On 7/14/05, Augusto Yipmantin <augustoy@centaurocomunicaciones.com> wrote=
:
> Thank you for the reply to all.
> The motor schematic is as follows:
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>          +--00000000----+
> A 0------!              !
>          +--00000000--+ !
>                       ! !
>                 +-----+ !
>                 !     ! !
>     150uF50V   =3D=3D=3D    ! !
>                 !     ! !
>                 +-------+
>                       ! !
> B o-------------------+ !
>                         !
> C o---------------------+  =20
> =20
> 48VAC to A-B the movement is CW
> 48VAC to A-C the movement is CCW
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> The motor speed gives me one turn of the antenna each two minutes.
> What I need is one turn in 5 minutes.


  I've seen a pseudo speed controller for this kind of motor into a
washing mashine,
the rotor is squirell type, apply on A or B terminals a small pack of
sinusoidal alternaces. The PWM resulted with a duty cycle determined
by the number of the ON alternaces pack and the OFF alternaces pack
will gave you a quite precise control of the rotation and will
decrease considerably the power on the motor shaft.
So the gear will be essential. Do not try with only one alternace of
the main because the false phase shifter (the capacitor) required for
rotation will cry. The minimum ON pack must have at least 5...10
complete sinusoide while the OFF could be much longer.

A true Matsushita inverter with 10Hz-150Hz control will be probably
too expensive
(about 150$).


Vasile






> This will give me more precision pointing the antenna, the reduction of
> the velocity never can be variable, it must be fixed.
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> The rotor is a CDE Ham IV, and has some gears to reduce the motor=B4s
> velocity.
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> Regards,
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> Augusto
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> -----Mensaje original-----
> De: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] En nombre
> de Vasile Surducan
> Enviado el: Jueves, 14 de Julio de 2005 12:39 p.m.
> Para: Microcontroller discussion list - Public.
> Asunto: Re: [OT] How to reduce velocity of AC Motor
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> On 7/14/05, Augusto Yipmantin <augustoy@centaurocomunicaciones.com>
> wrote:
> > Hi all,=20
> >=20
> > Maybe this will be a fool question, but I want to know how to reduce
> the
> > velocity of a 48VAC little motor used by HAMS to rotate antennas.
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>  Well, if it's a little AC motor and a BIG HAM radio antena, then you
> already have a gear somewhere. Probably is an asynchrounous motor with
> a squirell type rotor and standard coil stator. Probably not. Better
> find out and tell us, don't let us scream here...
> :)
> cheers up,
> Vasile
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> 3/4 from my country is under the flood
> 1/1 from my politicians are corupted
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> >=20
> > Regards,
> >=20
> > Augusto =20
> >=20
> >=20
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