Resitance under load

Anything about construction that doesn't fit into any of the above

Resitance under load

Postby pdm on Thu Aug 30, 2007 1:30 pm


I builded the same turbine as per your instructions, i was thinking to buy
yours but then only for 2 days i made the same replica as yours and its
working ok.. i get the same maximum voltage of 58 volts.

but it appears that the power i use to rotate it is not enough and when
there is no electriacal load the turbine rotates at 250-300rpm easily and
the voltmeter shows 40-58 volts easily.

The problem is when i put for example 5 wats/12v bulb then the whole system
stops and its VERY VERY VERY hard to rotate the rotor anymore, and then the
voltage drops to 6-7 volts and the bulb works but the rotor is very veyr
hard to rotate? is this normal? do you experience the same ? Do you tihnk i
have made something wrong? is it normal that the rotor gets more resistance
as more load is added?

If you can answer this questions you will help me a lot.
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Joined: Thu Aug 30, 2007 1:25 pm

Re: Resitance under load

Postby windgat on Thu Aug 30, 2007 1:40 pm

Hello. Firstly well done for building it so quickly!

When you draw power it will get harder to rotate - thats what I was referring to in my email to you about equal and opposite. When you draw electrical power the energy has to come from somewhere.

Are you sure that it is a 5W bulb? That is very small - perhaps it is 50W? If I short out my generator it gets very hard to turn, but 5W shouldn't do that. I am also not sure what you mean by 'very hard'... Are you driving it directly, or are you gearing it up somehow?

Have you seen the new data on the benchtests page?
Perhaps that will give you something to compare to.

If you clear up the above questions I can answer in more detail.
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Location: Cape Town, South Africa

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