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Forum Index : Electronics : Question : Rpm-Amps :Comanda / Everyone

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fillm

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Joined: 10/02/2007
Location: Australia
Posts: 730
Posted: 11:41am 18 Nov 2007
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Hi,
I have been reading your posts with intrest , you posted a repily about a star /delta controller in windmills with an amp meter , volt meter built in to the circuit . I am currently building a second mill identicial to the one pictured in my posts , what I would like to have is a monitoring system , mainly wind speed / rotor rpm to be able to monitor improvements to blade design/angle , have thought using the ac frequency to get rpms as i think eccoinovation use for their series / paralell switch . Being fairly electronicly challanged its a mind boggleing project to get into but I can see the benifits rather than look up at the mill and guess rpms then look at the amps , anyway if you have any ideas on how to set this up it would be appreciated or if there is anthing on the market that can monitor and log windgen performance or anyone out there might know where to get such an instrument I would love to know where to get it or how to make it for the electronically challanged person ?...Regards..Phill....
PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits
 
Highlander

Senior Member

Joined: 03/10/2006
Location: Australia
Posts: 266
Posted: 08:07am 19 Nov 2007
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Sounds like you need to build Glenn's logger. But if your not inclined to do so perhaps you could bribe one of the guys to build you one.
Also if you want RPM you appear to have the unrectified ac coming down the mast so this may be of some use to you.
I never looked into the rs logging features, perhaps it might be what you want.
Central Victorian highlands
 
GWatPE

Senior Member

Joined: 01/09/2006
Location: Australia
Posts: 2127
Posted: 10:00pm 19 Nov 2007
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Hi phil,

The main problem you have with logging and wind is the recording data rate. To get meaningful comparison data you need a fast recording. approx 2-3 samples per second at least.

I use a logger [a digital power recorder, DPR-50] for spot checking and recording. up to 10 recordings per second for volts and amps. This is a break and insert type recorder designed for the model plane industry. Works well at 12 or 24V levels.

I am looking at an building an opto coupled 12 channel display/logger.

cheers, Gordon.
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fillm

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Joined: 10/02/2007
Location: Australia
Posts: 730
Posted: 10:09pm 19 Nov 2007
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Thanks Gordon / Vic
can the opto coupled 12 channel display logger record rpms as well as amps/ volts , and what do they cost ? ..
PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits
 
commanda
Newbie

Joined: 12/11/2007
Location: Australia
Posts: 14
Posted: 06:21am 20 Nov 2007
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I made a "combined metering board". Tacho, star-delta switch, ammeter, expanded scale voltmeter. The individual circuits are in a zip file I uploaded here. Display is via 3 seperate analog meter movements. Board was professionally made by RCS radio. I sold a few complete units on ebay for about $100-120. Can be 12 or 24 volt system. You need access to the ac before the rectifiers for the tacho, so if the rectifiers are in the battery room that is good. Still have a number of the boards. No logging though.

Amanda
 
fillm

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Joined: 10/02/2007
Location: Australia
Posts: 730
Posted: 07:51am 20 Nov 2007
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Hi Amanda,
Thanks for your repily , seems like you are pretty switched on with all the electronic gear, yes I am interested in one of these if you have one for sale , I have ac down to the base of the mast where i switch the star / delta relays the controll box is only 12mt away but I am running at 48 to 60 volts because of going into the grid through a latronics PVE 1200 invertor eventually. Can the metering board be stepped down or another opt could be to tap 24v of the battery bank..Is there anyway of incorperating a annemometer into the read out and do the meters have to be annalogue ? Can pay or put together a dual stator set up for you.Whatever ...Thanks ..Phill..Edited by fillm 2007-11-22
PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits
 
GWatPE

Senior Member

Joined: 01/09/2006
Location: Australia
Posts: 2127
Posted: 11:37pm 20 Nov 2007
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Hi Phil,

The reason for opto coupling is, most DIY, backsheders, make additions to their system when time or dollars permit. We make changes and additions. Not all of us have perfectly designed switchboards, wiring etc. It is fine to have separate stand alone circuits for each function we wish to look at. When we wish to record with a logger etc, we encounter problems bringing all of the signals to a common reference earth for the datalogging A/D converter.

Ground loops that have current flowing can introduce huge measurement errors. Sometimes there is no DC path for measurement signals.

I am developing a system that allows each of the individual, or groups of common ground analogue signals to be converted to data, and then opto coupled to a single micro that communicates to a PC, logger or display device.

No, the prototype is not made yet. I am intending to add this functionality to all of my mill and solar ccts so I can measure and record pretty much every variable using the same type of component. All of the calibration is done within the micro code.

I hope to provide some status reports on the PWM-picaxe-08 thread.

cheers, Gordon.




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commanda
Newbie

Joined: 12/11/2007
Location: Australia
Posts: 14
Posted: 07:05am 21 Nov 2007
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Phil,

It sounds to me like what I have is not what you really want. I never considered adding an extra tacho channel for an anemometer. And yes the meters have to be analog. The circuitry was designed that way. Running digital panel meters each with their own seperate battery is all well and good, but powering them off the main battery bank just gets too hard.

