Aerogen 2 / LVM 212 Dump Load Resistor Value

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SteveNotlob

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I have an Aerogen 2 / LVM212 Wind Generator and 2SB regulator but don't have the dump resistor.
Does anyone know the values of the resistance / wattage required as I cannot find anything on the 'net, just references to a dump resistor but no values.

Thanks
 
SteveNotlob said:
I have an Aerogen 2 / LVM212 Wind Generator and 2SB regulator but don't have the dump resistor.
Does anyone know the values of the resistance / wattage required as I cannot find anything on the 'net, just references to a dump resistor but no values.

Thanks
Click to expand...

Unless anyone can answer the question why not calculate a resistance value.

Aerogen 2 is I believe 48 watts ( call it 50) Assume the regulator controls at 14.4 volts

R = V2/W. I make that 4.14 ohms

you must allow for the full rated power output to be dissipated, ie at least 50 watts
 
Would a resistance so low effectively act as a 'brake'? I see that shorting the output via a switch causes the blades to stop! I would imagine that cabling and switch would be around the 1 ohm mark. Or am i missing something here?
 
Bit of a ramble this.
I don't have a scintilla of electrical knowledge so I don't know if this is any use to you:

https://www.sv-zanshin.com/r/manuals/lvmregulatorselectionguide.pdf

My Aerogen 25 (which may be the earlier version of yours) is connected to a lump of electrical gadget called a shunt regulator. Part number 94-972-79, this bears no relation to the numbers in the document but there we are. It is connected across the battery terminals. It has never even felt vaguely warm so:
Maybe it has never worked
Maybe I connected it wrong
Maybe the fan has never worked up enough fug to make it work

Whatever, the battery has never boiled and has always been kept up.

The heat sink has two distinct components in the middle which may be the schottky blocking diodes mentioned above. Any way FWIW there we are. The Aerogen is a great piece of kit.
 
VicS said:
Unless anyone can answer the question why not calculate a resistance value.

Aerogen 2 is I believe 48 watts ( call it 50) Assume the regulator controls at 14.4 volts

R = V2/W. I make that 4.14 ohms

you must allow for the full rated power output to be dissipated, ie at least 50 watts
Click to expand...

I have just come across a generic wind turbine dump load info page and you are correct with your theory. It suggest a 3.9 Ohm at 50W or greater.
Many Thanks.
 
SteveNotlob said:
Would a resistance so low effectively act as a 'brake'? I see that shorting the output via a switch causes the blades to stop! I would imagine that cabling and switch would be around the 1 ohm mark. Or am i missing something here?
Click to expand...

I think not. It will allow the generator to continue generating its full output which is then dumped by the regulator.

Shorting the generator, but note how that must be done with a double pole switch, will act as a brake Note also that once braked in this way the blades must be secured with a rope.

The resistance of the switch and wiring should be way less than 1 ohm ......... less than 0.1 ohm more like
 
VicS said:
I think not. It will allow the generator to continue generating its full output which is then dumped by the regulator.

Shorting the generator, but note how that must be done with a double pole switch, will act as a brake Note also that once braked in this way the blades must be secured with a rope.

The resistance of the switch and wiring should be way less than 1 ohm ......... less than 0.1 ohm more like
Click to expand...

Single pole on/off switch works OK, ours has been like that for years.
 
Graham376 said:
Single pole on/off switch works OK, ours has been like that for years.
Click to expand...

I was quoting the installation instructions which specify a double pole switch.

Looking at the wiring diagram however I can see that both poles are wired in parallel. Presumably this is to share the current between the two. Maybe not important with the Aerogen 2 but more so with the larger models.

I wonder why they did not suggest a meatier switch ...... a small battery isolation switch maybe ?
 
I have a D400 wind turbine from Eclectic Energy, so 400 watts when it’s blowing old boots. It has 2 dump resistors wired in parallel which become active at 13.7 volts. Each resistor is 0.68 ohms, so combined gives 0.34 ohms. I couldn’t measure such small values with my meter on its lowest range of 200 ohms.
There is braking switch in the circuit which Is DPDT. I do have to tether the turbine if the braking switch is used.
 
Last edited:
VicS said:
I was quoting the installation instructions which specify a double pole switch.

Looking at the wiring diagram however I can see that both poles are wired in parallel. Presumably this is to share the current between the two. Maybe not important with the Aerogen 2 but more so with the larger models.

I wonder why they did not suggest a meatier switch ...... a small battery isolation switch maybe ?
Click to expand...

Ours is/was (I've just removed it) an Aerogen 4 and the 10amp on/off switch was wired across the + & - feed between generator and regulator. Switched off every night due to vibration through the gantry. Only time the blades were tied up was when leaving the boat for extended periods or very high winds. With it shorted, generator turns a lot slower and no sign of wires heating.
 
Graham376 said:
Ours is/was (I've just removed it) an Aerogen 4 and the 10amp on/off switch was wired across the + & - feed between generator and regulator. Switched off every night due to vibration through the gantry. Only time the blades were tied up was when leaving the boat for extended periods or very high winds. With it shorted, generator turns a lot slower and no sign of wires heating.
Click to expand...

A 2 pole 20 amp switch is specified. It is also recommended that the blades should be tied off once braked electrically.
 
Graham376 said:
Why bother with 2 pole when it's just shorting two wires together? Anyway, it was fine for 15 years or so as it was.
Click to expand...

I imagine in order to divide the current between two pairs of contacts so that a simple toggle switch can be used but able to handle a current in excess of the max rating for one set of contacts. I have no idea what the current might be when first braked in a high wind strength. The performance data only relates to generating at 12 volts.

Also just noticed that a double pole double throw , centre off switch is specified ( Ie ON, OFF, ON ) but as far as I can see that would only be necessary to prevent shorting the battery when using without a regulator or with a single battery regulator, but not with the double battery regulator which has blocking diodes in the output connections and must be used when other charging devices eg an alternator is are present.
 
Graham376 said:
Why bother with 2 pole when it's just shorting two wires together? Anyway, it was fine for 15 years or so as it was.
Click to expand...

I am using a regular 20 A automotive relay with the common connected to the positive output from the gen and switching over between the battery and earth. The fast action of the relay is good for handling the initial 1 second or so of high power when the brake is applied. From the moment they slow down the power being wasted on the braking circuit is so small, any worries about overheating it are absolutely unfounded. The trick is, the (almost) stopped blades are aerodynamically stalled so they are not able to produce any appreciable amount of energy. While there will be some current, the voltage on the shorted circuit is close to zero so the power will be in 1 digit figures. The breaking circuit doesn't need to be able to handle the full power of the generator and in fact, the smaller resistance the better. The stalled blades produce very small torque and need close to zero mechanical resistance to reach the speed at which they become efficient. With the coils shorted, the mechanical resistance will be high enough to prevent them getting even close that point. Tethering them is not necessary. I've been using this system for about 5 years and it has survived a few gales without any problems.
 
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