It means that the voltage that supplies the motor has to be a direct current source.
A fan can use both voltages depending on what the manufacturer nameplates the motor voltage to be. AC is the most common voltage but some smaller fans like power supply fans in computers use a DC voltage. Check the fan motor's nameplate to supply the correct voltage.
It's the maximum mechanical power (either in horsepower or kilowatts) that the motor can deliver without overheating or overloading. You need to look at the nameplate (if it has one), or get the manufacturer's specs. It's difficult to know what the output is otherwise.
I've not heard the term "bressless" - I think you mean "Brushless" - which is a DC Motor that does not use the usual commutator/brush arrangement. For a great answer to this question, see the Wikipedia article in the related links section.
A DC shunt motor is a motor using DC supply with the the inductor connected parallel to the armature.
6V dc motor
A synchronous motor is an ac motor that does not run on dc.
A dc series motor can work on dc and ac because dc motors are totally reversible.
Yes it can and the otherway aroud a DC motor can be used as a dynamo
To state it simply, a DC brushless motor is not a DC motor. It is an AC motor with an inverter (or electronic commutator) on the front end to make the AC, so you can use a DC input.
the three phase dc motor never seen yet motor eaither 3phase m/r or dc motor.
dc series motor is used for traction...
what are the advanced applications of dc series motor