stator tempature with mppt control

[halfcrazy]

Ok if a stator in the 10 ft machine is good for 1000 watts what happens if you hook the turbine up to a mppt controller and you get say 1800 watts is the stator safe? my understanding is the heat is caused by the batteries holding the stator voltage down?

[wdyasq]

What brand and model number MPPT controller do you propose to use for this exercise?

Ron

[halfcrazy]

well as Robin previusly stated i will eventually get the chance to try the new Classic on my turbine just doing a little pre test investigating

[electronbaby]

The heat is caused by resistance losses in the stator.

If the MPPT controller allows the stator voltage to climb, then you are effectively removing the heat dissipation from the stator. You will never remove all of it, but you remove quite a bit by using power point tracking. This means that the stator is capable of producing more power, more efficiently.

Try running the Ohms Law calculations for your machine, but plug in a higher voltage and see what happens.

[TomW]

Roy;

Yeah, its something to do with eyes, squares and R's.

Its easy to "miss" that Ohm and Watt and their laws apply to sources as well as loads.

Tom

[oztules]

The stator is really only interested in the current.

If you wish to simulate high power mppt effects (while you wait for it to turn up), just use double the battery voltage and watch what happens.... huge increase in power out, no negative stator effects.

The downside will be that you have to live with it... it will behave as a very different animal. If you are used to "stall limited operation", then this will be an education.

I tried 4m mill 48v (nominal 30 amp stator) on 12v, 24v, 36v, 48v, 60v,78v,96v.

On a 12v battery bank... about40-60watts, on 24v bank, about 200-250w, on the 48v bank about 1.2 - 1.8kw, on 96v bank about 3-4kw, on resistance load only (4ohms) over 5kw@140 odd volts

Same stator, same blades, same furl. No stator damage.... just shattered nerves at 5kw.

.........oztules

[oztules]

I see you have yet another thread on this .. the controller has already arrived... so you will not have to simulate I guess.

..........oztules

[electronbaby]

yes, I should have been more clear regarding current. The resistance does not change much, so the only other variables that are of importance in the grand scheme of things, are voltage and current. Say you had a 48v battery system and you used mppt to allow your stator voltage to rise 4x greater (192v). This will cut down your heat dissipation exponentially, BUT you have to wind for this voltage to begin with, and up until this point, mppt has not been readily available unless you wanted to design your own...(no warranty) haha, so there haven't been many others that have played with this except the people that have grid tied.