sarjamoottorit

Sarjamoottorit, also known as series motors, are a type of DC electric motor where the field winding is connected in series with the armature winding. This configuration means that the same current flows through both the field and armature coils. A key characteristic of sarjamoottorit is their high starting torque. This is because the magnetic field strength is directly proportional to the armature current, and at start-up, the armature current is at its maximum. Consequently, the torque produced is also at its maximum.

The speed of a sarjamoottori varies significantly with load. Under no-load conditions, the motor can reach extremely high speeds, potentially damaging itself if not properly controlled or protected. As the load increases, the armature current increases, which in turn strengthens the magnetic field. This stronger field leads to a decrease in motor speed. This inverse relationship between speed and load makes them suitable for applications where high starting torque is required and load conditions are expected to vary.

Common applications for sarjamoottorit include electric traction systems, such as in early electric locomotives and trams, where their ability to provide immense pulling power from a standstill is essential. They are also found in applications like electric hoists, cranes, and starter motors in internal combustion engines, although they have been largely replaced by other motor types in many modern applications due to their speed control limitations and the need for careful load management.