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Solar / Re: Now I know what you were talking about with DC
« Last post by joestue on Today at 06:32:21 PM »
you may be able to use a RCD snubber for your breaker.

a diode and capacitor across the breaker's contacts. a resistor across the diode.

the diode is needed so that when you close the breaker, the capacitor does not discharge through the circuit breaker contacts, which would kill them quickly, instead it discharges through the resistor.

the diode needs to be rated for the currrent flowing through the circuit at the time its opened, but you can get away with a much smaller diode. like 3 amps for a 15 amp circuit because the time is so short. but if you go with too small a diode, it just might explode.

the capacitor needs to be large enough to keep the volts across the breaker low enough, long enough, for the breaker to open.

so if you have 15 amps flowing, and you need to keep the volts below 50 for at least 1 millisecond, you need 15 amps times .001 second divided by 50 volts. so that's only .0003 farads, or 300uf. but it has to be rated for the open circuit voltage of your system. so 450 volts maybe. such a capacitor will be about an inch in diameter and 2 inches long.  you can probably find a few of them of similar ratings in a plasma tv.
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Wind / Re: the safeiest diy wind turbine
« Last post by joestue on Today at 06:25:37 PM »
george if you can find an induction motor you can make a synchronous generator from it. add slip rings and buy a 16$ three phase ac generator regulator off ebay.

I don't think it would take but half an hour with a real milling machine, to mount the rotor on V blocks and machine two slots or 4 slots in the rotor. the location of the slots is not critical and you can either skew them 3 degrees or you can make them all a different width to help with cogging. a dovetail cutter or single point thread mill can be used to cut a slot in the edge of the tooth so you can hammer a piece of fiberglass (you could use a piece of scrap circuit board material) to restrain the coils.
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The 57.1v limit is for legal reason's. It's 60v - 5%.
If you fail to equalize the string it will appear to be fully charged, but the string capacity will drop and sulfation will occur.
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Wind / Re: the safeiest diy wind turbine
« Last post by super64 on Today at 06:21:37 PM »

Not to Australia it appears and a 120V, 60Hz unit isn't going to be much good to me.
Our single phase power is the same Voltage as your 3 phase. Our 3 phase starts at 415v and goes up from there.

I wonder why the US went with a low voltage instead of a Higher one? 
From what I understand, 110V will still kill you.

am not in the US anymore but where i live it hot so my house have over 8 AC units so my house wiring is a 3 phase i think 720volt each phase goes to a sperate circuit one phase for the ac units one for the lighting and one for power sockets.

back to you i dont think your socket is 415 volt becuasue no appliances other there work on that voltafe
it says that austrlia is 220
https://www.tripadvisor.com/Travel-g255055-c120179/Australia:Power.And.Appliances.html

anyway dont worry to much fron the voltage and frequancy .

most appliances today have a self regulated self voltage switching AC to DC power supply .

trust me i used to do alot of camping for long periods of time .

and my camping is kinda of moving the house to the outdoors  ;D

TV, Fridge ,chest frezzer , blender, Microwave you name it.

and the best generators out there dont give a pure electricty once something turn on the voltage ,freq drops alot and its was all working fine .

the only thing that dont like dirty electricy are flourcent light and led thats about it



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Controls / Re: One way AC
« Last post by joestue on Today at 06:08:31 PM »
if you have a 120/240v inverter, you can utilize a current transformer and spdt switch for each breaker.

next you need a computer with simple algorithm to try and find a combination of loads that equals the incoming power supplied to your inverter. this is harder than you think. I believe it is np hard, meaning you might need something more than an arduino--you literally have to try adding up every combination of loads to see which one best matches the power available. and there's a lot of combinations.

also the inverter has to be large enough to handle the largest load. it also needs to remain in synchronization with the grid so that when you switch a motor or transformer load from the grid to the inverter and back, it doesn't have a huge current spike during the process.

a smart UPs such as APC's line of them, will maintain grid synchronization but remain on the battery if the input voltage is below 90 volts. this is simple to construct, but the problem is the 24v system in apc's smart ups sine wave inverter consumes about 20 watts no load for their 1KW inverters. but this is probably the cheapest way to build such a system.
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Wind / Re: the safeiest diy wind turbine
« Last post by super64 on Today at 05:46:41 PM »

I have one of those little toy generators. The mixture screw fall out and I couldn't get another one. I did manage to pick one up from the side of the road a while back and got the screw I needed.  I couldn't bear to chuck out what otherwise looked like a good Unit.  Now I have something I can do with it :0)

I have been looking for literally years to find a reasonably priced Belt Drive Gen head. Can't even find a Chinese ST type hereexcept for people selling them for more than I could buy a whole name brand gen set for.

hello george.

