Author Topic: Ideal voltage out of altenatore  (Read 936 times)

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XeonPony

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Ideal voltage out of altenatore
« on: October 20, 2017, 07:41:55 AM »
I am planning on making a 48v alternator for my wind turbine, The idea is to run wild ac down the pole to the house, then there I will feed it into a 3 phase auto transformer to match the current 12v system.

Over load controls and  dump loads will be on the 48v ac side. but here's my problem, I need to know what the general ideal voltage from the turbine would be so I could start fleshing out the Auto transformer.

For the dump load I want to use a Voltage controlled oscillator  to drive a scr to the water heater, and if the water heater is off a air heater bank will be active so there will all ways be a dump load active.. So in short a PWM dump load controller

Or even 120V.  Right now I am just looking for ideas. Still yet to make the geo blades, my air X recently was killed in the wind storm thanks to a failed wire inside allowing to vastly over speed, the mags tore off the rotor and mangled the stator!

I can repair the rotor system, but the stator can be purchased rather cheaply, but as stated want to remove the circuitry and run it right to the house and do all the controlling from there.
Ignorance is not bliss, You may not know there is a semie behind you but you'll still be a hood ornimant!

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joestue

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Re: Ideal voltage out of altenatore
« Reply #1 on: October 20, 2017, 10:06:43 AM »
why not wind your alternator with 2 sets of coils.

at a given (fixed) rpm:

2Y makes 3.46 v
2D makes 2 v
1y makes 1.73 v
1D makes 1 volt.


So 12 leads from the tower feed into 2 sets of wye/delta relays.

The relays feed two sets of 3 phase rectifiers, and the output of both rectifiers gets fed into a dpdt relay, such that the rectifiers are in series or in parallel.


I would wind an alternator for a voltage such that regular off the shelf heating elements will be a good match for the power you can get.

XeonPony

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Re: Ideal voltage out of altenatore
« Reply #2 on: October 20, 2017, 08:59:06 PM »
well plan 1 is to use a 1 to 3 step up planetary gear box and use a 1760 rpm induction motor and see how that works.

if my math adds up  8 foot diameter prop driving at 3-400 RPM should run the motor at the ideal speed.

Planetary will offer high efficiency. but not sure how a capacitor regulated induction gen will perform till I can make a normal alt.
Ignorance is not bliss, You may not know there is a semie behind you but you'll still be a hood ornimant!

Nothing fails like prayer, Two hands clasped in work will achieve more in a minute then a billion will in a melenia in prayer. In other words go out and do some real good by helping!

joestue

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Re: Ideal voltage out of altenatore
« Reply #3 on: October 20, 2017, 10:48:59 PM »
well plan 1 is to use a 1 to 3 step up planetary gear box and use a 1760 rpm induction motor and see how that works.

if my math adds up  8 foot diameter prop driving at 3-400 RPM should run the motor at the ideal speed.

Planetary will offer high efficiency. but not sure how a capacitor regulated induction gen will perform till I can make a normal alt.

most motors are 2 sets of coils, pull the hidden star point out and you get the 1,1.73,2,3.46v ratio i mentioned, depending on how you hook it up.

the ideal voltage is a trade off between bearing and windage and gear box losses. might use diesel fuel in the gear box instead of 80w-90 gear oil (which is actually similar to 10w-30 in viscosity) to cut down on bearing losses.

planetary gears are only more efficient in that the bearing loads are equalized and you don't need preloaded bearings to rigidly hold the shaft in place. for wind turbine applications you can probably reduce the preload in a vehicle rear end and get your 3:1 gear ratio, and directly support the turbine blades by the rear end, no need for any other bearings.
« Last Edit: October 20, 2017, 10:53:40 PM by joestue »

george65

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Re: Ideal voltage out of altenatore
« Reply #4 on: October 21, 2017, 02:56:30 AM »
might use diesel fuel in the gear box instead of 80w-90 gear oil (which is actually similar to 10w-30 in viscosity) to cut down on bearing losses.

I wouldn't use Diesel as a lubricant for anything. In it's modern form it's very dry and really a terrible lubricant.  Something like 2% veg oil or 2-stroke oil improves the lube value of diesel MANY orders of magnitude. For get the numbers but the test I saw showed straight and the 2% to be absolute chalk and cheese.  Much better lightweight oil option would be Transmission fluid. You could even break it down with Diesel but I don't think it would make much difference.  New Veg oil is also pretty light if it were not going to be used below 10oC. After that it does tend to get a bit stiffer.

Manual gearboxes in cars now run Tranny fluid as well as autos.

XeonPony

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Re: Ideal voltage out of altenatore
« Reply #5 on: October 21, 2017, 09:08:13 AM »
I would bother with oil at all! a good high quality low temp grease with molybdenum sulfide in it for wear reduction in high pressure points.

High quality greases have lower over all drag coefficient then oil and better lubricating properties, and you gain further by no longer needing friction seals as you would using any liquid lubricant.

and one can easily set up a nipple at the tower base and have it to grease the unit, but assuming a good bi yearly maintenance cycle just as easy to service all components then. Here it can get down to -60 but average is between -40 to -20c (Really hoping it keeps to the -20 this winter!)

I'm thinking of embedding a nichrom strand around the blade to de-ice it on calm periods. but for now need to flesh out the plan care fully.

