The armature winding is made by copper conductors insulated from each other and mounted in the grooves of the rotor and the torque at start of this type of motor is much better than the previous one because we can put resistors in series with the winding phases of the rotor. There are types in which the resistors are mounted on the rotor and eliminated, when the machine reaches its normal speed, through centrifugal mechanisms. In some types of motors, so that the brushes do not run out during normal running, they are suspended and the rings are short circuited by means of levers.
With the addition of rheostats in addition to improving the motor torque, we can vary the speed of the motor, but with the drawback of increasing the Joule loss in the resistors, alemite with best prices reducing their efficiency. Another type of coiled rotor is one in which its windings are attached to the collector rings on which the brushes rest. For these types we use rheostats, in star (Υ), connected in series with the windings of the rotor through brushes and collector rings. As the motor adds its speed, the rheostat is operated in order to gradually remove the resistors from the circuit until the star windings are connected.