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Forum Index : Windmills : Electronics question
| Author | Message | ||||
| leftcliq Regular Member  Joined: 21/07/2012 Location: AustraliaPosts: 51 |
Hi Guys, OK, I have a 60S Smart Drive motor hooked up to a bridge rectifier then into a step down transformer. Without the transformer I am getting 466V using a power drill but with the transformer I get nothing. I am using a resistor in series. My question is, what do you guys use to convert the voltage output to say 12V with a few amps? Regards, Dale. |
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| leftcliq Regular Member Joined: 21/07/2012 Location: AustraliaPosts: 51 |
I have answered my own question as transformers need an AC voltage to cause fluxuations in the magnetic field. CAn anyone recommend a good dc-dc converter? Regards, Dale. |
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Madness Guru  Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
You could use a transformer in the circuit before the bridge rectifier. Although as it is a 3 phase set up you will need one on each phase. Can't you rewire the stator to suit your voltage requirement? There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| leftcliq Regular Member Joined: 21/07/2012 Location: AustraliaPosts: 51 |
Hi Madness, Yes, thanks for that. I'll try that. |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
You are playing with danger taking this approach, there is no need to make HIGH voltage power and then reduce it back to low voltage. Do it the correct way and re-configure the stator wiring to produce power in the voltage range you require (low voltage with higher amps) High voltage from a generator can KILL you or anyone else for that matter, and do you really want the risk of this thing flogging around in all weather conditions and run the risk of perhaps killing someone........There is good reasons why we build generators the way we do, and safety is one main part. Using a transformer will add losses to the system, and as you will find its hard enought to make power in the first place without introducing losses that dont need to be there. Have you read these pages, as they should show you how to do it the correct way. http://www.thebackshed.com/windmill/FPRewire.asp Pete. Sometimes it just works |
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BobMann Senior Member  Joined: 30/06/2011 Location: United StatesPosts: 134 |
This why we made the Smart Controler MPPT to make these PMAs work better in the real world of wind. When you start to add transformers to these stock 60s stator is like putting brakes on the turbine. You can feel it by just adding a 1 ft arm on your PMA with a handle. Now crank it up with out your transformers now add them redo the test. Here is a Vid on how things work MPPT test Bob Mann |
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| leftcliq Regular Member Joined: 21/07/2012 Location: AustraliaPosts: 51 |
BobMann, Can you tell me where I can get one of these controllers? Downwind, If I rewire the stator, will I lose the cogless effect of the 60S? Do I need another rotor? I have read the link you provided but it wasn't enough information, what amps are generated and voltage etc. But I'll try the 36Pole 4X3C setup and see how it goes. Is there anyone I could actually talk to or to gain first hand advice from who has modified this 60S stator? I am always weary about cutting the stator wires as I don't want to stuff it up. -Dale. |
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| leftcliq Regular Member Joined: 21/07/2012 Location: AustraliaPosts: 51 |
I know the cogless effect on the 60S is due to the shaped poles but will change the wiring effect this? -Dale. |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
No it won't, the cogging is an interaction between the steel poles and the magnets. The windings have no effect until there is movement, cogging is at it's worst at 0 RPM. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
You are a little wrong in your theory about cogging, because the cogging effect is there regardless of how the stator is configured, as Madness quoted its due to the magnets attracting to the steel core, so changing the stator wiring will not effect the cogging one little bit. If you want more information about stator rewires to suit you, then you need to provide clearly what you want to acheive, like output voltage, what rpm you want cutin to be around, what blades you intend to use, what diameter blades, etc. Changing the stator wiring is not that hard, and once you sit down and study the wiring and get a clear picture in your head its an easy task, although it takes a little time to do, the worst part is stripping the coating off the end of the cut stator wires before you can solder them, i find a broken hacksaw blade good for this as the wire fits into a tooth gap and srtips rather easy with a few passes on each wire. My advice to you is not to get too hung up on cogging and worry more about getting the stator rewired to suit and the mill built and in the air, cogging is the last thing you need to worry about and might or might not effect your mill greatly, it depends on your wind and blade type and you can sort the cogging out later. If cogging effects your mill to the point of it not working then you have bigger problems than just cogging. Its been years since i rewired a stator so may not be the best person to talk to on it, im sure there is more recent members that still play with lower output F&P alternators. Besides a few forum searches should turn up a mountain of disscussions of the F&P as they have been around for more than 10 years and many used them in mills back when Jesus still wore short pants. Pete. PS- you dont need any fancy controller with the F&P if you get the rewire correct, the more crap you add to the system to fix a poor design in the first place just adds greater losses to the overall system. Sometimes it just works |
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fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Dale, First up , play with your 60s and learn, but they are the worst of all for performance so dont expect to get 500w , the 80s are common and good but the 100s which are a bit rarer are the best. If you want to de-cogg then twist the poles , if you don't want to worry about de-cogg run GOE222 blades. But I was't around when JC wore shorts , and Pete is right you dont need fancy crap for a F&P .. Good blades is the best starting point and they can be moved as you move. PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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| leftcliq Regular Member Joined: 21/07/2012 Location: AustraliaPosts: 51 |
Hi Downwind, I'm trying to create 48V at 2 Amps at the smallest amount of RPM. Approximately 100 - 200 RPM. According to the EcoInnovation manual, page 64: I can achieve this with a 60S -48V Star. I have the 60S and my thoughts were to step this down with transformers. Going by the info above, I won't be using transformers for safety reasons and the amount of force required to turn the shaft. Sorry to sound stupid, but how do I configure this 60S to only 48V without transformers? -Dale. |
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| leftcliq Regular Member Joined: 21/07/2012 Location: AustraliaPosts: 51 |
Hi Fillm, Thanks for the advice. Any help right now is really appreciated. I wanted to walk before I could run, thats why I got the 60S. I get 466V at aprox 500RPM with the 60S. I tested this with a handheld drill on the 12mm female shaft. Way too much and more then what I wanted. -Dale. |
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| BobMann Senior Member Joined: 30/06/2011 Location: United StatesPosts: 134 |
Dale for a Newbie I would say just do as the old school says for now it works and you will be up and running. Bob Mann |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
[quote]Sorry to sound stupid, but how do I configure this 60S to only 48V without transformers? [/quote] If you go back to the page i linked in a earlier post it shows you how to change the stator wiring. What Glenn has suggested is 2x7C in star for 48 volt. http://www.thebackshed.com/windmill/images/42Pole2X7C.gif This is the easiest of wiring changes to make as what you are doing is dividing the stator in two halves and putting both halves in parallel with each other. This will reduce the voltage by half and double the amps output for any given rpm. So result is volts down and power output up. Label the stator coils 1,2,3,1,2,3........all the way around starting from the 3 existing wire terminals, then you will see all the "1s" are connected in series with each other, and the same for all 2s, and 3s, what you need to do is find the point where you have even groups of all 3 coils on both sides (2 lots of 7 coil groups or 21 coils a side), then cut the wires between the two halves and rewire it as per the diagram above, full details is on the main page i linked earlier. Pete. Sometimes it just works |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Be very careful with when testing like this as the output is lethal. Open circuit voltage will be higher than with a load connected. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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