Starters & Alternators

Starters & Alternators

Bosch explains why starters and alternators are the unsung heroes of an engine system.

Whether temperatures are below zero, or after a night on a truck stop next to the highway – no matter when or where, fleets need to be able to rely on engines starting up in order to meet the delivery deadlines. Accordingly, starters and alternators need to remain fully operational at all times – after all, the logistics sector very much depends on reliability. Therefore, the Bosch range for commercial vehicles includes powerful 12 and 24V starters, alternators, and spare parts.

24V starters

Bosch 24V starters stand out for their cold starting performance, caused by the design of their armature and stator housing. With their robust and compact design, these starters
remain protected against vibrations, dirt and water ingress. Both the sprocket and the starter pinion contribute to the reliability and long service life of these starters, and ensure that two-stage pinion engagement is safe and smooth. The modular starter concept means they can be efficiently adapted to the specific requirements of the respective commercial vehicle. For use in large engines or engines with additional hydraulic loads, Bosch has developed parallel-starter systems consisting of two or three linked starters. These systems start up diesel engines with up to 90L and gasoline engines with up to 180L of displacement.

12V starters

Similar to several other products, starter design is constantly being adapted and developed. Within the 12V range, for instance, four-pole multiple-circuit winding has led to an increase in the part’s performance.

Starter spare parts

In order to ensure a long service life, despite the heavy strains demanded of commercial vehicles, Bosch also provides a spare parts range. When carrying out a repair, technicians will have access to key spare parts that have passed functional tests in line with the same standard as the original equipment. These parts allow easy and quick starter repairs.

Engagement relay

Only high-quality plastics and metals are used for the engagement relay in order to ensure a long service life. Fully sealed engagement relays are available for special installation positions. All versions are said to feature switching reliability, and come with copper contacts and a specifically developed contact design.

Starter pinion with overrunning clutch

Due to their system with a special pinion geometry and engagement spring, Bosch starter pinions provide excellent engagement. Wear is reduced by improved greases and hardening processes, whilst particularly sturdy bearing bushes at the overrunning clutch also increase the service life.

Brush holder

The company’s starters are equipped with durable carbon brushes featuring a special material composition. To protect them against corrosion, they are placed into a holder made of plastic or coated metal. Coil springs achieve optimum brush pressure. In this way, the performance values remain consistent throughout the service life.


City buses, trucks, tractor units, crane trucks, vans and LCVs as vehicle concepts, are very
different, which means the performance requirements placed on HD commercial vehicle alternators are also very different. That’s what the Bosch range is made for. Its alternators are particularly robust and have a long service life, while the range comprises modules geared to the respective requirements. HD alternators, for instance, need to cope with high ambient temperatures. Therefore, they feature an enhanced ventilation system and high- temperature ball bearings. Whereas alternators that have to cope with extreme belt forces are equipped with reinforced end shields and larger A-ball bearings.

For more information on Bosch starters and alternators, click here.   

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