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Need help on how to regulate voltage
By unclebuck68, Section Homebrewed Electricity Posted on Fri Jul 18, 2003 at 08:07:15 AM MST
Please help!

I'm planning to build a three phase alternator windmill. I'm thinking of using the diode rectifier from a Chevy alternator. One question, how can I regulate the voltage? I dont understand how the voltage regulator in the Chevy alternator works and how I can adapte it for my use? I'm also looking for information on how to build the furling system.I looked and did a search, and couldn't find enough information on how to build it. Thanks in advance. Mike

Need help on how to regulate voltage | 9 comments (9 topical)

Re: Need help on how to regulate voltage (none / 0) (#1)
by DanB on Fri Jul 18, 2003 at 08:32:08 AM MST

Hi Mike -
You need not regulate the voltage, the batteries will do that for you. You may want a charge controller which will put a load on either the windmill, or the batteries once the batteries are full charged to prevent overcharging.

Regarding the furling system.... at this point I cannot think of a detailed description on the web. (I'm sure there is one out there). Hugh Piggott's is great, I'd go to his website and either buy his plans, or get his book "Windpower Workshop" - it's all very helpful.

There was some discussion about this recently:
http://www.fieldlines.com/story/2003/7/9/21444/13286

Re: Need help on how to regulate voltage (none / 0) (#2)
by troy on Fri Jul 18, 2003 at 09:55:56 AM MST

As far as voltage regulation, that depends on what you're doing with the juice. If you're charging a decent sized battery bank, the batteries will draw down the output voltage of the mill to the battery level. If you have an extremely high voltage mill (say over 50 volts at speed) and a 12 volt battery bank, you might run into problems. But if your mill makes voltage more in the 15-30 volt range, no problem. You don't have to regulate the voltage at all.

However, your batteries will eventually get charged, and then you have to switch the current to a dump load, a heater or light bulbs or whatever, appropriate for the voltage and current. There are commercial units to do the switching or some home brew designs that you could build if you're handy with a soldering gun.

So if you could give a bit more info on what you're doing with your system, we can be more helpful.

Best regards,

troy

Re: design issues with how to regulate voltage (3.00 / 0) (#9)
by Elnav on Mon Dec 10, 2007 at 12:46:20 PM MST

Troy wrote:
If you're charging a decent sized battery bank, the batteries will draw down the output voltage of the mill to the battery level. If you have an extremely high voltage mill (say over 50 volts at speed) and a 12 volt battery bank, you might run into problems. But if your mill makes voltage more in the 15-30 volt range, no problem. You don't have to regulate the voltage at all.

My background is working with relatively larger systems where the charging source does fill the batteries completely. I'm accustomed to needing several hours at float potential to ensue all of the lead sulphate is reversed. Failure to provide this "float voltage" for sufficient time results in accumulations of lead sulfate which eventually leads to reduced storage capacity. In extreme cases it leads to premature battery bank failure.

There is a question in my mind whether or not the battery will sulfate under sustained under charging due to wind generator bein unable to bring the charge up enough to trigger the load dump regulator.

This exact problem has plagued the trucking industry for years. The relatively small OEM alternator fails to bring the battery up to full charge when all those lights turn on. Some trucks have a base loading of 70 amps due to all the lights they put on for "personalizing" the rig. That doesn't leave enough to keep the battery full and it sits at 12.2 - 12.8V and sulfates accumulates.
Elnav

[ Parent ]

Re: Need help on how to regulate voltage (none / 0) (#3)
by Barnac on Fri Jul 18, 2003 at 10:33:18 AM MST

What do you mean by voltage regulation ? What is the difference from voltage rectification ? As I understand it votage rectification is the process of making AC votage become DC voltage. While voltage regulation is the process of controlling the voltage so It will show little or no voltage variation. Just to clarify the termilogy used here, I am francophone so maybe you guys use different terminolgy.

[ Parent ]

Re: Need help on how to regulate voltage (none / 0) (#4)
by Jimbob on Sun Jul 20, 2003 at 12:31:46 PM MST

There are two types of common voltage regulation designs- series & shunt. The precision series type that is commonly used in a regulated linear type DC power supply maintains a preset voltage irregardless of the load (current) & burns off the over-voltage (voltage above the preset output voltage) in the form of heat. The shunt type simply loads the output down to the desired voltage level, but usually requires a series resistor as well.

