Spare Parts for John Deere Tractor ： 1000 2000 3000 Series
Spare Parts for John Deere Combine Harvester : 900 1000 Series
How was a Starter Drive works?
A starter drive includes a pinion gear set that meshes with the flywheel ring gear on the engine's crankshaft.To prevent damage to the pinion gear or the ring gear, the pinion gear must mesh with the ring gear before the starter motor rotates. To help assure smooth engagement, the end of the pinion gear is tapered. Also, the action of the armature must always be from the motor to the engine. The engine must not be allowed to spin the armature. The ratio of the number of teeth on the ring gear and the starter drive pinion gear is usually between 15:1 and 20:1. This means the starter motor is rotating 15 to 20 times faster than the engine. Normal cranking speed for the engine is about 200 rpm. If the starter drive had a ratio of 18:1, the starter would be rotating at a speed of 3,600 rpm. If the engine started and was accelerated to 2,000 rpm, the starter speed would increase to 36,000 rpm. This would destroy the starter motor if it was not disengaged from the engine