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#129049 - 07/06/04 12:01 PM * * * AC commutator motors* * *
nader Offline
Junior Member

Registered: 07/06/04
Posts: 1
Loc: bahrain
Please can show me by drawing who can I change the diriction of the AC commutator motors.

Thanks allot.

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#129050 - 07/06/04 12:39 PM Re: * * * AC commutator motors* * *
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
Hi Nader,

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).]

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#129051 - 07/06/04 01:24 PM Re: * * * AC commutator motors* * *
aland Offline
Member

Registered: 05/20/04
Posts: 187
Loc: United Kingdom
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.

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#129052 - 07/12/04 07:49 AM Re: * * * AC commutator motors* * *
khansami Offline
Junior Member

Registered: 07/08/04
Posts: 2
Loc: pakistan
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).]

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#129053 - 07/12/04 02:37 PM Re: * * * AC commutator motors* * *
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
But you can change the direction of rotation of an AC-fed universal motor if you go inside and reverse just the armature connections.

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