# Wind Generator Design

##### New Member
Well my dad and I were talking about creating a wind power generator for the house. I know to use a car Alternator, and a Power Inverter for everything, but I wanted to know some more details, and seeing how I dont even know the name of it, I think I might want to ask the forum before I spend hours on google sifting through windmills

I would like it to be able to go into the power inverter (12V I guess?) and step it up to 120AC. We have a little one for a car so I know IT can be done. maybe I will get some car batteries and have it hook up there and charge those then use that as a power source for our very energy craving house for about 2 minutes Actually I would use it for myself. I know how to wire up the house and stuff, but really just wanting to know the design and etc of one.

Thanks

##### New Member
I know that if you spin a motor it generates voltage right? So if I put huge blades on a very large motor (3Amp No load) I could use that right?

#### Nigel Goodwin

##### Super Moderator
There are lots of links to wind powered generator sites in this forum, go and study some!.

You do need batteries, without a storage medium it's pretty useless.

#### Hero999

##### Banned
Your best bet is to try to cur your power consumption first, before you mess around with wind turbines.

Car batteries aren't really much use as they aren't designed to be discharged much.

##### New Member
Hmmmmmm

What about a massive capacitor bank

#### Nigel Goodwin

##### Super Moderator
Hmmmmmm

What about a massive capacitor bank
You couldn't afford them, and don't have enough room!.

Yes, but you should use ones specifically designed for deep discharging, not just cheap car ones.

However, if you can get hold of cheap car ones it will give you a chance to test the practicability of the idea.

I think I like the Lead Acid batteries, and I could use the ones that my HS robotics team uses (they pull up to 100A). They are only 20$. #### Krumlink ##### New Member Now for the Power generation part: How to produce around 12 Volts? I could use several things for power generation, but do you know of any good ones? Also, for the inverter, I could use a part, product, schematic, etc. #### Hero999 ##### Banned Ideally you want a higher voltage than 12V, if you want to drive an inverter from it,. Generally the higher the voltage the better, 48V would be ideal as it's just about safe to touch with dry hands but failing that you could easilly settle for 24V. For safety's sake, earthing both the DC and AC side is also a good idea as it won't float at a stupid voltage if the mains acidentally comes in to contact with it, it'll just blow a fuse/RCD/GFI and it'll make lightning protection circuitry easier to implement too. Last edited: #### audioguru ##### Well-Known Member Most Helpful Member When the wind blows hard then the current will be 30A or more and the generator will burn out or the blades will fly apart. The battery might become severely overcharged or might boil. You need a charge controller with something to limit the current from the generator. Then it stops charging when it detects that the battery is fully charged. You also need something to limit the RPM of the blades. #### Krumlink ##### New Member audioguru said: When the wind blows hard then the current will be 30A or more and the generator will burn out or the blades will fly apart. The battery might become severely overcharged or might boil. You need a charge controller with something to limit the current from the generator. Then it stops charging when it detects that the battery is fully charged. You also need something to limit the RPM of the blades. The motor I am thinking of is REALLY torquey, so that wont be a problem. Michigan is very wierd... #### mynameisdan ##### New Member For limiting the speed of the blades you can use a magnet brake. #### Krumlink ##### New Member mynameisdan said: For limiting the speed of the blades you can use a magnet brake. So would I just put magnets behind the blades that are mounted on the motor, far enough away not to affect the motor? #### mynameisdan ##### New Member Try running a magnet over a peice of metal. The faster you go, the more you feel it's resisting. The further away your magnet it, the faster it will allow you to go. The old trick is a dropping a magnet down a copper pipe. #### Krumlink ##### New Member Ok thanks, I will take that into consideration. Thanks #### jpanhalt ##### Well-Known Member Most Helpful Member mynameisdan said: For limiting the speed of the blades you can use a magnet brake. It might be easier to make the blades with controllable pitch. So-called constant speed propellors for aircraft have such blades. Second, do not underestimate the drag force against your windmill. A free-wheeling propellor has a drag force approximately the same as a flat plate of the same area as the propellor's arc. Thus, an eight foot propellor (arc area about 50 ft^2) feee-wheeling in a 30 knot wind would have a drag force of about 200 # (See: http://www.sailingusa.info/cal_wind_load.htm). You may want a brake on the prop to stop it from turning in a strong wind or a method of turning the windmill parallel to the prevailing wind. Feathering the blades also acts as a brake and further reduces drag compared to leaving the blades at their normal pitch. John Last edited: #### Hero999 ##### Banned If you want to be clever you could design a turbine that eneables you to change the angle of the blades to limit the RPM. #### Krumlink ##### New Member I was thinking about a system of solenoids with magnetic brakes on the end that could slow it down with a push of a button About the Batteries, what: Voltage Amperage Should they be? Also, what should I use to generate the voltage? #### Super_voip ##### New Member Krumlink said: I think I like the Lead Acid batteries, and I could use the ones that my HS robotics team uses (they pull up to 100A). They are only 20$.
Or you could use AAA nicads they can supply a lot of current as well, really what you need is old telephone exchange batteries, they can supply a lot of current for a long time.

##### New Member
Super_voip said:
Or you could use AAA nicads they can supply a lot of current as well, really what you need is old telephone exchange batteries, they can supply a lot of current for a long time.
AAA NICADS may be too small for this scale. I am talking a few amps per hour, more than any NICAD for that matter could/would supply without overheating.

I like the Lead acid idea, and so does my Family.

I really need a generator now!