Operating at normal power line frequencies, universal motors are often found in a range less than 1000 watts. Universal motors also formed the basis of the traditional railway traction motor in electric railways. In this application, the use of AC to power a motor originally designed to run on DC would lead to efficiency losses due to eddy current heating of their magnetic components, particularly the motor field pole-pieces that, for DC, would have used solid (un-laminated) iron and they are now rarely used.
What is the typical maximum range of universal motors? What type of motor was used in trailway traction applications? What is the result of using AC power on a DC motor? What were universal motor pole pieces constructed from?