Forklift Starters and Alternators - A starter motors today is usually a permanent-magnet composition or a series-parallel wound direct current electrical motor along with a starter solenoid mounted on it. As soon as current from the starting battery is applied to the solenoid, mainly via a key-operated switch, the solenoid engages a lever which pushes out the drive pinion that is located on the driveshaft and meshes the pinion utilizing the starter ring gear which is found on the flywheel of the engine.
When the starter motor starts to turn, the solenoid closes the high-current contacts. When the engine has started, the solenoid consists of a key operated switch that opens the spring assembly to pull the pinion gear away from the ring gear. This particular action causes the starter motor to stop. The starter's pinion is clutched to its driveshaft by means of an overrunning clutch. This allows the pinion to transmit drive in only one direction. Drive is transmitted in this particular way via the pinion to the flywheel ring gear. The pinion continuous to be engaged, for instance since the driver did not release the key when the engine starts or if the solenoid remains engaged in view of the fact that there is a short. This actually causes the pinion to spin independently of its driveshaft.
This aforesaid action stops the engine from driving the starter. This is actually an important step since this particular type of back drive will allow the starter to spin so fast that it could fly apart. Unless adjustments were made, the sprag clutch arrangement will prevent using the starter as a generator if it was used in the hybrid scheme mentioned earlier. Usually an average starter motor is intended for intermittent use that will stop it being used as a generator.
Hence, the electrical parts are designed to function for about less than thirty seconds to avoid overheating. The overheating results from very slow dissipation of heat because of ohmic losses. The electrical components are meant to save cost and weight. This is truly the reason most owner's instruction manuals meant for vehicles recommend the driver to pause for at least ten seconds right after each and every ten or fifteen seconds of cranking the engine, when trying to start an engine that does not turn over immediately.
The overrunning-clutch pinion was launched onto the marked during the early 1960's. Prior to the 1960's, a Bendix drive was used. This drive system works on a helically cut driveshaft that consists of a starter drive pinion placed on it. When the starter motor begins spinning, the inertia of the drive pinion assembly allows it to ride forward on the helix, thus engaging with the ring gear. When the engine starts, the backdrive caused from the ring gear allows the pinion to exceed the rotating speed of the starter. At this point, the drive pinion is forced back down the helical shaft and thus out of mesh with the ring gear.
During the 1930s, an intermediate development between the Bendix drive was developed. The overrunning-clutch design that was made and launched during the 1960s was the Bendix Folo-Thru drive. The Folo-Thru drive consists of a latching mechanism together with a set of flyweights inside the body of the drive unit. This was an enhancement in view of the fact that the average Bendix drive used to be able to disengage from the ring as soon as the engine fired, although it did not stay running.
The drive unit if force forward by inertia on the helical shaft when the starter motor is engaged and starts turning. Then the starter motor becomes latched into the engaged position. Once the drive unit is spun at a speed higher than what is achieved by the starter motor itself, for instance it is backdriven by the running engine, and then the flyweights pull outward in a radial manner. This releases the latch and enables the overdriven drive unit to become spun out of engagement, thus unwanted starter disengagement can be avoided before a successful engine start.
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