Unless your battery storage is undersized with regard to your generator output, you do not need a voltage regulator. The beauty of a battery system is it will draw a variable load during charging & maintain approximately 10% regulation. One does not need a precision regulator. Once the batteries are fully charged, a resistive load bank can be switched in circuit to drawdown the excessive voltage & prevent overcharging the batteries. A good resistor bank is a 24vdc hot water heater. Some electric commercial water heaters that are fast recovery type makes use of a lot of heater elements. These heaters are rated for either 480 or 240 vac & most are 3-phase. One could use either 240 volt or the best are 120 volt elements & rewire the water heater to single phase. If an elements is 1000 watts at 120 volts, at 24 volts it will draw 200 watts. If you have 6 elements, that is a 1200 watt load. If 12 elements are used, that is a 2400 watt load.

I am new to this power generation for the home owner business, but have built large power generation plants. Others can point you to some load shedding type devices to achieve your needs. I am modeling my system to use that commercial hot water heater. Summers have less wind vs the winter where I live. If I have a situation of excessive hot water during the winter, I will divert it to heating my house. I doubt this issue will arise during the summer. I also will build my own controller to like mil-spec standard for ultra high reliability. (I have designed for NASA once).

Re: Need help on how to regulate voltage (none / 0) (#5)
by scoraigwind on Sun Jul 20, 2003 at 03:48:14 PM MST

Hmm.

If an elements is 1000 watts at 120 volts, at 24 volts it will draw 40 watts. The current and voltage both go down so you only get 1/25 the power out.

Power = Vsquared /R
Hugh Piggott http://www.scoraigwind.co.uk
[ Parent ]

Re: Need help on how to regulate voltage (none / 0) (#6)
by Jimbob on Mon Jul 21, 2003 at 07:47:41 AM MST

Resistance per ohms law of a 1000 watt @ 120vac heater (resistor) is 14.4 ohms. At 24 volts, the 14.4 ohm element would draw 1.66 amps. 1.66 amps times 6 elements is say 10 amps. 24 volts x 10 amps is 240 watts. I miss calculated. Tnx for the correction. I will use lower resistance elements to get to the 1200 watt load.

[ Parent ]

Re: Need help on how to regulate voltage (none / 0) (#7)
by troy on Mon Jul 21, 2003 at 11:46:02 AM MST

Dear Jimbob and others,

Here's a source with specifications and prices for ready made low voltage heating elements for water heater. Convert away!

Best regards,

troy

http://www.kansaswindpower.net/water_heaters.htm

Use one or more of these elements as a diversion load with Trace C35, C40, C60, TC60 controllers. They fit most standard water heaters with screw-in elements. An adapter is used for the square flange type element. The dual 12/24 element has two separate 25 elements. It can be wired for 25 amps or 50 amps at 14.5 volts or 25 amps at 29 volts. The dual 24/48 volt element has two separate 30 amp elements. It can be wired for 30 or 60 amps at 29 volts or 30 amps at 58 volts. Order enough elements with a total current draw greater than your charging system's maximum output, but no more than about 75% the maximum amp rating of controller. 150 watt hours will raise 1 gallon of water about 60º.
D380 12/24 volt Dual 25 amp 3 lbs $65
D381 24/48 volt Dual 30 amp 3 lbs $65
Square Flange Adapter 1 lb $20

[ Parent ]

Re: Need help on how to regulate voltage (none / 0) (#8)
by Andrew on Mon Jul 21, 2003 at 02:29:15 PM MST

I did somewhat the same for a heating element load...

I used the rods from a water heater...

Each measuring 2.2 ohms...
Put them in parallel across a board
I made a bar that was attached to some all thread...
The bar would slide across the resistive rods to determine the right resistance (think of a really big potentiometer)
And to get the right load, I would simply turn the all thread in a direction...

Like 120v it would be the farthest away, and 12v it would be pretty close to the top...

Get it?

The bar is acting like like the other end of the circuit...

And when it is closer to the opposide side, the resistance will be lower, meaning more load....

-Andrew

[ Parent ]

Need help on how to regulate voltage | 9 comments (9 topical)

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