What are the main diferences between an AC and DC motor. i understand the difference in wave form in the two differect supplies but are there any clear diferences between the motors and how they work?
dc type can usually run in higher speeds, its control is very simpler, but its mechanical structure is more complicated and it degrades faster than ac type
ac type has simple and rigid mechanical structure, works in lower speeds, and its control is more complicated.
b.zahedi is correct. if you need high speed and bigger moment you choose DC motor but Its price is expensive. AC motor is cheaper and to have bigger power.