Austart ATS93 & ATS94 Turbine Air Starters – High-Output Compressed Air Cranking for Heavy-Duty Diesel and Gas Engines

The Austart ATS93 and ATS94 turbine air starters are high-output pneumatically driven cranking systems that channel compressed air through a precision turbine rotor, then step that high-speed rotational energy down through a three-planet epicyclic gear reduction to produce the sustained torque required to crank heavy-duty diesel and gas engines reliably in demanding field conditions. The ATS93 employs an inertia drive for automatic centrifugal pinion engagement, while the ATS94 uses a pneumatic piston pre-engaged drive that positively meshes the pinion with the engine ring gear before the turbine begins spinning. Both models are structured as three independently serviceable sub-assemblies — nose, motor, and silencer — and are engineered for continuous-duty use in environments where electrical starting is either impractical or presents an unacceptable ignition risk.

• High-Output Turbine-Driven Compressed Air Operation — Fully Spark-Free: The ATS93 and ATS94 operate entirely on compressed air, with no batteries, alternators, or electrical cabling in the starting circuit. This inherently spark-free design eliminates ignition risk in classified hazardous environments such as oil and gas wellheads, gas compression stations, fuel handling facilities, and underground mining operations — where electrical starting equipment must meet stringent explosion-proof certification requirements. Cranking torque remains consistent across the full operating pressure range from the standard 100 psi up to the 150 psi maximum, ensuring dependable engine starts even when air receiver pressure is not at peak level.
• Dual Drive Architecture: Inertia (ATS93) and Pre-Engaged Piston (ATS94): The ATS93 inertia drive harnesses the centrifugal force produced by the accelerating output shaft to extend the pinion along a helical spline into engagement with the engine ring gear, then automatically withdraws the pinion once the engine fires and its speed overtakes that of the starter. The ATS94 pre-engaged drive uses a pneumatically actuated internal piston to push the pinion positively into mesh with the ring gear before the turbine rotor begins spinning — guaranteeing full tooth engagement at the moment of peak cranking torque demand, regardless of air pressure fluctuations during the start cycle. This choice of drive architecture allows engineers to specify the mechanism best matched to each engine platform and application starting requirement.
• SAE 3 Flange for Broad Heavy-Duty Engine Compatibility: Both the ATS93 and ATS94 are built to SAE 3 flywheel housing standard, with a 3-hole bolt pattern on a 5.750-inch (146.1 mm) pitch circle diameter using Ø 21/32-inch holes equally spaced. This flange standard covers a broad range of heavy-duty diesel and gas engines across mining, marine, power generation, and industrial process sectors. The flange mounts directly and squarely to the engine flywheel housing, ensuring correct pinion-to-ring-gear alignment from first installation and maintaining that alignment throughout the service life of the starter.
• 360° Indexable Housing for Flexible Installation: The band clamp connecting the motor housing to the nose assembly allows the two sections to rotate continuously through 360 degrees relative to each other without separating the sub-assemblies. Loosening the clamp, rotating to the required inlet port orientation, and re-torquing to 4 ft lb (6 Nm) is all that is needed to redirect the air supply and control ports to the most convenient angle for hose and pipework routing. This adjustability is particularly valuable on engines where the flywheel housing area is restricted from certain directions, and allows the starter to be reconfigured in the field should installation requirements change without specialist tooling.
• Three-Planet Epicyclic Gear Reduction for Sustained Cranking Torque: Within the nose assembly, a three-planet epicyclic (planetary) gear set steps down the high rotational speed delivered by the turbine rotor to the lower cranking speed required at the engine ring gear, simultaneously multiplying torque to the level needed to turn over high-compression diesel and gas engines under cold-start and high-compression conditions. The three planet gears run on precision bearings within the spider hub assembly and are packed with lithium-based grease during assembly and scheduled servicing. This planetary gear train is the critical torque-multiplying stage that bridges turbine power and practical cranking performance.
• Integrated Silencer Assembly for Controlled Exhaust Noise: Each ATS93 and ATS94 starter includes a purpose-built muffler assembly that meaningfully reduces the discharge air noise generated when the starter exhausts at the end of each start cycle. The silencer uses stacked baffle plates and spacers retained by three through-studs and nuts that together provide progressive acoustic attenuation of the high-velocity exhaust airflow. Optional muffler and exhaust configurations — including threaded exhaust outlets — are available for installations with defined noise management requirements or where exhaust air must be directed rather than discharged freely to atmosphere.
• Three-Piece Modular Design for Efficient Field Servicing: Both starters are engineered as three distinct, independently serviceable sub-assemblies — the nose assembly (housing the drive mechanism, planetary gear train, and pinion), the motor assembly (containing the turbine rotor, rotor shaft, and bearings), and the silencer assembly — secured by two band clamps. Any sub-assembly can be removed, inspected, rebuilt, and reinstalled independently using standard workshop tooling including a hydraulic press and circlip pliers, without disturbing the remaining sub-assemblies. A genuine Austart service kit covering all seals, O-rings, piston rings, and bearings is available to support scheduled maintenance, restoring the unit to full factory specification at each service interval.