M22 Pre-engaged Hydraulic Starter Motor

IPU’s M22 pre-engaged hydraulic starter motor provides guaranteed reliability, no matter how challenging or unpredictable the environment. IPU’s M22 and M28 hydraulic starter motors are unique in achieving ATEX-approval for use in both gas and mining environments. Compliance with ATEX means they are safe for use in explosive and potentially explosive applications.

starting approvals

The M22 hydraulic starter motor is ATEX-approved. IPU’s starting systems are also certified to many other standards.

Marine class approval

IPU’s starting systems can be class approved to numerous marine certification standards. This is done on a case by case basis according to specific customer specifications.


Cast iron casing

IPU’s starter motors are manufactured with a cast iron outer casing. This is due to the ATEX regulations strongly discouraging the use of aluminium in mining and other explosive environments. This is because aluminium is a key ingredient in a thermite reaction and such a reaction in an explosive environment would be catastrophic!

Unfortunately, many aluminium-cased starters are still sold into mining environments despite the ATEX recommendations. This falls short of the safety standards and is inherently dangerous.


A pre-engaged starter motor

Traditional ‘inertia’ starting has the possibility of producing sparks when the rapidly spinning pinion engages with the engine’s stationary ring-gear. ATEX regulations require starter motors to be ‘pre-engaged’. IPU’s pre-engaged M22 starter motor fully engages the pinion with the ring-gear before rotating at high speed.


Non-spark pinions

The M22 is also available with a beryllium-copper pinion to further reduce the risk of sparks. This is an optional safety precaution over and above the protection offered by the pre-engaged system.


Flexible to suit any engine configuration

The orientation of the M22 can be rotated to suit your engine configuration. This is achieved by rotating the flange of the standard model. If the configuration is particularly difficult IPU can provide a custom flange to suit.


m22 pre-engaged hydraulic starter

Power curves for IPU’s M22 pre-engaged hydraulic starter


Simple maintenance

The M22 pre-engaged hydraulic starter motor is a low maintenance solution that’s reliable in all conditions, including sub-zero and high temperature environments. It requires virtually no attention other than replacing the filter element and periodically checking the gas pre-charge and system pressure.

Parts such as spacers, flanges and pinions used on the M22 are also common to IPU’s air starter range. This helps remote and offshore sites simplify stock-holding and improve interchangeability.


M22 pre-engaged hydraulic starter specifications

Weight (typical) 12 kg
Construction Cast iron
Maximum working pressure 21 MPa (3000 PSI)
Fluid media Mineral oil
Viscosity range ISO 32 to 46 (SUS 140-230)
Temperature range -30°C to +100°C (-22°F to +212°F)
Speed range 0-4000 rpm
Rotation Standard: Clockwise (Optional: Counter-Clockwise)
Duty cycle Intermittent
Overall volumetric efficiency 92% (Minimum)
Displacement 22.1 cc (1.35 cu.in.)
Maximum torque at 210 Mpa (1500 psi) 66 Nm (49 lbf.ft.)
Maximum power at 3500 rpm 24 kW (32 HP)


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