I think this defies the principles of electricity but here goes...

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  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: I think this defies the principles of electricity but here goes...
    bar001 wrote: »
    I do have a charge controller which had 3 input points, a 32v fuse and 2 output points. Would that suffice? If so, how do i connect all the components up?

    One thing you don't want to do is try to fit a charge controller in here. You're looking to find the maximum power output. The controller will try to regulate output, and expects to find batteries on its output.

    Otherwise you need six rectifiers (diodes) capable of handling 30+ Amps of current. Most of the ones you'll find aren't up to it; they're usually about 1 Amp. You could possibly pull some from (for) a car alternator. They would be connected as per the diagram in my previous post.

    You can also test the actual output type of the turbine with a digital multimeter and a couple of "alligator clips". Attach the leads to one "set" of wires at a time with the meter set on DC Volts and give the turbine a gentle spin. You may see fluctuating between positive and negative Volts or a meager steady output. Switch to AC Volts and spin it again. If it reads higher the output is AC; lower and it's DC (hard to describe this test with words - sorry).
    I am also confused when it comes to the volt and amp meter. as i described, it has the 4 wires and the shunt. I am still confused, even after reading the instructions as to how to safely wire it up. What do i do with the ground wire?

    Unfortunately I don't have the instructions. Normally I'd expect one wire for positive, another for negative (on one side of the shunt), a third wire to the other side of the shunt (Voltage difference across the shunt is how it calculates current), and the fourth to be the electrical safety ground. This last one is not essential for operation but is used for permanent installations.

    But this may not be the case. You have to study the instructions.
  • bar001bar001 Registered Users Posts: 15
    Re: I think this defies the principles of electricity but here goes...

    I really appreciate all your time and effor in answering my questions. It has greatly contributed to my understanding however, I am still completely out of my depth. I am not electrically trained and this is all too complicated for me. I am going to try find an electrician who is capable of setting this up for me as I'm worried that I'm going to go off only haf understanding what I need to do.

    When I undertook the experiment, I could never have fathomed that it would be so complicated to take a turbine in a 30mph wind and see how many watts it would REALLY produce. Its crazy. I guess the fact that o cammot connect directly to the grid (even thoug I want AC results as though it were connected to the grid) make is a bit more complex but still, I'm completely blown away.
  • BB.BB. Super Moderators, Administrators Posts: 30,629 admin
    Re: I think this defies the principles of electricity but here goes...

    The voltage/current meter four wires are probably +/- to measure voltage, and another pair (again +/-) to connect to the two small screws on the side of the shunt. The large terminals on the shunt would be inserted into the (typically) negative side of the current wiring where you want to measure the amperage.

    Regarding a load bank--A "cheap" way of doing this--Get some used batteries and make a 24 volt battery bank (or even used forklift batteries). They will usually keep the voltage somewhere in the 24-29 volt range even if they are not very good batteries. And over 29 volts, they will start electrolysis (generating hydrogen/oxygen gasses). Not great to do that a lot to batteries--but as long as the batteries are well vented, don't get too hot, and have the plates covered with electrolyte--it will work... And you can switch in your dummy load if needed.

    Remember, dealing with batteries, wind turbines, etc. can be quite dangerous. From gas explosions, meltdowns, acid leaks, and blades/hubs self destructing/alternators overheating/seizing, etc... You have to very careful to protect yourself.

    If you are doing field testing, you need some way of shutting down the turbine in high winds. Mechanical brakes, furling from wind, feathering props, etc. ... At least one alternative to shutdown a turbine besides the standard throw a shunt across the two (DC) or three (AC) output wiring.

    It is not unusual for a shorted alternator to have so much torque from a wind storm against the prop that it can overheat the alternator and/or over-speed to self destruction... So having a second (or even third) method to shut down is usually a very good idea.

    And this is why placing a breaker (or on/off switch) in series between the alternator and the battery bank is not a good idea. If the breaker/switch opens, the turbine will likely over speed in even moderate winds.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: I think this defies the principles of electricity but here goes...

    Fortunately, Bill, the plan here is to test the unit on the ground under controlled conditions. That's why we've left out the batteries and put in the fuse to protect the fixed load. Originally the plan was to test several different turbines, but because they are different it really throws a wrench in the works for setting fixed test parameters.

    Ah, the joy of photovoltaics! Compared to wind they're dead simple! :D
  • bar001bar001 Registered Users Posts: 15
    Re: I think this defies the principles of electricity but here goes...

    I have purchased a 3-phase rectifier bridge capable of handling the maximum output of the unit.

    While i'm still completely lost, I am determined to get to the end point of this experiment. What is the order for connecting the system up? It was simple when i had less parts! If I have the order right, I should be able to figure out the wiring.

    bar001
  • stephendvstephendv Solar Expert Posts: 1,571 ✭✭
    Re: I think this defies the principles of electricity but here goes...
    bar001 wrote: »
    When I undertook the experiment, I could never have fathomed that it would be so complicated to take a turbine in a 30mph wind and see how many watts it would REALLY produce. Its crazy. I guess the fact that o cammot connect directly to the grid (even thoug I want AC results as though it were connected to the grid) make is a bit more complex but still, I'm completely blown away.

