Electric Motor Demostration 2 pole, 3 pole, 4 pole Aramtures. A model of the simplest form of DC electric motor. Three armature, 2 pole, 3 pole and 4 pole, Wound with enameled copper wire and a permanent magnetic field provided by a removable bar magnet. A disc-type commutator is incorporated and external connection to the phosphor-bronze bushes is by means of a pair of 4 mm sockets. Operates on 4.5 - 9 Volts DC.