[hsstudent]

Basically I made my own stator and rotor, attached a hub and some blades and now I want to see what the output is..
Im thinking of connecting it to a series of light bulbs to measure what the output capacity is.

I know theres multimeters and other measuring devices that can do this....
but this is for a school project and I think the light bulbs would add a good visual to it.
So thats what Im trying to do.

I just dont know how I would wire it, with or without some capacitors, transformers, or any kind inversion...
But Im trying to stay away from buying anything and need to do it myself.

I would need to go from the rectified A/C coming out of the PMA and directly wire to a light bulb series?

Anyone!

Thanks in advance

 

[AandPDan]

Alternators put out ac, so, unless you have diodes you will have ac out.

Can you post a diagram of what you're doing?

You don't need any capacitors or anything to run some bulbs. They'd be happy on ac or dc. You don't need a transformer, keep it SIMPLE. You don't need an inverter, you already have ac.

Do you have any idea as to how much current you can supply and at what voltage?

 

[hsstudent]

Ihave 12 volts and current..dont know

My connection is simple...

Its just rectified 3 phase a/c coming out the turbines PMA

From there I have a modified heavy duty extension cable that comes out

From this end I figure Id plug in to the parelled series of 100 watt light bulbs

I figure 10 is more than enough because theres not alot of high wind and by doing more than Ill need it sort of works like a dump load
Plus its not a very strong PMA
Ill be lucky to get even 1/3 of that...as they are not large magnets

My worries are the following

#1 If I connect rectified A/C wont that be so weird that they will sort of strobelight the bulbs going dim and bright because of the a/C
Should I somehow plug into a regulator of some sort?

#2 Im kinda worried that the initial bulbs are going to blow out because wont there be such a surge of current that the 100 Watts might not be able to handle them...
Im hoping by putting them paralleed that this will prvent that from happening. Am I right in my thinking?

#3 Im worried I might do damage to the PMA that took me too long to make if I should burn a bulb or something...then the PMA will continue to produce energy that has to go somewhere. So if a wire breaks, will the energy be force to return to its source or will it work like a severed power line and dance all over the place with its ends omitting the energy..which has potential for fire.

#4 My limited thinking is telling me its already a/c (but its crazy a/c isnt it) and because its a/c the flow can only go one way...and if I align more than enough light bulbs then the current would eventually be slowed down...but how do I complete the circuit?
Its going into bulb #1, and Bulb #10 is going to connect to what?
This is what I cant figure out.

All my research is basically youtube videos and the internet..so anyone that can help I thank you so much

 

[AandPDan]

How big is this thing?

Everything depends upon the voltage output. It's going to vary depending upon speed of rotation as is the frequency of the ac. "Bigger" turbines regulate the current in the rotor (same as in a car) to control voltage if it goes too fast.

Depending upon the frequency of the ac generated you may not notice the lights flickering. The lights in your house do it 60 times a second after all.

You could use a capacitor to "smooth" out the rectified ac, or dc. Not necessary in my opinion for an incandescent bulb.

How many volts are these bulbs? 120? You'd need to generate more than 120 volts to worry about them burning up quick. They only draw 100 watts at 120 volts - look up Ohm's law. Yes, it's a bit different under ac but you'll get the idea.

You can damage the PMA if you put too big a load on it. It can overheat. You're better off starting with a small load.

You won't damage it by running it without load. Electricity needs a complete circuit for the electrons to flow. If you have an open circuit, no electricity flows, no damage. That's how fuses protect a circuit. They "open" and then no electricity flows.

AC goes both directions. It "alternates" polarity. What you do is you wire everything in parallel.

How is the alternator wired?

For your load:

You have two wires, on a lamp socket there are two screws. Usually one is brass colored and the other silver.

Take one wire and connect all the brass screws together. Use another wire to connect all the silver screws together. Do this for as many sockets as you have. All the bulbs will have equal voltage and equal current (if same wattage). If one bulb "blows" you still have the other lights running. This is how your house, car, most things are wired, in parallel.

Bulb 1 and bulb 10 both connect the same, B is the bulb (below).

