Some may assume that a dynamo and an alternator are the same, but actually, they are not. Dynamo is known to be a type of DC generator. The AC is known to be a type of AC generator. The Dynamo would need to have a commutator so that it will work while the alternator will not need to have this so that it can work properly.
A lot of people would choose the alternator for some of the projects that they may have because they think that the alternator is considered to be more reliable. The overall system of the Dynamo is considered to be less efficient as compared to the alternator. This is something that you can look into when you want to use motors.