    The word "REALLY" there is a bit tricky because it will also depend on the load. Usually the turbine manufacturers of grid tied units provide a Maximum Power Point graph with the turbine. This tells you the optimum Amps to get a specific voltage. The same wind on the same turbine, with a different load will produce a different amount of "REAL" power.

    So to do your experiment, I'd connect the outputs of the turbine to the bridge rectifier, then the rectifier + to a variable resistor (or a bank of fixed resistors) and the other side of the resistors back to the negative of the rectifier.
    Then with a given turbine and a given wind speed, note the V and the A in the circuit. Then reduce the resistance and measure the V and A again and repeat for a few different resistance values.
  • PolaracoPolaraco Solar Expert Posts: 102 ✭✭✭✭
    Re: I think this defies the principles of electricity but here goes...

    Turbines Ugh

    Based on what I am reading, you got a used Missouri Wind and solar unit. You'll be lucky if you see 90 watts.

    Typically they use a slip ring on those. So you need the correct mount. It's been proven 3 phase A/C isn't any more efficient than a DC unit. Just FYI. Best and most typical for a 3 phase small turbine, is #10 wire from the slip ring. Missouri is using a trailer connector whose wire is too light. But in their case, #16 is sufficient.

    For everyone's Info. These are NOT car alternators. The GM housing is used because of cost. There are so many out there. The brush less permanent Magnet units. There is no powering of the field. That is a misconception by so many people. They vary in output. Missouri advertises 1600 watts at any voltage. HAH! But if you get 90 watts at 24VDC. consider yourself lucky. Check out YouTube.

    I have 4 of these turbines running. They do work, but you need the right blades for your wind.

    You'll have to excuse me, I recently had a stroke, maybe 2 and seems to be unable to absorb info. I'll catch up. I know allot about these mini turbines. They do work set up right.
  • PolaracoPolaraco Solar Expert Posts: 102 ✭✭✭✭
    Re: I think this defies the principles of electricity but here goes...

    Re reading I think I know what you are trying to do.

    The batteries act as a voltage regulator. And you will probably need some sort of a dump load. Some generators put out more than others. Inverters are typically reliant on those batteries to maintain a constant voltage. A DC Generator is almost AC actually, so the bats even that out. I have watched my meters on my solar/wind setup and watch the amp meters jumping all over on the line side, but pretty flat on the load side.

    If this is just a test bench, why not just power the generator with a motor. I doubt a squirl cage will make enough wind for this. Tune the motor to turn the turbine between 1200 and 1500 RPM.

    Yeah I did skip posts, so if this is redundant. . .
  • BB.BB. Super Moderators, Administrators Posts: 30,629 admin
    Re: I think this defies the principles of electricity but here goes...

    Unless you are doing scale models (and there is all sorts of math when doing "real" scale modeling), mounting on the front of a truck with a mile or two of straight/quiet road, or field testing--Very few people will have a large enough, and powerful enough, wind tunnel to do a full scale test of a wind turbine (think of a 750 Watt Wind Turbine needing on the order of 10 HP/7,500 watts of motor power driving the wind tunnel for "nominal" measurements).

    I will agree with Polaraco and repeat my suggestion... Break the project into two parts. One with some sort of variable speed motor drive (electronic, belts, etc.) that is at least 2x the wattage of the alternator that you want to test and direct drive the alternator (and add your loads/load bank/battery bank as needed to take your data).

    Plot this data on Linear, Semi-Log, and Log/Log graph paper (or display with a spread sheet program) the three chart types. Very often a strange curve of power vs current vs voltage vs rpm will turn into a straight line (or close enough) with semi log or log/log graphing (allows you to better predict output).

    Then look into the design of your blades and how they will perform (wind speed vs RPM/Torque). You should be able to overlay your blade performance onto your alternator loading graph.

    But read up on the www.otherpower.com and their discussion forum... Understand their design rules of thumb and what they are doing. Should give a lot of insight into the variable behind wind turbine design and testing.

    This is a very complex subject and not easy to hit the ground running (however, it is it easy to hit the ground :p).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PolaracoPolaraco Solar Expert Posts: 102 ✭✭✭✭
    Re: I think this defies the principles of electricity but here goes...

    Wind is tough to do unless you live on a ocean coast, or high altitude in the open. The first thing you need to do is study the wind and direction available to you. It's more complicated from that point. For some, but I have it down pat now.

    I decided to go with a bunch of smaller units because they cost less, and easier to install. Also, I get more from 4 smaller units spinning. The potential of small units getting to speed is pretty good to bigger units too.


    Just sayin
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