The Jetstream 5 air start motor is a pre-engaged starter motor capable of starting engines up to 80 litres. It's ideal for environments with explosive atmospheres (such as underground mines) as it is ATEX compliant.Find out more
Alongside traditional inertia starter motors, IPU can also provide pre-engaged starter motors for both air and hydraulic starting systems. Depending on your application, a pre-engaged starter motor could be the essential choice to comply with safety regulations such as ATEX.
The key difference between inertia and pre-engaged starting is that the pinion on a pre-engaged starter motor fully engages with the ring-gear before rotating at high-speed. Unlike traditional inertia starter motors there is no collision between a rapidly rotating pinion and a stationary ring-gear. This is a key factor when operating in a flammable environment.
The starter motor is fitted with a relay valve which controls the movement of the pinion. When the starter motor is activated the pinion moves along the shaft until it comes into contact with the toothed ring-gear.
The pinion is then interlocked with the ring-gear before rotating to crank the engine.
As the engine gets up to speed the pre-engaged starter motor is protected from overspeed by a free wheel clutch (like the free wheel gear of a bicycle). At this stage the return spring retracts the pinion to its disengaged position.
Watch our close-up video of a pre-engaged starter motor in action:
Pre-engaged starter motors are critical in areas covered by the ATEX safety regulations as any sparks caused by the starting system could be disastrous. IPU’s pre-engaged starter motors satisfy ATEX’s EN1834-1 and 2 safety standards as they eliminate the risk of sparks being generated by traditional inertia engagement.