OK, first off that lumens amount listed is WAY OFF. I mean WAY THE EFF OFF! It calculates out to 14600 lumens per watt. The theoretical maximum efficiency lighting is 683 lumens per watt at 555nm, but for white light the maximum efficiency is even lower at 240 lumens per watt. A high temp halogen bulb usually achieves around 35 lumens per watt. This works out to 250W bulb putting out around 8750 lumens. This is achievable with a 75W HID ballast and bulb. A 75W HID system assuming 80% efficiency works out to 7.82A@13V per light, instead of 19.2A@13V. This takes your calculation down to 62.56A or ~800W. Still nothing to sneeze at but definitely doable.
As for the 70W ballast, they are available for aircraft usage.
As for the 70W ballast, they are available for aircraft usage.
hiya 1more...
Thanks for that. I'm not sooooo old that I exist in the days of mechanical regulators (although I was trained on them...)! And for my various sins I actually taught this stuff for a few years - training profesional auto engineers in electronics and electrical systems.
By IRA I assume you mean Internally Regulated Alternator. I'm not aware of any that have the capability to measure rotational speed but I'd love to see a reference to them if you have it!
Agree with you about the use of a stand-alone generator - in the situation our OP has its the only really practical solution I can think of. I'd split the load so that lighting and other vehicle functions came from the engine alternator and any ancilliary stuff was supplied by a separate genset.
Thanks for that. I'm not sooooo old that I exist in the days of mechanical regulators (although I was trained on them...)! And for my various sins I actually taught this stuff for a few years - training profesional auto engineers in electronics and electrical systems.
By IRA I assume you mean Internally Regulated Alternator. I'm not aware of any that have the capability to measure rotational speed but I'd love to see a reference to them if you have it!
Agree with you about the use of a stand-alone generator - in the situation our OP has its the only really practical solution I can think of. I'd split the load so that lighting and other vehicle functions came from the engine alternator and any ancilliary stuff was supplied by a separate genset.
I think Pedro's suggestion to use HID lights instead makes a lot of sense from both service life and energy usage standpoints. One big alternator would probably run them all...
there is a big debate here for these HID lamps some guys swear by them and think they are great. however i have seen them last 24-48 hours pretty consitantly in off road aplications they dont seem to like the cold and the box (i think its the transformer) doesnt like vibration. but the 2 things that seems to kill these systems dead is turning them on and off for passing traffic and rougue flying rocks smashing them out. i realize there isnt much anyone can do about the rocks but its a lot easier pill to swallow changing out a 20$ bulb vs a HID
i figured the lumen thing was off but for the price of the bulbs they are brighter then most of the daylighters and other purpose built lights and dirt cheap.
you guys will like this one.....there is a guy here running 2x 1000w metal halide bulbs on his roof and he built a shutter system like a light house that closes for on coming traffic while the bulb stays on. again tho not so good for vibration and more of a headache then i think its worth.
i still would like to know if it is possible to find a ratio from rotor to field windings or figure out how i can feed larger current in to get larger current out, and try to start figuring out how to build my own alternator or modifying an alternator. what is the difference between a 100amp alternator and a 150amp alternator? i think when i figure this question out i can apply what is different, into turning a 150a into a 200a. no?
i figured the lumen thing was off but for the price of the bulbs they are brighter then most of the daylighters and other purpose built lights and dirt cheap.
you guys will like this one.....there is a guy here running 2x 1000w metal halide bulbs on his roof and he built a shutter system like a light house that closes for on coming traffic while the bulb stays on. again tho not so good for vibration and more of a headache then i think its worth.
i still would like to know if it is possible to find a ratio from rotor to field windings or figure out how i can feed larger current in to get larger current out, and try to start figuring out how to build my own alternator or modifying an alternator. what is the difference between a 100amp alternator and a 150amp alternator? i think when i figure this question out i can apply what is different, into turning a 150a into a 200a. no?
in essence you cant feed a larger current to the rotor - its limited by the ability of the brushes and slip rings to handle the current without arcing and burning, and the ability of the regulator to control the current without exceeding the pass device's limits. In most practical applications, this limit is around 2 amps @ 12 volts.
Reality is that it wouldn't matter - the current-limiting inductance of the stator windings will kick in at around the same point regardless of the field strength of the rotor.
As I've already said, the difference is NOT the rotor, its the winding of the stator.
You could try rewinding a stator with a heavier gauge wire and fewer turns. You could also try a delta rather than star winding pattern. Either of these will reduce the inductive effect in the windings and increase current output capability. However, it will also impact the output voltage by lowering it...
For all the shagging around, an off-the-shelf product is more likely (by orders of maginitude) to provide a workable solution.
Reality is that it wouldn't matter - the current-limiting inductance of the stator windings will kick in at around the same point regardless of the field strength of the rotor.
As I've already said, the difference is NOT the rotor, its the winding of the stator.
You could try rewinding a stator with a heavier gauge wire and fewer turns. You could also try a delta rather than star winding pattern. Either of these will reduce the inductive effect in the windings and increase current output capability. However, it will also impact the output voltage by lowering it...
For all the shagging around, an off-the-shelf product is more likely (by orders of maginitude) to provide a workable solution.
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Have you looked at the 55 or 62 series alternators from the following company?
Custom 12 and 24 volt Motor Coach and Truck High Output Alternator
Custom 12 and 24 volt Motor Coach and Truck High Output Alternator
Typically tractor (truck) alternators are brushless type. Automotive alternators (light trucks and smaller) use brushes. A brushless alternator is constructed as two alternators on the same shaft (one power generating alternator and one exciter); they are always physically larger than automotive types.
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