Variable Voltage (0-110 VAC)
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Greetings...
I'd like to control 8 pumps (110VAC). For this purpose, I'm using
Parallax Control Interface Board with Opto22 output modules. However,
I'd like to be able to vary the voltage to each pum, say, from 40 to
110 VAC.
One idea would be to use a servo to control the dial of a variac to
do this. Is there an easier way to do this?
Appreciate your time and response.
Said
I'd like to control 8 pumps (110VAC). For this purpose, I'm using
Parallax Control Interface Board with Opto22 output modules. However,
I'd like to be able to vary the voltage to each pum, say, from 40 to
110 VAC.
One idea would be to use a servo to control the dial of a variac to
do this. Is there an easier way to do this?
Appreciate your time and response.
Said
Comments
You would need to share more details about your pump motors. They may be
controllable via Thyristors. It would likely be simpler to control DC pump
motors...So what kind of motors are they, and what size???
Chris
> I'd like to control 8 pumps (110VAC). For this purpose, I'm using
> Parallax Control Interface Board with Opto22 output modules. However,
> I'd like to be able to vary the voltage to each pum, say, from 40 to
> 110 VAC.
>
> One idea would be to use a servo to control the dial of a variac to
> do this. Is there an easier way to do this?
>
> Appreciate your time and response.
>
> Said
>
AC motors work on a volts to hz ratio. you need to change the hertz
in relation to the voltage or else your motors will overheat and burn
up, quickly. Running a 110 motor on 100 volts during a brownout will
heat it up and it will either burn up or if you have a safety, shut
down.
The only way to decrease motor speed is to do what a variable speed
drive does, manipulate the volts and hertz. It actually runs the AC
motor on DC, but simulates the sine wave at like 16,000 hertz.
That is to say it switches the the beefy transistors on and off to
provide a pulse width to simulate the proper voltage.
not simple stuff and I do believe beyond the capability of the Stamp.
You would be much better using a DC motor if this is home brew stuff,
or a shaded pole motor that you can create a converter for. Like
they use for controlling power tools like wood routers.
http://www.4qdtec.com/pwm-01.html
is a simple explanation and some example circuits.
have fun !
btw, if you are trying to save energy $$ you can use a bypass control
on the pumps and use the stamp to allow a volume recirculate in the
pump itself, this would reduce the head and run less amps, not lots
less but less.
and valves are simpler for the Stamp to contorl.
--- In basicstamps@y..., "Chris Loiacono \(E-mail\)" <chris01@t...>
wrote:
> Said:
>
> You would need to share more details about your pump motors. They
may be
> controllable via Thyristors. It would likely be simpler to control
DC pump
> motors...So what kind of motors are they, and what size???
>
> Chris
>
> > I'd like to control 8 pumps (110VAC). For this purpose, I'm using
> > Parallax Control Interface Board with Opto22 output modules.
However,
> > I'd like to be able to vary the voltage to each pum, say, from 40
to
> > 110 VAC.
> >
> > One idea would be to use a servo to control the dial of a variac
to
> > do this. Is there an easier way to do this?
> >
> > Appreciate your time and response.
> >
> > Said
> >