What kind of layer winding does a closed winding of an electric machine usually have?

In electric machines, a closed winding typically refers to a type of armature winding where the end of each coil connects to the start of another coil in a continuous loop. This form of winding can be further categorized into two main types: lap winding and wave winding. Both of these are employed in the design of electric machines like DC motors and generators based on the specific application requirements like voltage, current, and performance efficiency.

– Lap Winding: In lap winding, each coil overlaps the next, so the end of one coil connects to the beginning of the next on the same armature. This results in several parallel paths in the armature circuit, making it well-suited for high-current, low-voltage applications because it allows for more effective current collection.

– Wave Winding: Wave winding, on the other hand, arranges the coils in series, extending around the armature in a wave-like pattern. This type of winding only has two parallel paths regardless of the number of poles. Wave winding is typically used for high-voltage, low-current applications since it enables a greater number of turns in each coil, enhancing the induced voltage.

Both lap and wave windings are examples of closed windings because their design ensures that there is no open end in the circuit; the last coil is always connected back to the first, forming a closed loop. This ensures the efficient operation of the electric machine by facilitating a continuous path for the current to flow.