I do not want to charge batteries

[Mark Cave]

I want to run my dc submersible pump with a small wind tubine. (NO batteries in between). I would love to grab somthing "off the shelf" that would do this, but when I call all these guys all they can tell me is how I have to charge batteries.
Batteries are great, but they are not for me. I just want to pump water. As much as possible. I will store the excess. Water is my battery.
I see batteries as an expensive "wear item" that will need to be replaced. I need 48 volts, so that gets pricey fast. I am looking for reliability at low dollars per watt. I have 6 wells using solar panels, but I want to do this one with wind.


Heres my problem: How do I regulate this thing so it won't burn up my pump. My pump can take about 300 watts max (anything from 36 to 96 volts).

I was thinking about getting one of those 48 volt PMA on a stick jobs like Hydrogen appliances, wind blue, survivalunlimited.

Then I could make a mount to let it furl. And/Or use a WINDYGIRL to shunt brake it at a certain voltage. (they will make one up to any voltage I request).

If I shunt brake this type of PMA will it slow down, will it fry?

PLease help. Hope I have not offened any Battery-o-philes.

[Rob Beckers]

Hi Mark,

Sounds like you already have a pump, if not take a look at Grundfos: They make a submersible pump that will run off just about any voltage in a wide range, meant for off-grid (their intention was directly off PV modules, but rectified wind power will do too).

As to PMAs: Some can be shorted (as the WindyGirl does) without damage, others will burn up quickly, or not be able to handle the rotor load and spin up again in higher winds (burning up the PMA in the process). So there's no saying if the PMA you're looking at will work or not, especially since that will also depend no the blades you bolt onto it.

In a larger context: Wind turbines need proper loading to work. Too little load and they'll run away, too much load and they'll stall. Load is variable, depending on wind speed. So, you would have to find a way to get the pump to properly load the turbine, not just to prevent overspeed, but also to just keep it running at the lower wind speeds. Eoltec worked with centrifugal pumps, driving them directly from a PMA and a wind turbine. Turns out that in such a scenario the load is just about ideal, following the cube of the wind speed. So, by coupling the right size centrifugal pump to their turbine they made it work for irrigation.

-RoB-

[Mark Cave]

I too like Grunfos SQflex pumps. They work great with solar panels no control box needed. But this other rebuilt pump is what I have on hand and the price is right (especially for this experimental installation).

Now about matching my load to my pma. Can't i just add a resistor, light bulb, heater, if need a little more load. How will I know I need more load?

I will probably end up with a bigger PMA than I need, because I need to pump a good amount of water at average wind speed (12mph). If I have to furl at 25mph that's OK.

[Stewart Corman]

Heres my problem: How do I regulate this thing so it won't burn up my pump. My pump can take about 300 watts max (anything from 36 to 96 volts).above line has some confusing numbers

If I understand your parameters:
wind turbine with 48v nominal output
you are running a DC pump motor
pump should go on at some minimum DC level
some high limit exists, whereby a dump load needs to kick in because excess voltage will overdrive the pumps wattage spec

in the attached photo I used a SS relay to trip a 115v coil/600v load power relay for DC loads to kick in at 10mph WS.
For you instead, using a standard relay with a 12v DC coil, then it will trip your pump on at 12volts
this allows wind turbine to be free load for easy starting
By using a resistor voltage divider, you can set a second 12v relay to click in a resistor dump load at say 48v
pump will still run at max operating voltage (wattage), but load down the turbine
if it attempts to drive above 48v ...but pump keeps running

did I miss something basic here??

Stew Corman from sunny Endicott
http://www.greenpowertalk.org/attachment.php?attachmentid=558&d=1226174829

http://www.greenpowertalk.org/attachment.php?attachmentid=557&d=1226174580

[Mark Cave]

That would work great. I wish I could buy that off the shelf somewhere. But how do I sense the voltages and make them my "trigger points" to kick my relays. I can't run a board, because I have no batteries.

[Stewart Corman]

Mark,
you are trying way toooo hard
if you look at the upper photo, you'll see a terminal block with two resistors.
They form a voltage divider ... the same current goes through both resistors
the voltage drop for each is therefore V=IxR

http://www.facstaff.bucknell.edu/mastascu/eLessonsHtml/Resist/Resist3A01.gif

example:
if you choose a 10K and 40K resistor in series = 50K, then any voltage applied across them both will have the voltage divided proportional to each resistor leg ...for 48v, then the voltage is divided into 48x10/50 leg and 48x40/50 ...so you will have 9.6v across one and 38.4v across the other ..this works well for tripping a SSR.

