Torque is responsible for making the rotor of the electric motor is in operation and the torque is normally produced by the magnetic forces that lie between the magnetic poles of the rotor and the stator also.
The electric motor DC responsible for making the electric motor works are the magnets. It is essential that an electric motor DC count on some magnets that are classified electromagnets. Leeson 175310.00 FHP SERIES AC DRIV
If the DC electric motor is constructed with permanent magnets, the electric motor does not work, because the initial torque that causes the electric motor works not happen and even if the permanent magnet electric motor are in their equilibrium positions they just They suffered a small oscillation around the position where they are receiving a push something external to operate.