
Air Motors & Mixers
GAST Air Motor 8AM-NRV-28A
The 8AM-NRV-28A is GAST's 3.7 kW (5 HP) flange-mounted, reversible 8AM air motor with a 2,500 rpm free speed, 21 Nm peak torque, 1/2" NPT ports and a 22 mm keyed shaft.
- Air
Powered - ATEX
Safe - Variable
Speed - Reversible
Explosion-Proof Power
for Hazardous Areas
The 8AM is the second-largest frame in GAST's AM range, delivering 3.7 kW (5 HP) at 2,500 rpm and 20.9 Nm of maximum torque. The -NRV-28A is a four-vane reversible unit with a flange mount and a 22 mm keyed shaft, intended for direct coupling to pumps, gear reducers and heavy mixers. The lower free speed compared with the 4AM and 6AM gives more usable torque without gearing.
Air consumption is 83 L/s at full load and 7 bar, so the motor needs a 1/2" supply line (or larger for runs over 2 m), a 5 µm filter and a lubricator. It can be stalled or overloaded continuously, is spark-free and cool running, and carries CE and ATEX II 2 GD c T4 marking for Zone 1 and 2 hazardous areas. An AG816 20:1 worm gear reducer is catalogued for the 8AM.
- Instant
Stall-Safe Torque - Cool
Running - Compact
Footprint - Long
Service Life

Technical Specifications
| Max power | 3.73 kW (5 HP) |
|---|---|
| Max speed (free) | 2,500 rpm |
| Torque: max / starting @ 5.5 bar | 20.9 Nm (185 in-lb) / 13.2 Nm (117 in-lb) |
| Torque at max speed | 14.9 Nm (132 in-lb) |
| Air consumption (max) | 83 L/s (5.0 m³/min, 175 cfm) |
| Air inlet / exhaust port | 1/2" NPT |
| Output shaft | Keyed, 22.35 mm (0.88 in) |
| Mounting | Flange (NEMA 56C type), operates in any plane |
| Rotation | Reversible (RV) |
| Lubrication | Lubricated |
| Max operating pressure | 7 bar (100 psi) |
| Weight | 12.7 kg |
Materials
| Body & End Plates | Cast Iron or Aluminium |
|---|---|
| Rotor | Steel, dynamically balanced |
| Vanes | Composite, self-lubricating |
| Shaft | Stainless Steel |
| Bearings | Sealed ball bearings |
| Muffler | Aluminium / sintered bronze |
Performance Curve
- 6.9 bar (100 psi)
- 5.5 bar (80 psi)
- 4.1 bar (60 psi)
- 2.8 bar (40 psi)
Dimensions
| Frame | Power (kW) | Length (mm) | Diameter (mm) | Shaft Ø (mm) | Weight (kg) |
|---|---|---|---|---|---|
| 1AM / 1UP | 0.03–0.1 | 92 | 58 | 8 | 0.8 |
| 2AM | 0.3–0.7 | 125 | 78 | 12 | 2.3 |
| 4AM | 0.7–1.3 | 180 | 100 | 16 | 4.5 |
| 6AM | 2.0–3.0 | 250 | 140 | 22 | 13 |
| 8AMthis model | 3.5–5.5 | 300 | 180 | 28 | 24 |
Typical dimensions for the model range; certified dimensional drawings are available on request.
Downloads
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