------------------------------------------------------------------LINE 1
| | | |
B B B B
| | | |
------------------------------------------------------------------LINE 2

DO NOT connect the bulbs in series. In this case it's like an old set of Christmas lights. If one blows, they all go out. Don't do this (below)!

--LINE 1----B----B----B----B---B----B----LINE 2--

Hope it helps.

 

[curiousB]

When you say you made your own stator and rotor do you mean you used a car's alternator? Those are typically three phases and a diode bridge to rectify it back to DC.

The voltage output is determined by the field in the rotor. Are you using permanent magnet rotor or a wound field where you can vary current to the rotor field?

If you get a book on electric machines you'll see how this works. The math is based on calculus and electro magnetic theory. The math is not for the faint of heart but if you are taking AP Calc it might be understandable.

The power out is determined by the mechanical power in. If you want to light up 6 x 100W light bulbs you'll need 600Ws of mechanical energy to the input shaft. In fact you'll probably need over 1000W due to inefficiencies in the conversion and other system losses. By the way 1 HP is 745 watts so you'll need to apply over 1HP of mechanical power to light up the 6 bulbs. Lance Armstrong in his peak generated about 400W of power as an elite cyclist.

The voltage output will be determined by the RPM and the field current. If permanent magnets it will be simply due to RPMs.

If you are using a car alternator the diode bridge is only rated for 12VDC out so the diodes are probably good for nothing more than 40-50 volts max after which they will breakdown. So be wary of this before you overdrive the field current or max out the RPMs. Diodes typically fail to a short circuit (they effectively weld themselves).

 

[hsstudent]

Homemade Windmill anyone know how to directly wire a series of lightbulbs from PMA?

Thanks A&PDan for your help.

Here are the answers to your questions

How big?
The blade diameter is about 30 inches from one blade to the other. Its about half the size of your regular windmills which is why I know I wont be generating as near the power output as the bigger diametered blades because of the sweep area.

The PMA is a rebuilt car alternator but mine has a rotor and a stator that I made myself. Magnets could be stronger, but they are as close as can possibly be to the coils. And the coils are wrapped in a different manner as traditionally used in stators so Im hopeing that will help with hte output.

The Bulbs re your every day 100 watt bulbs, I dont think it would differ any because its going to take 100 watts either way a/c or d/c

SMALL LOAD VS LARGER LOAD
You said I should use a small load of bulbs...you said I could damage the PMA if I put too big a load on it?

But will that make a difference any?
Because if I go to small wont the energy need to go somewhere, and if its too small, then I will need some sort of dump load to divert it otherwise where will it go....
wont that damage the PMA more because theres too much energy bouncing around in a limited circuit without an escape.....
Or will it simply push the electrons out faster to create an even stronger bulb shine?
VS
If I use more than enough bulbs stacked wont that actually keep pushing the electrons and if I set them in parallel it will be like a glass of water that never really gets quite full to capacity...so I wont burn anything out - versus if I go too small wont that be like a cup I overfill with water?

HOW THE ALTERNATOR IS WIRED...
Simply have 3 phases of coils coming out of the alternator. 3 wires, and I thought I needed a rectifier..but perhaps I dont.
But I saw a video where this one guy rectified the A/C to carry his current with an extension cord..so thats what I am going to try to do.
Is this wrong?

Thanks for the time it took to help with these questions

 

[hsstudent]

curiousB

CuriousB
You asked a few questions..heres my answers.
thanks for the help

I made my own permanant magnet alternator by winding my own coils and making my own rotor and making adjustments to a regular cars alternator

If you can help with any of the 4 concern Ive listed above or have anything else to add, Id greatly appreciate it.

Thanks guys

 

[AandPDan]

How big? The blade diameter is about 30 inches from one blade to the other. Its about half the size of your regular windmills which is why I know I wont be generating as near the power output as the bigger diametered blades because of the sweep area.

OK. Smaller turbine rotates faster too, good for an alternator.

The PMA is a rebuilt car alternator but mine has a rotor and a stator that I made myself. Magnets could be stronger, but they are as close as can possibly be to the coils. And the coils are wrapped in a different manner as traditionally used in stators so Im hopeing that will help with hte output.

