or if a DC Motor is connected on a AC source???
as the other answers state, the AC motor would just lock up and eventually overheat or destroy the power source! The DC motor however may be fine. If the rotor and field windings are BOTH excited by the power suply, then a DC motor will work normally with AC power. This is because as the current changes direction, both the rotor and stator would swap also, and the overall effect would be the same, meaning the motor would turn normally! many cheap AC motors have commutators and brushes, and could run perfectly well from a suitable DC supply
3ph AC connected to DC: It will get hot and smoke, it won't rotate. DC motor to AC source: It will get hot, smoke and vibrate - it also won't rotate.
I would also have said no such thing, but have realized I don't know everything, or even what I thought I knew (thanks, Google) It seems the rotor of a DC 3-phase motor consists of permanent magnets while the rotor of an AC motor consists of windings, at least for the examples I found.
ac= you would saturate the coils and the motor would become a big magnet (locked up)
An AC only motor connected to DC would do nothing, or just lock, or worse just burn out. A DC motor only motor connected to AC to just hum and its shaft just go back and forth a bit.
