Truck alt Pics & Info

[Matt Au]

Hi All,

I think when i put more pics up on the last post, it deleted the others for some reason, will post them again.

Yes I nearly allways use furling on my turbines, similiar setup to most gravity systems I see here, but i don`t off-set the yaw shaft as much and also the angle of the tail pivot is at about 10 degrees sideways and 10 degrees back.

I tried to copy the Westwind turbine setup, made here in Australia.

It seems to work well once you adjust a few things, but they can go into Kamakazi mode at certain wind speeds as Hugh Piggot call`s it, this rarely happens but is scary when it does.

Will be building a larger 50 Amp converted 24V truck alt turbine soon and will get some Pics together of the different stages of production.

I will be using a larger blade rotor maybe 1.7M.

? I have got hold of some very cheap 100mm/25mm/9mm Neo Magnets which i intend to cut into 3 pieces being 33mm long, and use these for my next alt.

Does any one know how to cut these magnets without getting them hot.

The reason i got these big ones, is that they were the same price as ones 1/4 there size. I paid $15 Aust each/ $25 US, I think this is a good price.

Matt Au.

[ignesandros]

You might be able to use a thin carbide blade, constantly pouring water over the surface. I'd suggest a wet saw, but you'd be wasting too much of the magnet with any of the acceptable blades for one of them. If you move the magnet over the blade slowly and irrigate well, you shouldn't heat it beyond its critical temperature.

-Andrew

[scoraigwind]

"I have got hold of some very cheap 100mm/25mm/9mm Neo Magnets which i intend to cut into 3 pieces being 33mm long, and use these for my next alt.

Does any one know how to cut these magnets without getting them hot."

Neo magnets need to be coated to protect them from corrosion.  I do not recommend cutting them as this willk damage the coating.  Once it is damaged the atmospheric moisture gets in and destroys the magnet.

[solarphil]

I was very interested in the way you are using perm magnets for the field on that auto alternator.

I have recently found that auto alternators are only about 60% efficient. Using  permanemt mags for the field excitation, does the efficiency increase?

I'm using a 24v truck alternator for charging 24v batteries and would like to develop a system with the highest charging efficiency possible.  Any ideas

Phil Aus

[DanB]

The efficiency of an auto alternator really depends on how much power its producing.  When producing near their capacity I think they are a good bit better than 60%.

for charging batteries from an engine, I would leave it unmodified.  'Good' regulation gets tricky when we remove the wound field and put perm magnets in there.

[Matt Au]

Hi Phil,

I agree with Dan, in that if you are using a 24V truck to charge a 24V batt bank via a petrol/diesel motor then it would be best to leave the standard exciter coil rotor alone.

The reg changes the strength of the field coils via the brushes depending on how much load is being drawn and how flat the batteries are.

Permanent magnet setups are more for direct drive wind & hydro turbines which need every bit of efficiency they can get, and with an early cut in voltage, you could not use a PM 24 truck alt to charge a 24V batt bank as the cut in speed would be too high, but using a 12V bank the 24V alt reaches it`s cut in voltage earlier.

You also need a dump load to be activated when the batt is full, allowing the turbine to allways be loaded.

IMPORTANT: Using petrol/diesel engines with standard car/truck reg`s are made for charging small 50-80AH batteries,

and only put their full power out when there is a given load.

When the batteries get to about 13.5V with a 12v setup the 40Amp alt will only put in 2-5Amps as any more would damage the small car batterie but not a 500AH bank.

This is why I recommend disconnecting the two wires from the brushes to the reg and connecting them via a large variable resistor, then to the batt bank, which can be set at 70% max output, giving you 30Amps until the batteries reach say 14.4Volts.

This will cut down the run time of the engine and make good use of available horsepower.

When connecting a standard 40A bosch alt to a 3hp engine i got 25amps for one minute and dropped down to 3amps as the batteries reached 13.4V, batts were still

150 Ah down. When converting the brushes, and giving the field coil a continous 10volts, the amps will stay around 30Amps continous until i turn the engine off.

Matt Au.

[solarphil]

Thanks DanB and Matt for your comments

I have taken off the reg and are using a field rheostat for output current control (around 60 A) which allows me to fully charge (95%) the 600 Ahr battery system I have.  My solar system finishes off the rest.

Phil H