You can get the whole carb less than 15usd shipped thanks to china .

http://www.ebay.com/itm/Carburetor-2-Stroke-Pocket-Rocket-Dirt-Pit-Bike-Carb-47cc-49cc-Mini-Quad-Chinese-/221181716888?hash=item337f752998:g:TfMAAMXQiM5RAkSf&vxp=mtr


but dont try to revive an old chinese motor .
its made from pot metal and usuly the internal parts do wear very fast (less than 300 working hours )

now for disasmmbely of the unit follow this link .

you need a rubber hammer and a bearing puller.

https://www.youtube.com/watch?v=bFVDrVqnAJM


https://www.youtube.com/watch?v=bFVDrVqnAJM


these units are great as a back up genertor or for the out doors just like a single use camera. its less than 100 usd new anyway.

just dont store any gas on them .

put some oil in the spark plug hole.

and if you use it dry it from gas and spary some wd40 inside the tank.

i think i mentoined earlier that in order to convert it for other use you need some machining .

the genertor head and the engine share the middle section
removing the engine part and using the shared engine block will do the trick

https://www.youtube.com/watch?v=b91HbqiNXmc

https://www.youtube.com/watch?v=b91HbqiNXmc

i know i keep saying i will post some pictures but i keep everything over my brother house.

if you are looking for more wattage look for used robin or suburu genertors


you will find alot with bad motor and perfect alternator .

other genertors (with brushes ) uses an AVR (automatic voltage regulator )

This avr keeps the voltage/Hz regulated by deceresing the excetion field in the rotor .

but brushes need to be replaced every 300 hours or so .

again the good thing of the genertors is that they produce usable AC power with any extra devices.

they dont need an inverter and they dont need to be synced with the grid like a normal induction motor .

somehow the rotor keep some current inside and once you turn the motor the rotor charges wirelessly

hope this help if you need any more information please let me know


 
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Solar / Re: Now I know what you were talking about with DC
« Last post by george65 on Today at 05:35:15 PM »

I had a double Gang breaker lying round so I switched both the pos and the neg into the inverter.
last night I thought there is no break in the circuit itself If I want to change something. I thought I'd put another breaker in series between the panels so I could cut the power before the output leads.

Put one in last night and went out today and for no particular reason, thought I'd switch it off.
As soon as I flicked it, I could hear an internal arc for about 2 Sec. 
OOPS!  Don't want to do that unless I have to or no more switch!
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Wind / Re: the safeiest diy wind turbine
« Last post by george65 on Today at 05:15:37 PM »

Not to Australia it appears and a 120V, 60Hz unit isn't going to be much good to me.
Our single phase power is the same Voltage as your 3 phase. Our 3 phase starts at 415v and goes up from there.

I wonder why the US went with a low voltage instead of a Higher one? 
From what I understand, 110V will still kill you.
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Controls / Re: One way AC
« Last post by george65 on Today at 05:07:33 PM »

Yes, way too messy, expensive, bulky, heavy and everything else for my application.

A switch is probably the easiest option if not the most efficient one to just break the connection when I am generating and don't want the power to go the wrong way.
Maybe there is a way to sense that and do it electronically as it would be all I need. Power would be in the lin all the time, just have to sense which way it was going.
Otherwise a manual switch would be better than nothing.
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Controls / Re: One way AC
« Last post by joestue on Today at 04:59:26 PM »
one way roller clutch between two synchronous ac generators. but that is just messy.

another way to do it, but will probably only work with two three phase systems, is a three phase rotary transformer connected to a dc servo motor.
they actually make these things in 1 gigawatt sizes.. there are several that are used to connect the american and canadian ac grid.

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