Hero999

That's a good idea!

A centrifugal governer system could be used to pull the magnets out of the coils as it spins faster.

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simoin

okay so these are all great idea's but the original questions remains, does anyone know how to setup a star/delta controller that is user adjustable so that the optimum change over point can be found after achieving and holding optimum point for x seconds?

see the picture below for what the magnet block looks like.



Please have a browse around of this website to see exactly what it i am doing... www.thebackshed.com

Thanks for the help thus far

Nigel Goodwin

It's easy to do, either using a micro-controller or just opamps etc. Simply measure the speed of the rotation, if it's below a certain level then select it as a high voltage connection, if it's above a certain level then select it as high current. Without a micro a simple frequency to voltage conveter feeding a comparator should be all you need?.

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simoin

so is the sort of op-amp you are referring too? http://en.wikipedia.org/wiki/Operational_amplifier

How would you suggest measuring the speed of shaft rotation?

Nigel Goodwin

Yes, used as a comparator, or you could use a specific comparator chip?.

There's a frequency to voltage IC you can get (I can't remember the number off hand, but someone will probably post it shortly?) - or you can use a 555 in monostable mode.

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rippersoftware

Scoraig measures based on the rise of voltage from the AC generated from the 3 phases. Captures this and runs it thru a tachometer circuit.

From there, you can do what you want with the analog information. Scoraig switches heaters onto the output for load based on RPM. See the page:

http://www.scoraigwind.com/circuits/index.htm

RipperSoftware

Hero999

Thank you and welcome to the forum.

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jolino

Hi Simon,

Considering all what people said, let me suggest one more simple solution in contrast with the circuit that you have posted in first place, and again, considering some cited aspects.

1. The rotation sensing is maded by viewing the wave/signal present in any point of any coil, before rectifiers. No more hall-efect sensor needed.
To make this work, the generator/battery disconnection must be made beetwen the bridge and battery.

2. I suggest 2 relays intead of one by two reasons:
a) When STAR relay is OFF -> STAR position, no battery discharge.
b) When ON / OFF relay is OFF -> generator is desconnected from bat and no bat consumption.
- So, when both relays off, just a few miliamps from battery.

3. With the KEY, you can configure:
a) The speed at wich the system switch from star to delta.
b) The speed at wich the system disconnect the generator.
c) If needed, you can have generator disconections to max and min speed.

4. You have also STAR/DELTA indication througt the Leds.

Notes:
1. Of course you need a little 78L05(+5V) to supply the PIC.
2. The software to do it, is very easy.
3. Sorry for duplicated references in the schematic.

Regards
Jolino

Attached Images

sdswitch.jpg (27.3 KB, 21 views)

simoin

anybody else have any thoughts on the new circuit jolino ha put forward, it sounds as if it will be great. I think i can work out a 5volt power supply for it easy enough too.

Klaus

It appears that many respondends jumped on the bandwagon without bothering to read the links you posted, where it becomes obvious that there is NO field current to adjust with a permanent magnet rotor.
So you are right to ponder the star/delta question.
Nigel's reply gives you a good reason why bothering with that complication.
My practical suggestion is how to accomplish this:
Do the switching bit with a suitable relay.
Control the relay from a centrifugal switch.
You may salvage such a switch from any single pole squirrel cage AC motor, aka ex washing machine (not Fisher Paykel;-).
You may have to tinker with the centrifugal weigths to get the right switching time. To do this rig up the wind generator minus the blades and drive it from a suitable variable RPM source - if I had to do this I would use my lathe for the driving power.
The electronic 32 point switching module seems far too complicated for this application and I can't see why anybody would require so many switching points unless you plan to use variable geometry adjustable blades for your windmill.
Klaus