ristikkäiskäämitykset

Ristikkäiskäämitykset, also known as lap winding, is a type of winding used in DC electric motors and generators. It is characterized by the way the coils are interconnected. In a lap winding, the number of parallel paths through the armature winding is equal to the number of poles in the machine. Each coil is connected to adjacent commutator bars in a progressive manner. This means that as you move around the commutator, the coils are connected in a series of overlapping loops, forming a "lap" pattern.

The primary advantage of lap winding is that it provides multiple parallel paths for the armature current. This results in lower armature resistance and thus lower internal voltage drop, which can improve motor efficiency and generator output voltage regulation. Lap winding is particularly suitable for high-current, low-voltage machines. However, it also has a greater tendency to produce sparking at the brushes compared to wave winding, especially under heavy load conditions. The number of brushes required in a lap-wound machine is equal to the number of poles. The construction involves connecting the beginning of each coil to a commutator segment and the end of that coil to another commutator segment, with these segments being physically close to each other.