Startergeneratoren

Startergeneratoren, often referred to as starter generators in German-speaking contexts, are electromechanical devices that perform two roles in a single unit: they start an internal combustion engine as a motor and, once the engine is running, they operate as a generator to supply electrical power and charge the battery. This combination aims to simplify installation by reducing the number of components and wiring.

In operation, the unit is typically belt-driven from the engine. During starting, the machine draws current from the battery and drives the crankshaft to bring the engine up to speed. After ignition, the device is switched or reconfigured to run as a generator, with the crankshaft driving the machine to produce direct current. The generated electricity is regulated to a charging voltage by adjusting the field current or using a control circuit. Most startergenerators are brushed DC machines with separate or permanent-magnet field windings; some designs use electronic controls to manage the transition between motor and generator modes.

Applications and history: Startergeneratoren were widely used in early automotive designs and in some marine and stationary engines as a compact solution for starting and charging. Over time, many systems migrated to dedicated starters and separate alternators (or alternators coupled with modern electronic controls), offering greater efficiency, reliability, and control. Today, startergenerators survive in niche applications, such as certain small engines, specialized equipment, or retrofits, where their compact, combined functionality remains advantageous.