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From: atec "atec77 on 9 Feb 2007 05:30 Andrew McKenna wrote: > jlittler(a)my-deja.com wrote: > <--- snipperage ---> >> >> And your statement is indeed correct - there's a difference between >> the mechanical input and the mechanical load. Pure semantics of >> course. mechanical load (as torque) plus electrical load(as torque) >> equals mechanical input required(as torque). The mechanical load is a >> constant (ceteris paribus), the electrical load changes with, well, >> the electrical load <grin> (1). To be more accurate the torque/turning >> force that you have to provide to generate a current equal to the >> current being drawn is increased as the current required increases(2) >> >> >> JL >> (1) there obviously being more than one meaning of the word load in >> this context - one being current drawn, the other being turning force >> required >> (2) still not sure I'm explaining that particularly well > > I wasn't going to shove my oar in again but that's such a good > translation I can't resist it. Of course you have to spin the > electricity generating thing faster if you want more electricity, > nobody's arguing that you don't. What I was saying was that the > increased electrical load does not cause engine RPM to drop, because it > can't. > > Simple test: drive a test vehicle (use Nev's) to a stadium with lights > and connect lights to a light circuit on the test vehicle (don't ask me > how, there seem to be a gadmillion electrical geniuses in here, you lot > figure it out). Step 2: turn on lights. If I'm wrong the test vehicle > will stall. If I'm right the lights won't come on but the test vehicle > will run normally. In fact if you take an ungoverned motor driving a genny it will in that circumstance slow in revs due to load increase which is why a governing unit is used to maintain speed , now do you agree ?
From: Knobdoodle on 9 Feb 2007 06:08 "Tim Moran" <tim-usenet(a)evilbastard.org> wrote in message news:MPG.203591da6461a6619896c3(a)freenews.iinet.com.au... > In article <1170907020.634294.244700(a)v45g2000cwv.googlegroups.com>, > jlittler(a)my-deja.com says... >> On Feb 7, 5:30 pm, Toosmoky <toosm...(a)hotmail.com> wrote: >> > Nev.. wrote: >> > > Toosmoky wrote: >> > There was a lot to take >> > in and I must admit I was somewhat amazed at the thinking that's gone >> > into them. A lot of current cars have such features. One that I forgot >> > about is an automatic fuel cutoff. >> >> Christ I had a 1979 Jaguar that had an auto fuel cutoff(1) > > I read that as Christ had a 1979 Jaguar > > I'm guessing crucifixion didn't seem so bad after that > One of the less talked-about "passions"........ -- Clem
From: Knobdoodle on 9 Feb 2007 06:15 "Theo Bekkers" <tbekkers(a)bekkers.com.au> wrote in message news:45cc05a9$1(a)news.bekkers.com.au... > Knobdoodle wrote: >> "Andrew McKenna" wrote: > >>> No, you need to push harder to get the result if you add electrical >>> load. It cannot possibly get harder to spin. > >> I bet if you said this 100 times it would still be just as hilariously >> stupid! >> >> What on earth are you actually trying to say? > > I think he's saying that if you turn an alternator with no load and with > full load, no extra power input is required. That must be why our back-up > gen-set gets louder when we put the air-con load on it. 3.9 litre John > Deere with a 3 phase 44kw alternator. > > Anybody want to tell me it doesn't use more fuel when we load it up to 40 > kw? > > Try holding one of these permanent magnet alternators in your hand and > spin the rotor with your other hand. Easy isn't it? Now twist the output > wires together and give it another spin. That would be max load. What do > you mean it stops dead? It surely doesn't require more turning force? > > Simple brakes for an induction motor is to short the terminals together. > This is wired into a lot of machinery. Stops very quickly. An induction > motor is the same design as your perm magnet alternator. > Now that you mention it; I think I read that the Qld electric and diesel-electric trains use this system for brakes. The added advantage is that without turning there's no back-EMF so they're essentially anti-lock. -- Clem
From: Knobdoodle on 9 Feb 2007 06:17 "MrMoped" <MrMoped49(a)hotmail.com> wrote in message news:TmVyh.5032$sd2.917(a)news-server.bigpond.net.au... > > "Knobdoodle" <knobdoodle(a)hotmail.com> wrote in message > news:NdFyh.4669$sd2.1501(a)news-server.bigpond.net.au... >> >> "MrMoped" <MrMoped49(a)hotmail.com> wrote: >>> Simple physics really! When switched on, the headlamp assembly pushes >>> the light beams forward (this is particularly noticable in the absence >>> of daylight), this is called an action. So using Newtons third law which >>> states that for every action there must be an equal and opposite >>> reaction, the same force applied by the headlamp to push the light beams >>> is then also applied to the vehicle, pushing it back! Extra petrol is >>> used to overcome the force applied by the headlamps. >>> >> [applause] >> But you've got red ones pushing you from behind and EVERYONE knows red >> ones are faster! >> -- >> Clem > True, as a general rule the red ones are faster and this has been a > concern to (most) motorcycle manufacturers worldwide. > > Having a fast red light at the rear of the motorcycle was a huge concern > in the early days of motorcycling as it was soon realised that having a > fast light (red) at the rear and a not-so-fast light at the front led to > the rear of the motorcycle trying to overtake the front at every > opportuity - this was deemed to be "not rider friendly". > > To counteract the power of the red light, a very mild or low wattage light > was fitted to the rear whilst a stronger/higher wattage light was fitted > to the front. This has worked very well. > > The ratio between front and rear light is very sensitive. A typical setup > of 60/55 watt high/low beam front light to 5 watt tail light works well in > most situations but the addition of a 20 watt brake light has added an > element of danger by making the motorcycle unstable. If you require proof > of tis, try the following: > > - ride along (at any speed) with the mind in neutral and then apply the > front brake as hard as you possibly can and do not ease off under any > circumstances. The rear of the motorcycle will rise and continue rising > until the red, rear light has overtaken the front. Some will try and > attribute this phenomenon to the action of the brakes but that is not 100% > correct. Squeezing the front brake as hard as you can imparts maximum > energy to the faster red light. A similar effect can be achieved by > applying maximum force to the rear brake. > > So yes the red lights are the fastest but they can be tamed with some > (un)sound engineering practices so as not to detract from the motorcycling > experience. My old mach111 certainly used to conform to this principle! -- Clem
From: Knobdoodle on 9 Feb 2007 06:27
"Hammo" <hbaj2006(a)aapt.net.au> wrote in message news:C1F1774F.1F39A%hbaj2006(a)aapt.net.au... > > > > On 9/2/07 12:34 AM, in article > YFFyh.4682$sd2.653(a)news-server.bigpond.net.au, "Knobdoodle" > <knobdoodle(a)hotmail.com> wrote: > >> >> "Nev.." <idiot(a)mindless.com> wrote: >>> I think you've been reading too many physics books and you've lost sight >>> of reality. Are you saying that if I measure something once per second >>> and then multiply that by 3600 my result is not an accurate measure of >>> an >>> hourly rate? Do you think the computer controlling the fuel rate just >>> guesses? >>> >> No; it actuates the injector the exact amount that it's been told to for >> the >> conditions it's measured. >> It then displays the exact mpg (L/Hr, Km per kilojoule or whatever) >> that's >> it's been told to display too. >> >> But it doesn't have any idea what a litre actually is and it certainly >> doean't have any ability to actually measure one! > > Eh? > > It's measured, but it can't measure? > Quantify "measured". -- Clem |