What did you do with the existing rectifier bridge?

SMALL LOAD VS LARGER LOAD
You said I should use a small load of bulbs...you said I could damage the PMA if I put too big a load on it?

Wire can only handle so much current before it gets hot. You said you rewound the alternator, using what gauge wire?

But will that make a difference any? Because if I go to small wont the energy need to go somewhere, and if its too small, then I will need some sort of dump load to divert it otherwise where will it go....
wont that damage the PMA more because theres too much energy bouncing around in a limited circuit without an escape.....
Or will it simply push the electrons out faster to create an even stronger bulb shine?
VS
If I use more than enough bulbs stacked wont that actually keep pushing the electrons and if I set them in parallel it will be like a glass of water that never really gets quite full to capacity...so I wont burn anything out - versus if I go too small wont that be like a cup I overfill with water?

Assuming you actually can get enough power out of the alternator, worst case, yes, you'd blow some bulbs. You need to find a way to regulate the output voltage - as in the speed of rotation. On a small turbine this is sometimes done by a hinged tail vane that will aim the turbine slightly out of the wind. Bigger units regulate the rotor current, like in a car.

Also consider, a heavier load requires more energy to spin the alternator. Just like riding your bike up a hill.

HOW THE ALTERNATOR IS WIRED...
Simply have 3 phases of coils coming out of the alternator. 3 wires, and I thought I needed a rectifier..but perhaps I dont.
But I saw a video where this one guy rectified the A/C to carry his current with an extension cord..so thats what I am going to try to do.
Is this wrong?

No, not wrong. You can run dc, the bulbs don't care.

HSStudent, alternators need to spin, fast. Are you connecting the turbine directly to the rotor? I'm not sure how you rewound this but in a car, at idle, they are usually spinning at least twice as fast as the engine so say 1400 rpm, at idle. As for power output, you can probably figure about 500 watts per horsepower with losses. FYI, that's about what a typical portable gas powered generator makes for power.

 

[hsstudent]

thanks

Thanks for the response A&PDan

I like the way you broke it all down.

I didnt rewind anything I just made a separate stator and a separate rotor with my own magnets I put them in 3 phases and i used a rectifier I bought online. I basically gutted the old stuff that was inside the casing.

Can we go one by one...
Right now my most important concern is "The Load"

Im scared Im going to either start a fire or damage the PMA so Im thinking if I try to create a giant pitcher(lightbulbs in parallel) that pitcher is goign to be more than I will generate, than all that will happen is maybe some bulbs wont get lit up -- but are you saying the load dictates how fast the generator needs to spin so it will spin harder if it has more load to carry?
which kinda means the more load I have, overall bulbs in parallel will reflect the torque needed turn the rotor?

I dont grap that concept much -- it confuses me because the blades or the generator dont know in advance how much load they have (do they?) because it just generates power and pushes the current through the voltage...so how will the PMA know that. Or is their some sort of natural resistance that the load creates on the generator that dictates some type of affect on the generator with regards to torque

Perhaps making this simpler..can I ask these 2 questions..

if I were to take 10 lightbulbs (1000 Watts) and somehow generate 1500 watts what would happen?

If I was to have 10 lightbulbs, but only generate enough to cover 5 lightbulbs..what would happen?

Thanks again..you are being really helpful

 

[AandPDan]

Im scared Im going to either start a fire or damage the PMA so Im thinking if I try to create a giant pitcher(lightbulbs in parallel) that pitcher is goign to be more than I will generate, than all that will happen is maybe some bulbs wont get lit up -- but are you saying the load dictates how fast the generator needs to spin so it will spin harder if it has more load to carry?

It's unlikely you'll start a fire. I doubt you'd damage the alternator.

which kinda means the more load I have, overall bulbs in parallel will reflect the torque needed turn the rotor?

YES! Remember, energy can't be created nor destroyed. It can change form though. You'll be taking mechanical energy, from the rotating shaft, and turning it into electrical energy. The more load (resistance) on the circuit the more torque required to spin the alternator.

