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Forum Index : Windmills : chinese 300 watt electronic brake error

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rgormley
Senior Member

Joined: 22/02/2006
Location: Australia
Posts: 245

Posted: 10:05am 06 Dec 2009

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I had noticed my 300 watt 24v cheap chinese mill (jcar)

has started to hit the electronic brake to early like at 22volts. was around 28 when new. hence it now wont charge my 24v bank.

i have pulled the thing to bits and cleaned all connectors, carbons to yaw are clean. all looks ok inside.

the electronic brake thingo is a black magic sealed unit 3 AC in 2 DC out in a aluminium case heatsink bolted to the back of the genny with thermal compound.

the unit has never seen extended use of high current.
maybe a burst of 20 amps or so for a few secs but mostly around 2-5 amps

the 3 ac wires happily measure equal ac voltage across them when i cranked it by hand (and shorting any of the 3 AC wires makes it brake.

my next step is to piss of the electronic brake/reg unit and run the 3 ac wires to two rec bridges and then DC down the yaw brushes. we dont see much high winds for the batts to over charge.

or any ideas??

GWatPE

Senior Member

Joined: 01/09/2006
Location: Australia
Posts: 2127

Posted: 01:45pm 06 Dec 2009

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Hi Richard,

sounds like the mill has been run without a load. I have one of those chinese potted black box regulators. Mine was on my now defunct F&P mill. Mine survived the 600W peaks during storms. Still works at 29.5V, like when first used. I placed a 2000uF 35V cap directly across the outputs, to help protect the unit during my testing. Has survived load disconnection this way.

The potted units are not easily repaired.

Gordon.

become more energy aware

Downwind

Guru

Joined: 09/09/2009
Location: Australia
Posts: 2333

Posted: 03:16pm 06 Dec 2009

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Just a thought.
Have you checked for a bad wire connection some where between the mill and batteries causing some resistance as this will allow the mill black box to see a higher voltage than the actual battery voltage and cause it to hit the brakes early.
The 22 volts you quote i gather is the voltage at the batterys.
Can you test the voltage closer to the mill and see if there is a difference.

The other option might be to add a resistor in series to the voltage sense wire going to the black box so as to fool it to hit the brakes a little later.

I would check my cable and battery terminal connections etc first.

Pete.

Sometimes it just works

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