50/60 Hertz Tuning

[Draco Rylos]

How many coils and how many turns would be required to make a Axial Flux Permanent Magnet generator that would put out a fair voltage and current @ 50 or 60 Hz, dependent on where in the world the person building the wind turbine generator is located? The thing about using a inverter and batteries is there are more points of failure in a system using those components compared to a system that does not use those components. I'm just asking around right now, but I just want to know if I ever do start working on building a AFPM Wind Turbine generator.

[nickle989]

The method I use is to make a 3 phase unit PMG.  Run this into a couple of 25 amp rectifiers (the little square jobs with some heat sinks).  Put it right to a couple of 12 volt batteries ... they will act as capacitors, a regulator and a storage unit.  Then just hook up an invertor.  The lowest cost yet.  If you are worried about over charging the batteries you can hook in a circuit to a 25 watt bulb.  This will work very well for a turbine with up to a 12 foot swept area.

I can also tell you do not expoxy your coils in because they will over heat crack and then you will have pile of crap.  better to use a high temp rubber spray or bake them in the oven with some enamel.  Then just use some plastic wire clips that use screws to hold them down.  You will provide some cooling and coils will last a much longer time.

Not to provide a plug but you can check out bluewindpower dot com a couple hundread ... and get one that is tuned for your wind area, this will allow you to concentrate on your blade design which is far more important.

[Draco Rylos]

@Nickle989 I am trying to stat AWAY from the battery and inverter method of storing power because that method has higher number of points of failure. Rectifier Diodes could fail. Something could happen with one of the batteries, and with a inverter, you have too many points for failure. I know there are so many areas within the inverter that are stressed more than others and could blow out or fail in some way.

[nickle989]

I understand what you are saying ... maintaining a frequency on a wind system is very problimatic as wind is not contstant ... whether this be AC or DC generator.  Large turbine system have very large switch gear at the base of the towers and complex software to control it with the gear hubs. 

Do you have constant wind where you are?  What height are you going to place the tower?  Are you connecting to the power grid?  What do you want to use the power for?  The solution is not an easy one to accomplish and if something does go wrong anything connected to the turbine in the way of electrics or electronics will be fried as there is no way to predict wind gust loads which produce the spikes in the system.

[mscoffman]

Dracos,

There was series of graphs showing the energy "problem" in the US.
One was the average wind energy available for several years. What
one saw is that the average is quite low maybe 10% but on certain days
it was goes much higher. This doesn't corespond well at all, to the full
demand orientation of how consumers expect to use electricity. Now, the
power companies can make use what ever energy is available because
they can throttle their steam plants rapidly and make good use of
the times when the wind energy is very high. An individual generator
though is more problematic and one really will wish they had a backing
store for electricity of somekind to even-out the demand. Another thing
that can help out large generators is that they can have automatic
mechanical transmissions.

The tricky part of 50/60HZ is that you need that so many magnetic
poles per second (50 or 60) which in a normal generator design
would be a constant and directly dependent and proportional to
RPM.

It may be possible to do microcontrol computer controlled magnetic
pole switching which would let one synthesize approximate waveforms
by dynamically changing generator coil connections.

But having insufficient net power for instantanious demand is still
a problem. You would in any case required to have a variable
autotransformer to keep the voltage adjusted because that needs
to be relatively constant too and some way to "burn" extra power
when the wind is producing too much.

All these factors are deterministic though ,and one could write a
relatively simply computer simulation to see what one could expect
in terms of power then feed in some average wind data and demand
data.
   
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D.C. voltage inverters are becoming more robust and less expensive,
and one can get warantee replacements of the inverter. These type
inverters and backing stores are probably going to become standard
equipment in many alternate energy applications in the future. So
getting one correct, would most likely not be wasted time.

:S:MarkSCoffman