Classification of starters

Retarding starter

A starter with a gear reducer installed between the armature shaft of the starter and the driving gear is called a decelerating starter.

The power of the series DC motor is proportional to the torque and speed of the motor. It can be seen that when the engine speed is increased and the torque is reduced, the starter power can be kept unchanged. Therefore, when the series excited DC motor with high speed and low torque is used as the starter, the volume and weight of the starter can be greatly reduced under the same power. However, the torque of the starter is too low to meet the requirements of starting the engine. Therefore, when a high-speed and low torque DC motor is used in the starter, a gear reducer is installed between the armature shaft of the motor and the drive gear, which can reduce the motor speed and improve its torque.

Three forms of deceleration starter

The gear reducer of the decelerating starter has three different forms: external meshing, internal meshing and planetary gear.

For the external meshing reducer starter, the reducer uses the idler gear as the intermediate transmission between the armature shaft and the starter drive gear, and the magnetic switch core and the drive gear are in the same axis to directly drive the drive gear into engagement, without the need for a fork. Therefore, the appearance of the starter is quite different from that of ordinary starters. The transmission center distance of the external meshing reducer is large, so it is limited by the starting mechanism. Its reduction ratio cannot be too large, generally not more than 5, and is mostly used on small power starters.

Internally engaged decelerating starter, with small transmission center distance of decelerating mechanism, can have large reduction ratio, so it is suitable for starters with large power. However, the internal meshing type deceleration starting mechanism has a large noise, and the driving gear still needs to be engaged by shifting the fork, so the shape of the starter is similar to that of the ordinary starter.

The reduction mechanism of planetary gear type reduction starter has a compact structure. Large transmission ratio and high efficiency. Since the output shaft and the armature shaft are of the same axis and rotation direction, the armature shaft has no radial load and small vibration, so the overall size is small.

Permanent magnet starter

The starter with permanent magnet material as the magnetic pole is called permanent magnet starter. It cancels the excitation winding and pole core in the traditional starter, simplifies the structure of the starter, greatly reduces the volume and mass, improves the reliability, and saves metal materials.

Permanent magnet deceleration starter

The starter with a high speed, low torque permanent magnet motor and a gear reducer installed between the driving gear and the armature shaft is called a permanent magnet deceleration starter. The volume and mass of permanent magnet decelerating starter can be further reduced, and it has been widely used.