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help with windgenerator - long — Parallax Forums

help with windgenerator - long

ArchiverArchiver Posts: 46,084
edited 2003-11-12 10:59 in General Discussion
Hi Melvin,

as Steve posted, (thanks Steve) a 10ga solid wire has a resistance
of 0.001 ohms per foot. A Shunt is a length of know resistance wire
capable of carrying the entire load with little effect on the load.

I'm not sure of the wire gauge you plan on using, but you can take a
one foot, or 20 foot length and connect a wire to each end. this
means you can use the existing wire from the generator to the battery
and use that to measure current. This signal wire will not be load
related so it can be thin.

you can bring this into an op-amp and use the op-amp to generate a 0
to 5 volt output that would be equal to zero amps and the 5 volt
would be equal to about 10-20% greater than the max amps you expect.

so the existing wire can be used to calculate the amps generated.

use a Analogue to Digital converter, the LT1298 is covered in the
Parallax literature so you don't have to create something new.

The 5 volts is seen by the LT1298 and that converts the voltage so
the Stamp can read the current.

so far you are really just assembling the parts.

The LT1298 has two inputs and the second would have to be for
voltage. in this case, a voltage divider so your maximum expected
voltage is about 80% of the range. simple resistors, simple math.
simple google search.

The Stamp would then look at the voltage and as the voltage increased
to some level you pick in software, the Stamp would signal a relay to
some device. as you mentioned, you wanted to use a heater.

And you have to start with voltages as unless you put a load across
the generator, you cannot get a current flow, so measuring current
will not allow you to control the very first thing. Controlling by
voltage is the way to start.

There are some extremely cheap heaters, just a couple bux each,
available in wattage's from about 1 watt to well over 1,000 watts.
the neat thing is they have an integral visual indicator as to
voltage. The problem is that they max out at about 100 volts.
google incandescent light bulbs. yup, simple lightbulbs are great
heaters. and you can run them on very wide range of voltages. A
note is that at low volts, it will act like a resistive heater and
then as the voltage increases, the element will start to glow. As
the voltage increases over some level it will glow brighter.

you can monitor voltage and as it increases, power more devices so
the current increases and the voltage drops.

With 3 outputs, and 100, 200 and 400 watt loads, you can control
1000,200,300,400,500,600 and 700 watts of output. Add a 4th output
and you can you can get 100 thru 1,500 watts in 100 watt steps. Or
any ranges you want to use.

A board of education and a few additional parts and you have all the
hardware. then programming should be pretty simple.


Dave








--- In basicstamps@yahoogroups.com, "Hall, Melvin GR" <HallMG@b...>
wrote:
> The generator is currently under constuction so all my numbers are
theoretical but I will thoroughly test the alternator before putting
it to use. The alternator has ten coils which are arranged in pairs
to give a five phase output. This is rectified at the top of the
windmill tower to give a course dc which is carried down the pole to
the ground using a pos and neg cable.
> At maximum continuous running speed the voltage is likely to be
around 70v, current of around 10A
> and so power of around 700w. I am not sure what you mean by the
terms 555, bs2, adc and shunt, please could you tell me more about
them. If the controller you suggest can switch on relays at various
voltage thresholds then the best idea may be to use several small
elements, say 100w each and have them switching on one at a time.
>
> Melvin
>
>
Original Message
> From: Dave Mucha [noparse][[/noparse]mailto:davemucha@j...]
> Sent: 11 November 2003 01:28
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] Re: help with a controller for a
windgenerator
> powered heater
>
>
> --- In basicstamps@yahoogroups.com, "Hall, Melvin GR" <HallMG@b...>
> wrote:
> > I will need some kind of controller that will only connect the
load
> to the generator when it gets up to speed so it wont stall.
> >
> > Melvin.
>
>
> There are more than a few ways to make a cheap ADC.
>
> a 555 and a BS2 can work together as a cheap ADC.
>
> I have not tried an RC to see how it would work as the voltage
> changes, but there is no reason why you can't make some very simple
> and low cost voltage monitoring and then as you pass each
threshold,
> you can open or close different relays.
>
> if you get a milti channel ADC, you can also put in a shunt and
> measure the current the unit is putting out and control your load
> that way too. the wire itself can be used. I'm not sure of your
> amps, but a few feet of wire has a measurable resistance and would
> change as the voltage changes yielding an amp reading.
>
> There was a link to resistance per foot, I am guessing someone on
> here posted a link some time ago. ?
>
>
> do you have a link to the generator ?
>
> It would help if we had some of the parts to he puzzle.
>
> Dave
>
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
Subject and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-11-12 10:59
    I am still not sure what you mean about the shunt, is this length of wire
    connected is series or parrallel with the output cable? Do I need a seperate
    power supply for the control unit? If you could provide a diagram of how to
    connect the parts up I would be very grateful.

