Dump Load

[esteban.vandam]

Hey everyone!

I would need a little advice regarding the dump load that you use for the 2400mm Piggott machine: what value of resistance do you use? Any materials in particular (eg: chrome-nickel)? How would that change if the tail is made a little heavier and the generator reaches an actual output of 1000W (instead of 700W). Thanks! Esteban

[Noam Dotan]

Hello Esteban.

It depends on your dump load controller and the maximum current you expect from your turbine. If for instance you use the Morningstar 45 A and in any case you do not run more than 40A in your generator (I strongly suggest to design the furling for maximum average of 35A, otherwise you will burn your generator in wind gusts. If you want more power build a bugger turbine!) So if max current is 40A and you have 700W power: R=700/(40*40)=0.44 ohm. We used to make the standard high power resistor. It cost fortune. A simple robust idea that we once tried is to use a fence wire stretched between two wood sticks. The length depends on the type of galvanized wire you use. but it is easy to measure. If it is in the open it cools quickly and in any case since it is long it does not get really hot.

Hope it helps.

what about your furling work? any written document?

Bye

[Jay Hudnall]

We use a ceramic breaking resistor from ECOMSA in spain.  0,7ohms 1500W rated power.   28,5V / 0,7 ohms = 41 A.     41A * 28,5V = 1170W

Do you try to run the 2m40 machine at 1000W on purpose?  Or is the tail just too heavy?


A+

Jay

[Hans Peter Duesentrieb]

Hello,

for the 2F 400 W windturbine we usally use high-power 50 W resistors. they are available with many different resistance and cost between 3 - 6 €.
you can then solder them together to the resistance you need to get the current-flow you need to dump the entire power of the windturbine.

but you also have to check weather every single resistor doesn´t dump more power then it is made for.

here is the link. the enire dumpload for a 400 W turbine cost around 30€. for 1000 W the cost would be around 80€.

you can also buy one of these plug and play high-power resistors with 1 Ohm. but it would just dump I_dump = 28.5V/1 ohms = 28,5 A; so the power would be P_dump = 28,5 A * 28,5 V = 812,25 W

since you said you are running it at 1000 W you could check whether they offer these once with lower resistance.

i would also be interested whether you are running the 2.4m turbine  on purpose at 1000 W?

cheers from berlin

immanuel

[dan Bartmann]

It's a bit off topic but... lately I have been using the controller described here:  http://www.windsine.org/

If you don't need the heat for the resistors for anything, it works brilliantly ~ especially if the system also involves PV.

In short, it will stop the turbine at a set voltage for a set period of time *unless* a low set voltage is reached.  Say the battery is full up, I might set it to shut down at 58V and come back on if two things are true, and hour passes,  and voltage has dropped to 54 ~or if batteries drop to 52 (maybe a large load got turned on), turn on immediately.

It will also shut down if it sees a phase imbalance. (stator problem, broken line, or bad rectifier) ~and it won't come back on until the controller is reset.

It could also shut down based on wind speed or frequency ~ for a set period of time.

It saves wear and tear and provides some addition protection for the turbine.

[Esteban van Dam]

Hey, this is interesting! I guess you lose some energy, compared to the typical system. Do you have a rough idea of how much, in %?

Cheers

Esteban

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