Brushless DC Motor Controller - Reverse Direction

Hi all,

Can a brushless DC Motor Controller be used in reverse direction.
Can it be supplied with an AC input and to generate a DC output... is
that possible at all or am I being really silly !

Radil

 

I have seen some forum discussion in which this happened.. but can I
have an explanations of basics of how this Brushless motor controller
actually works and is it possible that it can run the other way

 

Hmm.
Brush less DC motors are actually AC motor's in nature.
depending on the design, they usually have a Delta type
stator. An optical position index array so that the drive
and monitor it's position between fields.
some have PM in the rotors, some don't.
the controllers can actually fix lock the shaft if it
wishes, due to the quaddr sensor array, it can act very
smoothly move the shaft in any direction with in a degree
of stability..
they use these motors for long service life and synchronization
with other moving parts of machines.
The one's with the PM do get weak over the years due to the
heat on the rotor breaking down the PM. when this happens, slipping
starts to take place and timing is out of whack. what we do is increase
the current in the fields to make up for it, which just adds to the
problem because more heat them builds up. This last for a few months
this way. then we finally get around to pulling the motor and sent it
out for rebuild..
These motors are not cheap, we 10 Hp Brush less motors that cost 12K
each.