    Original Message
    From: Dave Mucha [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=AhMEnJkTIajjvm-xVd4-0yX1xR26VwKbrgadnI3eYe79IJexmBo_srh0ooc4vgdd7GaN4PBKXMj8EhY]davemucha@j...[/url
    Sent: 11 November 2003 23:18
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Re: help with windgenerator - long


    Hi Melvin,

    as Steve posted, (thanks Steve) a 10ga solid wire has a resistance
    of 0.001 ohms per foot. A Shunt is a length of know resistance wire
    capable of carrying the entire load with little effect on the load.

    I'm not sure of the wire gauge you plan on using, but you can take a
    one foot, or 20 foot length and connect a wire to each end. this
    means you can use the existing wire from the generator to the battery
    and use that to measure current. This signal wire will not be load
    related so it can be thin.

    you can bring this into an op-amp and use the op-amp to generate a 0
    to 5 volt output that would be equal to zero amps and the 5 volt
    would be equal to about 10-20% greater than the max amps you expect.

    so the existing wire can be used to calculate the amps generated.

    use a Analogue to Digital converter, the LT1298 is covered in the
    Parallax literature so you don't have to create something new.

    The 5 volts is seen by the LT1298 and that converts the voltage so
    the Stamp can read the current.

    so far you are really just assembling the parts.

    The LT1298 has two inputs and the second would have to be for
    voltage. in this case, a voltage divider so your maximum expected
    voltage is about 80% of the range. simple resistors, simple math.
    simple google search.

    The Stamp would then look at the voltage and as the voltage increased
    to some level you pick in software, the Stamp would signal a relay to
    some device. as you mentioned, you wanted to use a heater.

    And you have to start with voltages as unless you put a load across
    the generator, you cannot get a current flow, so measuring current
    will not allow you to control the very first thing. Controlling by
    voltage is the way to start.

    There are some extremely cheap heaters, just a couple bux each,
    available in wattage's from about 1 watt to well over 1,000 watts.
    the neat thing is they have an integral visual indicator as to
    voltage. The problem is that they max out at about 100 volts.
    google incandescent light bulbs. yup, simple lightbulbs are great
    heaters. and you can run them on very wide range of voltages. A
    note is that at low volts, it will act like a resistive heater and
    then as the voltage increases, the element will start to glow. As
    the voltage increases over some level it will glow brighter.

    you can monitor voltage and as it increases, power more devices so
    the current increases and the voltage drops.

    With 3 outputs, and 100, 200 and 400 watt loads, you can control
    1000,200,300,400,500,600 and 700 watts of output. Add a 4th output
    and you can you can get 100 thru 1,500 watts in 100 watt steps. Or
    any ranges you want to use.

    A board of education and a few additional parts and you have all the
    hardware. then programming should be pretty simple.


    Dave








    --- In basicstamps@yahoogroups.com, "Hall, Melvin GR" <HallMG@b...>
    wrote:
    > The generator is currently under constuction so all my numbers are
    theoretical but I will thoroughly test the alternator before putting
    it to use. The alternator has ten coils which are arranged in pairs
    to give a five phase output. This is rectified at the top of the
    windmill tower to give a course dc which is carried down the pole to
    the ground using a pos and neg cable.
    > At maximum continuous running speed the voltage is likely to be
    around 70v, current of around 10A
    > and so power of around 700w. I am not sure what you mean by the
    terms 555, bs2, adc and shunt, please could you tell me more about
    them. If the controller you suggest can switch on relays at various
    voltage thresholds then the best idea may be to use several small
    elements, say 100w each and have them switching on one at a time.
    >
    > Melvin
    >
    >
    Original Message
    > From: Dave Mucha [noparse][[/noparse]mailto:davemucha@j...]
    > Sent: 11 November 2003 01:28
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] Re: help with a controller for a
    windgenerator
    > powered heater
    >
    >
    > --- In basicstamps@yahoogroups.com, "Hall, Melvin GR" <HallMG@b...>
    > wrote:
    > > I will need some kind of controller that will only connect the
    load
    > to the generator when it gets up to speed so it wont stall.
    > >
    > > Melvin.
    >
    >
    > There are more than a few ways to make a cheap ADC.
    >
    > a 555 and a BS2 can work together as a cheap ADC.
    >
    > I have not tried an RC to see how it would work as the voltage
    > changes, but there is no reason why you can't make some very simple
    > and low cost voltage monitoring and then as you pass each
    threshold,
    > you can open or close different relays.
    >
    > if you get a milti channel ADC, you can also put in a shunt and
    > measure the current the unit is putting out and control your load
    > that way too. the wire itself can be used. I'm not sure of your
    > amps, but a few feet of wire has a measurable resistance and would
    > change as the voltage changes yielding an amp reading.
    >
    > There was a link to resistance per foot, I am guessing someone on
    > here posted a link some time ago. ?
    >
    >
    > do you have a link to the generator ?
    >
    > It would help if we had some of the parts to he puzzle.
    >
    > Dave
    >
    >
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the
    Subject and Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to
    http://docs.yahoo.com/info/terms/


    To UNSUBSCRIBE, just send mail to:
    basicstamps-unsubscribe@yahoogroups.com
    from the same email address that you subscribed. Text in the Subject and Body
    of the message will be ignored.


    Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
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