I dont grap that concept much -- it confuses me because the blades or the generator dont know in advance how much load they have (do they?) because it just generates power and pushes the current through the voltage...so how will the PMA know that. Or is their some sort of natural resistance that the load creates on the generator that dictates some type of affect on the generator with regards to torque

Again, there is a resistance, the lights are the resistance. No, the blades don't know how much load they have. They just won't spin as fast, or at all, with a heavy load. It's that simple. Less load = faster RPM. More load = slower RPM --- if the load stays constant.

Perhaps making this simpler..can I ask these 2 questions..

if I were to take 10 lightbulbs (1000 Watts) and somehow generate 1500 watts what would happen?

If I was to have 10 lightbulbs, but only generate enough to cover 5 lightbulbs..what would happen?

Some math:

I=E/R. Current (I) = Volts (E) divided by Resistance (R).

P=IE. Power (watts) = Current (amps) times voltage (volts). So, mathematically you can also say that E=P/I.

The resistance of a 100 watt bulb, 120 volt, is about 144 ohms. It's fixed, you can't change that value. Current (I) is a relationship between volts and resistance. If you increase volts, so does the current. The bulbs get brighter. As both volts and current increase, so does the power (watts).

If you were to generate 1500 watts the voltage would have to go up, above 120 volts, using your typical bulb. The ONLY way you can control that is by increasing the current required (adding more bulbs) OR by slowing down the alternator.

 

[hsstudent]

windmill hs student

Thanks again great answers...

Can I present two scenarios that if you answer them I think I would be able to grasp it all.

What is the actual cause/affect process that would happen .. between the PMA and the parallel lightbulbs and the energy produced if.....

#1
if I had a load of (10) 100 watt bulbs (1000 kw) and I produced 1500 watts (or even more) through that parallel of lightbulbs?
What would happen here?

Would the energy overflow in some way?
And what would the result be (blown bulbs, etc)
Or would the PMA (without a regulator) just stop producing power to compensate and just freewheel?
I dont have any regulating device whatsoever connected to the PMA
But what would happen?

#2
If I had (10) 100 watt bulbs and I produced only 500 watts (needing 1000 watts) through that parallel of lightbulbs.
what would happen in that scenario?

would I not power some of the light bulbs?
Will all of the lightbulbs not power up?
Would they shine the same, trying to equally distribute the current among the parallel?
Or would the first in the parallel shine brighter than the others?
Or because there is not enough to go around will nothing shine?

If you could describe in as much detail as possible what would happen in those 2 scenarios I think that would pretty much help me understand it all.

Thanks again for taking the time to help out.

 

[mpoulton]

I didnt rewind anything I just made a separate stator and a separate rotor with my own magnets I put them in 3 phases and i used a rectifier I bought online. I basically gutted the old stuff that was inside the casing.

So this is now a permanent magnet generator. How did you design the rotor and stator? How did you fabricate them? If you designed them using actual engineering calculations, then you should already know what voltage and current to expect at what RPM and torque values. If you didn't design it using real math and engineering... then I strongly suspect you won't get a usable output. You'll get something, but you won't be blowing any 100W light bulbs. Engineering electromagnetic devices is complicated and difficult, and lots of little details (like the rotor-stator gap) matter much more than you would expect. You really just need to spin the thing and measure the voltage, then start adding a load and see what happens.

 

[hsstudent]

Its always been a PMA -- that never changed. Look at the title of my posting

MPOULTON -- thats what Im ready to do but my concerns are I dont want to damage anything or create a fire of some sort.

So again, can you answer my previous question with its two scenarios as to what would happen if I dont have enough power,
and what would happen if I have too much power..

Please read my previous post for the details of that.

Lastly, Im scared of current and eletricuting myself, but are you saying I could simply measure the ends of the PMA with no load on it with my Multimeter while its spinning and the multimeter wont burn up/blow up because it will complete a circuit if I create too much energy?

If I can do that then that kinda would help me greatly.
My uncle eletricuted himself really bad so Im kinda scared to do certain things..

But I would still like to know what happens when I have too much power, or if I dont have enough power.