And using analog meters uses a different part of the brain than looking at digital meters. With an analog meter, you can tell at a glance whether the battery voltage is high or low, are we making lots of rpm, are we making lots of current. This is what you need to know. With a digital meter, you need to interpret the numbers more.

Well actually, the meters don't really have to be analog. It could be made to work with digital meters each powered off its own 9 volt battery.

And I've never actually gotten around to setting one up for 48 volts. Easy enough to do if you power the board off the single most negative battery (12 volts) and pull the battery voltage sense out as a seperate wire.

Amanda
 
commanda
Newbie

Joined: 12/11/2007
Location: Australia
Posts: 14
Posted: 07:26am 21 Nov 2007
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Phil,

Thinking about it some more, if you go with digital meters the on-board voltmeter circuitry becomes redundant. It's designed to be expanded scale, like 20-30 volts for a 24 volt system. Only makes sense with an analog meter.

Amanda
 
GWatPE

Senior Member

Joined: 01/09/2006
Location: Australia
Posts: 2127
Posted: 01:14pm 21 Nov 2007
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Hi Phil,

Please do not tap current off the bottom battery. This will in a short while cause an imbalance in your battery bank. A metering current of say 20mA will lower the battery it is connected to by 1Ah every 2 days.

It is better to run any meter cct from the main rail using dropping resistor or better a DC-DC converter. I normally use a constant current source instead of a resistor if I don't use a DC-DC converter.

The only meter I have with a battery is a multimeter, used for spot measurement checking, etc.

I have a cct that uses a large 20mm digit, 5V common earth LED display. The display is manually switched between amps or volts. The 3.5 digit display runs OFF a DC-DC converter on the 24V battery, consuming only about 12mA instead of the normal 60-70mA if using a 7805 regulator. The cct connects across the shunt in the negative and has a fly lead to battery positive. Will read 0-30A in 100mA steps and 18-30V in 100mV steps.

I have the readout on the wall in the house so I always know the status of the battery.

I have a SunnyBoy grid connect inverter that I feed excess power back to the grid. Is the Latronics a PV edge type. I was going to get one of these but they only had some LED indicators and I wanted full kWhr metering. I believe these inverters also draw down the battery when gridfeeding. My gridfeed cct maintains the battery at the float voltage, and does not discharge the battery. I have to DC-DC convert up to 150V from the 24V battery. I only sell surplus power.

let us know how you get on when all is in operation.

cheers, Gordon.


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fillm

Guru

Joined: 10/02/2007
Location: Australia
Posts: 730
Posted: 11:32am 22 Nov 2007
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Hi Gordon & Amanda ,
Hav'nt been near a computer for a while , change from day to night shift. I'll explain the reason for going with the PVE edge 1200 , it has a mppt disconect switch and when enabled the set point starts feeding into the grid is set at 54v so as battery voltage increases above it starts feed and tracking at 10w up to 1200 to 1300w @ 100v cut out so the batts never go below 54v which I figure is pretty well full charge . I realise it only has a set of leds to indicate grid feed , I have the windmill going in to the batts via a PL20 which loggs total amps for a 24 hr period and will store 30 days info which should give me a fair indication of how many watt/hrs have been made . And if the grid is down and the mills are making heaps then the power is lost to a dump load at 62v. I do nt need a big expensive batt bank , although as you can see in the pics I am using wet cell nickel cads but they were found at the dump , 4 x 50 amp car batts would do as they are only there to giv a smooth dc line for the inverter.. That is also the reason why I have been only going with 48v for my mill output volts as all the other inverters are at 110v and I then dont have to use a dc/dc converter so no losses , the Pve 1200 is at present the only one that runs at 54v and can be parralelled although I must add that I do not have it set up into the grid as yet , I am waiting for the approval on the $8000 grant and it will all be installed together with a 1 kw PV system and 2 X PVE 1200 inverters , one for the solar and one for the wind gens and extra panels as I add . But at present with the what I've seen coming out of one dual neo with two flying in 5 to 7 m/s I should almost be at full capacity on one inverter and having the batts volts increasing as the inverter is at full feed and as the wind drops the inverter pulls the excess of and and returns the batts to 54v.. I should prabably now get back to the origional topic of wind speed / blade RPMs which I am having a bit of trouble getting my head arround as it's not my field of good knowledge or expertice but I can see the benifits with improving blade performance which with the standard rotors was not an issue @ 2.8m dia but with the neos producing good power so much lower good blade design and angles is needed , so I suppose the basic thing I need to read is RPMS/Wind Speed . Amanda , could you use two boards to get the extra chanel as wind speed as I can read amps and watts and the logging might have to be a digital camera with a big memory card anyhow I will leave it at that thought ... Regards and thanks to both of you for help and input on this topic..Phill...
PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits
 
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