Hydro load controller to keep generator rpm's on target.

[John II]

Using a 3 kw 110v ac single phase generator, I need a simple circuit that would add a dump load to my generator to keep it from over speeding when it's other loads are light.

I need it to detect over voltage and slowly increase the dump load ( such as resistant heaters) to maintain a constant 110 volts and constant generator rpms.

I have read about circuits using scrs to do this. I searched the board for this, and didn't turn up anything... maybe I didn't use the right search parameters.

Does anyone have any info on this ?

John II

[veewee77]

I would think, and this will only apply if the generator is hydrocarbon powered, that if you load the generator with something other than a useful load, you will be wasting fuel.  It requires more fule to run a loaded generator than it does an unloaded one.

It would be better to govern the generator somehow instead of loading to maintain RPM.

If it is wind or water powered, that is a different story, though.

DS

[John II]

It's water powered.

John II

[wpowokal]

John,

     Have a look at these HomePower articals

http://www.homepower.com/files/homebrewhydro.pdf

http://www.homepower.com/files/shuntregulationhp72.pdf

http://www.homepower.com/files/shuntregulator18.pdf

They may help, for my money a simple shunt regulator dumping to a heating element is the simple way, could be to water heating space heating of just to the greate outdoors.

regards Allan    

[Vtbsr]

Would going with a DC generator be a lot simpler? It seems like every time you turn on a light you will have to increase flow to the generator and your volts will vary with ac system. With DC you can charge a large battery bank at a set output. When you have large loads or motors starting the inverter will take care of it. The battery bank is like the grid which tends to stablize the system. What do you have for a turbine, distance to house, head, ect.? Might be able to give more ideas if I know more about site.

[John II]

Thanks everyone for your input. I think I found a circuit that will do the job from an extensive google search.

Thanks again for your efforts,

John II

[domwild]

John,

Look at Hugh Piggott's site (scoraigwind, I believe) for his load controller. After the transformer the low voltage AC is driving a LM2917 frequency to voltage controller which then drives  one or more triacs to switch the AC load(s) on or off before the rectifiers. How you are going to generate 50 or 60HZ 240VAC from varying AC voltages I do not know.

Dominic

[John II]

Truth be told !!!

Ok Guys, it's time for me to come on the level with you. I stated that the circuit I needed was for "hydro" so you would spend time helping me find the circuit I was looking for, instead of jumping all over me for being slightly crazy ! haha

Here's my actual application. We currently have a 2000 watt pv array that puts out about 17 amps at 120vdc. Open voltage it runs all the way up to about 203 volts dc.

While I'm hoping to eventually build a homemade inverter, I can not afford to purchase a commercial one, as they start out at over $6K

It occured to me, that I could at least demonstrate the PV's power output to friends and neighbors and get some limited use out of it, if I pulley drove a ac alternator with a 3hp 180vdc motor. I have played with this arrangement under controlled loads, but if the load were to be removed the system would over speed, I'd have ultra high voltages and probably throw the windings off of my alternator armature!

So while it's both impractical, and very energy wasting, If I were to put a dump load on the alternator to maintain it's voltage into a "safe level" I could get limited usage out of it (without the need for an electronic inverter) or even batteries. Friends and neighbors could also witness what PV's alone can do.

A better setup would be to drive an igbt brick with pwm to control the dc input to my 3hp drive motor. The pwm would be controlled by the alternator's frequency output. This would conserve energy and allow the unit to also run from a 120vdc battery bank at a later date.

Of course an 120vdc Electronic inverter is the ultimate goal. But hey 120vdc at 17 amps going to waste every day is more than I can take !

Yes Dominic, That's the circuit I think Ill try to modify for my own usage unless I can come up with something better suited. And I love your tag line ! I think that just about describes a lot of us. Haha

veewee77, Allan and Vtbsr, Thanks for your concern and desire to help also.

It shouldn't be so hard one would think. Just a glorified lamp dimmer with external feed back of some sort.

Now if I could just find something to plug my electric drill into !

John II

[TomW]

John;

Hmm, glad you decided to be straight about your application. However, I think misrepresenting what you are doing was pretty sneaky and less than helpful to your cause. Personally, once someone shovels bull waste on me I can no longer trust them. This leads to all kinds of problems later when that person gives information or advice.

You should have just been up front about what you were doing rather than use subterfuge [something intended to misrepresent the true nature of an activity] to get help.

Just my opinion.

T

[John II]

Possibly true TomW, I'd probably gotten all kinds of responses (why would you wanta do something like that) the other way. It's hard to please all. It should have been stated "needed a hydro dump controller" That's what I'm looking for in my particular application. Looks like it ought to be something simple to find doesn't it ? I still haven't found a circuit made for that particular application outside of the Austraulian cpu unit which does not detail schematics or firmware.

John II

[Nando]

John II:

I hope I am not posting twice I can not find the first

Please connect directly with me I have one controller that is simple and quite good, I would like to discuss with you.

Regards

Nando

nando37 at comcast dot net