Drives in DC motors are usually the ones with the greatest benefits, also in terms of reliability, user-friendly operation and dynamic control Gates BX30 . On the other hand, this type of drive also has some disadvantages. The main objectives of the elements in an electrical panel are to protect the operator and to provide a command logic.
Concerning the disadvantages, DC motors are larger and more expensive than induction motors, for the same power, they have a greater need of maintenance because of the switches, because of the sparks due to the switching of current by mechanical element can not be hazardous environments. The voltage between blades can not exceed 20 v, ie they can not be supplied with a voltage greater than 900 v, whereas AC motors can have thousands of volts applied to their terminals, they need special starting measures, even on small machines.
The advantages are the operation in four quadrants with relatively lower costs, the cycle is continuous even at low speeds, high torque at start and low speeds, wide speed variation, ease of speed control, AC / DC drives require less space, high reliability and flexibility, relative simplicity of modern AC / DC converters.