston compressor is more cost-effective for the initial purchase.
Selecting the Right Screw Compressor
Size by free-air delivery (FAD) in CFM or L/min — not by motor kW. The CFM rating must exceed your total tool demand at the operating pressure you need (typically 7–10 bar / 100–145 PSI for workshop use).
Common matching guide:
- Spray painting booth — minimum 20 CFM at 6–8 bar, plus headroom for continuous operation. A single HVLP spray gun draws 6–14 CFM.
- CNC machining centre (spindle air blast) — typically 15–40 CFM depending on tool change and coolant systems.
- Sandblasting — 50–100+ CFM for production blasting. Under-sizing causes pressure drop mid-job.
- General workshop (multiple air tools) — add the CFM of all tools likely to run simultaneously, then add 25% margin.
All rotary screw models in this range require 415V three-phase power supply. If you have single-phase 240V only, see the piston air compressor range.
Installation Requirements
Rotary screw compressors generate heat during operation and require adequate ventilation. Key installation requirements:
- Minimum 500mm clearance on all sides for airflow and service access
- Ambient temperature between 0°C and 40°C for correct operation
- Isolated concrete pad or anti-vibration mounts to reduce structure-borne noise
- Discharge air temperature from the compressor is high — allow the aftercooler to drop temperature before connecting a refrigerated air dryer
- Three-phase 415V electrical supply sized to the compressor's full-load amps plus 25% service margin
Do rotary screw compressors need a receiver tank?
A receiver tank is recommended even for rotary screw units. The tank acts as a buffer for demand spikes, reduces short-cycling of the load/unload system, and provides storage for the refrigerated dryer to work against. Minimum tank sizing: 10 litres per CFM of compressor output.
What is the service interval for an oil-injected screw compressor?
Oil change and filter service typically occurs at 2,000 to 4,000 operating hours depending on the manufacturer and operating conditions. Separator filter, oil filter and air filter are replaced at the same service.
For stock availability, pricing, or application advice: 0401 634 280 | hankemotors@gmail.com | Unit 1, 28 Aristoc Road, Glen Waverley VIC 3150.
Related: Refrigerated Air Dryers | Piston Air Compressors | Air Compressor Pumps