Pacinotti dynamo

These early designs had a problem: the electric current they produced consisted of a series of "spikes" or pulses of current separated by none at all, resulting in a low average power output. As with electric motors of the period, the designers did not fully realize the seriously-detrimental effects of large air gaps in the magnetic circuit., an Italian physics professor, solved this problem around 1860 by replacing the spinning two-pole coil with a multi-pole one, which he created by wrapping an iron ring with a continuous winding, connected to the commutator at many equally spaced points around the ring; the commutator being divided into many segments. This meant that some part of the coil was continually passing by the magnets, smoothing out the current.