Commutators are found on DC motors, not AC (although you could include the "universal" AC/DC types as are found in some appliances).
You can reverse the direction of rotation of such a motor by swapping the connections to the armature (i.e. those connections which go via the commutator) while leaving the field connections unchanged, or vice versa.
If it's a small permanent-magnet motor (which has no field coil) then just reversing the connections of the DC supply will suffice.
[This message has been edited by pauluk (edited 07-06-2004).]
Yes you can have Commutators on A.C. Motors, Not so very common now in the age of the inverter. Mostly used for variable speed aplications where the brush gear is driven around the comm to effect speed change. Commonly known as Schrage motors. If its a three phase motor just change two phases as you would a normal induction motor. Beware if it has an electrically driven pony motor to drive the brush gear you may have to seperate the supply to the pony motor to prevent that from reversing as well.
Re: * * * AC commutator motors* * *#129052 07/12/0409:49 AM07/12/0409:49 AM
AC commutator motor we called it universal motor as it can run on both voltages AC & DC. In case of DC voltage U can change direction of motor by revrsing supply connection,But in case of AC voltage U can not change direction because AC voltage alternates its voltage and current so reversal of current can not be achive in armature and field.
[This message has been edited by khansami (edited 07-29-2004).]