So far:

Blade: 4 to 5 foot geo 222
Planetary gear box if needed
High pressure quality lithium grease where needed
8 gauge wire down tower
Min voltage 48v max 240v AC

33 foot tower free standing on a 46cubic foot cement base (Too big of a base? Or could I do with 22 cubic feed)

Average wind speed of 8 to 14mpH  (  https://weatherspark.com/y/4404/Average-Weather-in-Yorkton-Canada-Year-Round )

So if all numbers add up and care full design I should be able to easily get average of 500 watts when running, like this morning there is a constant steady wind at 10mph
Ignorance is not bliss, You may not know there is a semie behind you but you'll still be a hood ornimant!

Nothing fails like prayer, Two hands clasped in work will achieve more in a minute then a billion will in a melenia in prayer. In other words go out and do some real good by helping!

tanner0441

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Re: Ideal voltage out of altenatore
« Reply #6 on: October 21, 2017, 09:18:30 AM »
Hi

A good all purpose light oil I've found is Spindle Oil. It is sold in very small quantities in little tins in the UK as 3in1 oil. A firm I was at we used to buy it in 5 gallon drums for a Churchill crank shaft grinder.

The water content in diesel would also be a concern to me.

Brian.

joestue

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Re: Ideal voltage out of altenatore
« Reply #7 on: October 21, 2017, 01:17:44 PM »
So if all numbers add up and care full design I should be able to easily get average of 500 watts when running, like this morning there is a constant steady wind at 10mph
At that power level, I would make a synchronous motor from a 2-3 hp induction motor.

dnix71

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Re: Ideal voltage out of altenatore
« Reply #8 on: October 21, 2017, 04:34:23 PM »
I'm with XeonPony on the moly sulfide grease recommendation. I used to repack vacuum cleaner bearings with it. It doesn't come out if the bearings are properly sealed and won't burn or dry out. If your bearings are not sealed to the weather then you need an oil cup/felt pad and sewing machine oil. Sewing machine oil is full synthetic with no additives, not cheap but won't burn or attract dirt and is non-toxic.

Moly sulfide grease was originally used for automobile cv joints and may still be sold in small tubes for that purpose.

Mary B

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Re: Ideal voltage out of altenatore
« Reply #9 on: October 21, 2017, 04:47:39 PM »
My 35' ham radio free standing tower uses a 5x5x7 foot base! There is a LOT of leverage on the base in high winds!

I would bother with oil at all! a good high quality low temp grease with molybdenum sulfide in it for wear reduction in high pressure points.

High quality greases have lower over all drag coefficient then oil and better lubricating properties, and you gain further by no longer needing friction seals as you would using any liquid lubricant.

and one can easily set up a nipple at the tower base and have it to grease the unit, but assuming a good bi yearly maintenance cycle just as easy to service all components then. Here it can get down to -60 but average is between -40 to -20c (Really hoping it keeps to the -20 this winter!)

I'm thinking of embedding a nichrom strand around the blade to de-ice it on calm periods. but for now need to flesh out the plan care fully.

So far:

Blade: 4 to 5 foot geo 222
Planetary gear box if needed
High pressure quality lithium grease where needed
8 gauge wire down tower
Min voltage 48v max 240v AC

33 foot tower free standing on a 46cubic foot cement base (Too big of a base? Or could I do with 22 cubic feed)

Average wind speed of 8 to 14mpH  (  https://weatherspark.com/y/4404/Average-Weather-in-Yorkton-Canada-Year-Round )

So if all numbers add up and care full design I should be able to easily get average of 500 watts when running, like this morning there is a constant steady wind at 10mph

joestue

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Re: Ideal voltage out of altenatore
« Reply #10 on: October 22, 2017, 01:09:19 AM »
it might be possible to build a self exciting system where as the rotor of a synchronous motor is fed from a stator coil. given that the torque of a motor is proportional to the flux density squared, and the flux density would be proportional to the rpm, this could actually match the cubic power curve of the wind, the problem being that you need a square relationship between the coils to get the current to flow into a constant voltage load.

1 turn might be good for full load, but you would need 9 turns of wire for 1/3rd the windspeed.

the existing ratios of 1, 1.73, 2, 3.46 from a typical 12 wire motor should be able to cover this ratio if some additional help is provided in the form of an auto transformer or rotor current control is provided.

for the low end of windspeed and rpm, a dc-dc boost converter is the obvious choice, since it only needs to operate for a fraction of the peak power. since the flux density of the entire system will be proportional to the rpm, there should not be any transformer start up problems, so an auto transformer for the higher voltage/rpm/wind speed is probably the most efficient way to transform the voltage and match the load.
« Last Edit: October 22, 2017, 01:13:48 AM by joestue »

XeonPony

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Re: Ideal voltage out of altenatore
« Reply #11 on: October 23, 2017, 09:02:16 AM »
Will this work: My main pole is a light stand pole that is 22 feet, it will be securely mounted to a large cement block, but for maintenance I was thinking a sch80 2-1/4 inch pipe on a hinge system at 22 feet.

On the top of the free standing light stand have a 1/2" steel pivot system with 3 * 1/2" bolts to secure it, will that hold up? or stick with 10 foot of pipe with a 9inch flange system with a 5 bolt pattern with 5/16 316L ss bolts.

Ignorance is not bliss, You may not know there is a semie behind you but you'll still be a hood ornimant!

Nothing fails like prayer, Two hands clasped in work will achieve more in a minute then a billion will in a melenia in prayer. In other words go out and do some real good by helping!