Alternator

[keller36]

Hi, I'm Kyle,

 

Here is my question; I have built a small alternator (as a hobby science project) which can generate enough electricity to cause pain when in contact with the terminals, yet not even a 1.5 volt flashlight bulb will light when connected. The alternator has four magnets on the rotor (alternating and placed at 90 degrees apart from each other) and four coils on the stator which at every 1/4 of a turn all four coils and magnets are lined up. I am only powering it with a power drill for now before connecting it to my 5hp engine. I also placed a 120v to 2000v microwave high voltage transformer on it, which leads me to believe that maybe there's just not enough amps to light the bulb, but I don't really know for sure. Thanks in advance for any answers.

[Danijel Gorupec]

Sure, it seems certain that you have high-voltage, small amps. The high-voltage transformer creates the high voltage (but transformers do not generate power). You may try without it (I would).

 

If you have a voltmeter, you can check your output voltage without anything connected. And then you can check how much the voltage drops when you connect the light bulb. You will see that voltage drops a lot.

 

Note that if you use lots of thin-wire turns in your generator - you will generate high voltage, but small amps. On the other hand, if you use smaller number of thick-wire turns, you will generate low voltage, higher amps. The power is proportional to amp-voltage product. It is hard to say, but I beleive that you should work on stronger magnetic flux in your alternator - do you use strong magnets, do you use lots of iron on your magnetic path, do you have small enought space gaps between iron/magnet parts?

[keller36]

Sure, it seems certain that you have high-voltage, small amps. The high-voltage transformer creates the high voltage (but transformers do not generate power). You may try without it (I would).

 

If you have a voltmeter, you can check your output voltage without anything connected. And then you can check how much the voltage drops when you connect the light bulb. You will see that voltage drops a lot.

 

Note that if you use lots of thin-wire turns in your generator - you will generate high voltage, but small amps. On the other hand, if you use smaller number of thick-wire turns, you will generate low voltage, higher amps. The power is proportional to amp-voltage product. It is hard to say, but I beleive that you should work on stronger magnetic flux in your alternator - do you use strong magnets, do you use lots of iron on your magnetic path, do you have small enought space gaps between iron/magnet parts?

 

The bulb won't light without the transformer either. My coils are a fair amount of thick wire (from another high voltage transformer, the coils where the low voltage enters) and the magnets I used are from the magnetrons out of two old microwave ovens (the strongest magnets I've ever handled). There's about 1/8 to 1/4 of an inch between the magnets and coils when they are closest together - but, my alternator has no iron cores on the coils - which I don't know if that makes a difference, or not.

[Danijel Gorupec]

1/8 inch still seems quite a lot (sorry). Do your best to reduce... You absolutely must have iron wherever the magnetic flux goes. Only small gaps are tolerable. (The iron is a highway for magnetic flux).

 

You are happy becuase you can now optimize your alternator - you will learn a lot. First, I believe, you need to understand the exact magnetic flux path in your alternator so you can make it stronger.

 

 

[otivaeey]

The bulb won't light without the transformer either. My coils are a fair amount of thick wire (from another high voltage transformer, the coils where the low voltage enters) and the magnets I used are from the magnetrons out of two old microwave ovens (the strongest magnets I've ever handled). There's about 1/8 to 1/4 of an inch between the magnets and coils when they are closest together - but, my alternator has no iron cores on the coils - which I don't know if that makes a difference, or not.

 

What? no iron cores, that is very very crucial to magnetism. You got to have magnetic cores so that a strong magnetic flux can be lead out.

[TonyMcC]

I was just wondering - I suppose you have the coils joined so that they all work together when under the influence of the changing magnetic fields. i.e. produce voltages that are in phase. If not then one or two of your coils could be reducing output. This does not seem likely as you seem to be generating a large voltage from a high resistance source (your generator).

[Pantaz]

It would be helpful to see a simple diagram of how it is constructed. (Electrical and mechanical.)