Only catch here is that the coil on a 12v relay has finite resistance, such as the 12v one in my hand is 122 ohms and that will be parallel to Rb in diagram. So, you can replace the Rb with the relay coil instead. But 10K + 122 = 10,122 ohms and the divider is now 100:1 ...choose a smaller resistor for Ra, but watch how much current is being drawn.. you don't want the resistor glowing red :blink1:
P=V**2/R so 48x48/500ohms = 4.6 watts (this requires a power rated resistor)

you'll have to experiment to see what size resistor trips the relay at desired voltage

Hope this helps

Stew

[Mark Cave]

Thanks Stew, that's not quite as hard as I thought, I may try that route later if my current plan doesn't work. I passed circuits, but not by much. What kind of relay is that you are using?

My current plan. I am building a windmill with a Delco PMA rewound for higher voltage. I am going to wire it strait to the pump. I am not worried about the low voltage (cut in) This pump ran for years on a solar panel with no controller and voltages too low to turn the motor had no ill effects. I looked at the motor when I rebuilt it. I am going to wire an amp and volt meter into a box so I can monitor it.

I am going to build a furling mechanism to turn the blades out of the wind at about 30mph, or before I cook my pump motor.

[Mark Cave]

I installed the unit yesterday. Today we had some high wind (44 mph gusts) so I was able to evaluate my design.

I have a Delco PMA with 6 (Hydrogen Appliances) blades and a furling tail mechanism on top. I rectified it to dc in my control box. Control box is pretty simple. Fuse, switch, volt, and amp meter. Then it goes 120 foot down hole to a AllPower DC submersible pump.

Here's what happened. (wind speeds are approximate) It started at 18-20 mph and pumped water and at about 35-38 mph started to furl.

I am really happy and probably lucky on how the furling turned out. I don't think I'll change a thing except for adjusting my stop to allow it to furl a little farther.

I am not happy with how much wind it took to get my PMA started. 6 blades are supposed to start in low wind. Ha!

When I disconnected the PMA it would start at about 12 mph.

I am thinking about adding a capacitor to cushion the braking effect on the PMA. Does anyone think this will work? Suggestions Please. I have got to pump water at a lower wind speed.

[Dan Lenox]

Mark,

The newest release of my PowerDashboard software (http://www.briery.com) includes the ability to set 'triggers' for performing what is commonly referred to as auxiliary device control or commonly abbreviated as 'Aux Control'.

Like Stew, my software utilizes an off-the-shelf DataQ to perform digital switching. Most of these units typically have 6 digital outputs, meaning that up to 6 separate external devices can be controlled.

The digital outputs of the DataQ are typically not 'beefy' enough to directly control devices so the use of either a low cost electronic relay or solid state switch is required to handle the device(s).

The parameters for the user defined triggers include:

wind speed
turbine rpm
turbine voltage
turbine amps
turbine watts
drop or regain grid
battery voltage
battery amps
battery watts
battery voltage above/below float
battery voltage above/below absorb
battery state of charge
time of day


Any trigger definition can include one or any combination of parameters, and can switch a digital output either On or Off, and multiple triggers can be defined in the system.

In your case my software can monitor turbine rpm and when the speed is below a preset value it can switch out the pump, and when the speed increases above another point it can switch the pump on. Another set point can be defined to potentially 'kick in' additional load(s) if your turbine output gets too high!

There are *tons* of uses for digital switching! But until now it seemed like auxiliary device control has not been able to be done consistantly.

This version of the software will be officially released in about 2 weeks, right now it is being beta tested by a number of users, and also includes interfacing to the current Outback product line.

Dan Lenox

[Stewart Corman]

Mark,

I am not happy with how much wind it took to get my PMA started. 6 blades are supposed to start in low wind. Ha!

won't start at all if you apply a big enough brake!

I agree with Dan ...the most important control you need is to switch out the pump when the blades aren't producing enough power.

Let it come up to speed where you get some aerodynamic effects, then apply the pump load. It appears that you are overloading the turbine blades, which could explain why you get such poor low wind performance . More blades should be better for you, but they still have to spin fast enough to deliver power. If you apply the pump full bore, then you effectively are braking the rotor. The generator has to be matched to the rpm vs load.

Best implementation is to gradually apply the load, but that requires a PWM controller ...these have been discussed on Otherpower and I am formulating a design for my unit.
Basic implementation is based on a PWM chip TL4994CN driving a hivoltage/hicurrent darlington pair.


Currently I have four different fixed loads to attempt to see how each functions over different wind speeds vs no load. The PWM basically fakes a variable load by juggling the voltage output not unlike a motor speed control. The crude way for me is to use a SSR to pick off each of four loads in succession ...you only have a single load ie the coil of the pump, so you have to do it more sophisticated.

Stew Corman from sunny Endicott