Alt or Battery died in a two mile drive!
#17
01-15-2006, 03:20 PM
Originally Posted by Thudpucker
mmmmm lets see here. An Auto is a big Series-Parallel circuit with two Power sources.
The Alt puts out a high amplitude AC signal. That has to be modulated by the Regulator which is usually in the Alt on most of the new auto's.
So...if we disconnect the Battery while the Engine is running. The Regulator sees the Battery's absense as a "LOW" signal and excites the Alt to full Charge.
The Alt goes to work, the signal goes high, but the Regulator wont let that High Amplitude signal go past the FIlter in the output section of the modulator.
(Right here I have a problem. Where does the small voltage Exciter source come from.
That's usually from the Battery. The Alt needs to make an electromagnet out of the armeture to produce the High amplitude signal?)[I]
So nothing should happen to any componants in the Charging system, or in the associated logic systems when you disconnect the Battery.
However IF you re-connect the battery something different happens. Then you might get a Surge from the Alt, depending on the Regulator circuit.
That could do some damage if the Circuits being discussed dont have some kind of an impedence filter on the incoming Voltage and Logic lines.
That's my understanding of the system.
The Alt puts out a high amplitude AC signal. That has to be modulated by the Regulator which is usually in the Alt on most of the new auto's.
So...if we disconnect the Battery while the Engine is running. The Regulator sees the Battery's absense as a "LOW" signal and excites the Alt to full Charge.
The Alt goes to work, the signal goes high, but the Regulator wont let that High Amplitude signal go past the FIlter in the output section of the modulator.
(Right here I have a problem. Where does the small voltage Exciter source come from.
That's usually from the Battery. The Alt needs to make an electromagnet out of the armeture to produce the High amplitude signal?)[I]
So nothing should happen to any componants in the Charging system, or in the associated logic systems when you disconnect the Battery.
However IF you re-connect the battery something different happens. Then you might get a Surge from the Alt, depending on the Regulator circuit.
That could do some damage if the Circuits being discussed dont have some kind of an impedence filter on the incoming Voltage and Logic lines.
That's my understanding of the system.
Here is the most basic description of the charging system on a vehicle I can find. Anybody without a BSEE, along with some people with a BSEE should be able to understand it. Note the WARNING in this description:
http://www.bcae1.com/charging.htm
#18
01-15-2006, 03:25 PM
Originally Posted by mat-helm
I'll be glad to respond to a resoned argument. Big fonts don't change facts. If you need me to, I'll be glad to explane what an isolated circuit is but it's been my exsperence that "ol wives tales" don't die in the face of facts.
#19
01-15-2006, 03:58 PM
I actually done 3 semester pretty close to you at State. But my degree was issued from USC. But what dose inductance have to do with what I said? I never said there weren't spikes in the system. What I said was that all the electronics in OBD2 cars were "isolated" from any spike the alt or battery are capable of producing. When I graduated in 88 that was the big push ( Harding IC chips). Back then if you weren't wearing a static strap you "would" screw up a chip. In 93 when I took a couple refresher Trig classes, this had pretty much been perfected and unless you were playing with some 555's the chance of screwing up a chip with static was almost nonexistent (even though I still have my static strap)..
Gotta stop here, missing the Panthers game here. Sorry bout the can of worms. Don't disconnect your battery if you don't want to, I mean hey, I still wear my static strap.
Gotta stop here, missing the Panthers game here. Sorry bout the can of worms. Don't disconnect your battery if you don't want to, I mean hey, I still wear my static strap.
#20
01-15-2006, 06:35 PM