Can you help again
Thansk for answering the first post

 

[AandPDan]

HSstudent,

For now, don't focus on the watts. Just see if you get some volts out of the thing and how many, then focus on testing it.

Yes, just put a meter on it and let it run. I can't say what the voltage will be as it all depends on your design. Don't touch any of the leads as you test it and you'll be OK.

One you find out the voltage we're talking, then we can start figuring out how to test it with a load.

No, the PMA won't freewheel. The energy won't "overflow." The faster the PMA rotates the more voltage you'll get out of it.

 

[hsstudent]

thanks everyone...but can someone please tell me what the result would be to the above 2 scenarios I painted before I start testing

This will help ME with understanding everything as I proceed.
Otherwise its people who know more than I do wanting me to understand at their pace, not my own. Im a kid, learning as I go
And it will ease my mind about the potential hazards of the power Im going to create...

So please....

Can someone tell me what would be the cause effect of the 2 different scenarios please and thank you.


#1
if I had a load of (10) 100 watt bulbs (1000 kw) and I produced 1500 watts (or even more) through that parallel of lightbulbs?
What would happen here?

Would the energy overflow in some way?
And what would the result be (blown bulbs, etc)
Or would the PMA (without a regulator) just stop producing power to compensate and just freewheel?
I dont have any regulating device whatsoever connected to the PMA
But what would happen?

#2
If I had (10) 100 watt bulbs and I produced only 500 watts (needing 1000 watts) through that parallel of lightbulbs.
what would happen in that scenario?

would I not power some of the light bulbs?
Will all of the lightbulbs not power up?
Would they shine the same, trying to equally distribute the current among the parallel?
Or would the first in the parallel shine brighter than the others?
Or because there is not enough to go around will nothing shine?

Thanks again to you guys that have helped me.
Theres much I dont grasp...and before I start I need to understand this concept of over and under powering so I can proceed comfortably.
Thats just the way I pick up things

 

[curiousB]

what would happen if I dont have enough power,



and what would happen if I have too much power..

If you don’t not have enough electrical load on the output of the PMA the turbine will spin faster. You see energy is conserved so the mechanical energy available to the turbine will either convert to electrical energy via the PMA or be converted to kinetic energy in the speed of the turbine. Most commercial wind turbines have mechanical brakes for this very reason. In an intense wind storm they can lock down the turbines so they don’t go above safe RPM speeds. Some energy will be lost as heat through all the points of friction where higher speed will increase the losses.
A higher RPM will drive up the output voltage as well since you do not have a voltage regulator in this scheme. So this could get potentially dangerous.

The flip side is less worrisome. If you put too much load on the electrical side the turbine will be just bogged down and not spin much. I think this is your more likely case. You are talking 600W to 700W of load which will require 1-1.5 HP of mechanical energy in. That is if you PMA is well designed and optimized which seems unlikely (an auto alternator might have 20-30 man years of engineering design into it). So I suspect your PMA won’t be that efficient. Let’s say 10% for arguments sake. So to sustain a 600W load you'll need 6000W of mechanical energy or 8HP. That better be a good sized turbine to generate 8HP.

 

[AandPDan]

In both scenario's all the bulbs will be the same brightness when wired in parallel. They all have the same voltage and current flow.

The bulbs are only rated at 100 watts. Any more and yes, they'll burn out.

To low a voltageand they may not light up at all.

 

[Evstarr]

I don't think the two scenarios you posted can be answered as asked because there are 2 missing variables for the equation. The bulbs you want to use are designed to output a particular brightness at 120 volts ac.
We dont have any way of knowing what your output voltage will be so it's impossible to answer.
What you have been told is that if you wire 10. 100w light bulbs in parallel, they will all illuminate to the same level (or fail to illuminate) provided they are all identical.

If you produce sufficient power at whatever voltage, they will illuminate to some extent. If you manage to produce excess power, some or all will burn out. Due to vagaries in manufacturing, some will be more tolerant than others of the overload condition.

One of the other posters asked you what size wire the windings are on your generator because they could become the weak link in your circuit and burn thru in the event that this device produces significant energy.

Congrats in getting this far and I eagerly await the test results when you fire it up!!
How old are you btw?