Ammeter removal
Race Director
Joined: Apr 2007
Posts: 11,152
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From: South Western Ontario
Maybe you can't measure the voltage drop on the 2' piece of 10 gauge wire used as a shunt when < 60A flows, but the ammeter in a C3 has no problem doing it.
Last edited by lionelhutz; Jul 31, 2014 at 02:50 PM.
Le Mans Master
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From: Fernandina Beach FL
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Irony- a literary technique, originally used in Greek tragedy, by which the full significance of a character's words or actions are clear to the audience or reader although unknown to the character.
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
Now you're describing your completely off topic posts? Your "feigned ignorance" about what you are doing? Because off topic crap like this is very ignorant.
Last edited by lionelhutz; Jul 31, 2014 at 08:29 PM.
Le Mans Master
Joined: May 2003
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From: Fernandina Beach FL
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Really?
Feign ignorance-
Description
If the other person wants to talk about something and you do not, then you can sometimes shorten the conversation (or even kill it stone dead) by pretending that you know little or nothing about the subject.
This is particularly useful when they are seeking information from you. It is not useful when they feel knowledgeable and want somebody else to listen.
Apologize and say that you know nothing. If they persist and start talking about the subject anyway, you can continue to profess ignorance or use another method.
Example-
Sorry, but I know nothing about that.
I'd love to help, but that's not my area of expertize.
Sorry, but I don't understand what you are talking about.
Mmm. You're the expert here -- I can't add anything to what you already know.
Discussion
When you have nothing to say about a subject, then by definition, the conversation gets shorter -- unless the other person decides to tell you all about it.
Sometimes people will ask you about something where they know the answer and more -- they just want to start a conversation in which they can expound at length and 'be the expert'. In such cases, other methods of closing the conversation may be more appropriate.
Feign ignorance-
Description
If the other person wants to talk about something and you do not, then you can sometimes shorten the conversation (or even kill it stone dead) by pretending that you know little or nothing about the subject.
This is particularly useful when they are seeking information from you. It is not useful when they feel knowledgeable and want somebody else to listen.
Apologize and say that you know nothing. If they persist and start talking about the subject anyway, you can continue to profess ignorance or use another method.
Example-
Sorry, but I know nothing about that.
I'd love to help, but that's not my area of expertize.
Sorry, but I don't understand what you are talking about.
Mmm. You're the expert here -- I can't add anything to what you already know.
Discussion
When you have nothing to say about a subject, then by definition, the conversation gets shorter -- unless the other person decides to tell you all about it.
Sometimes people will ask you about something where they know the answer and more -- they just want to start a conversation in which they can expound at length and 'be the expert'. In such cases, other methods of closing the conversation may be more appropriate.
Le Mans Master
Joined: Jul 2006
Posts: 8,117
Likes: 104
From: charlotte north carolina
OK, back to the topic.
After taking measurements, I can report this- the ammeter requires 2.2 amps to show a 40 amp deflection, and has a 0.1 voltage drop across the terminals at that level. This indicates a coil resistance of 0.05 ohms. This is within previous estimates. Given that #10 copper wire has 0.001 ohms per foot (google that), a 40 amp draw thru three feet of that wire would cause a voltage drop of 0.12 volts. So, Ohms Law seems to work here(given the inaccuracies of my measurements). There are no voltage divider resistors in this circuit as would be found in a "volt meter" circuit. This meter was designed to be a true ammeter that indicates current flow thru the power lead, not it's voltage. The fact that a voltage drop occurs is immaterial. Current doesn't flow unless there is a voltage potential difference. If GM wanted this meter to reflect voltage instead of amperage, the meter would have been designed and installed as in later year cars.
After taking measurements, I can report this- the ammeter requires 2.2 amps to show a 40 amp deflection, and has a 0.1 voltage drop across the terminals at that level. This indicates a coil resistance of 0.05 ohms. This is within previous estimates. Given that #10 copper wire has 0.001 ohms per foot (google that), a 40 amp draw thru three feet of that wire would cause a voltage drop of 0.12 volts. So, Ohms Law seems to work here(given the inaccuracies of my measurements). There are no voltage divider resistors in this circuit as would be found in a "volt meter" circuit. This meter was designed to be a true ammeter that indicates current flow thru the power lead, not it's voltage. The fact that a voltage drop occurs is immaterial. Current doesn't flow unless there is a voltage potential difference. If GM wanted this meter to reflect voltage instead of amperage, the meter would have been designed and installed as in later year cars.
Le Mans Master
Joined: Aug 2006
Posts: 7,431
Likes: 1,561
From: mount holly NC
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Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
OK, back to the topic.
After taking measurements, I can report this- the ammeter requires 2.2 amps to show a 40 amp deflection, and has a 0.1 voltage drop across the terminals at that level. This indicates a coil resistance of 0.05 ohms. This is within previous estimates. Given that #10 copper wire has 0.001 ohms per foot (google that), a 40 amp draw thru three feet of that wire would cause a voltage drop of 0.12 volts. So, Ohms Law seems to work here(given the inaccuracies of my measurements). There are no voltage divider resistors in this circuit as would be found in a "volt meter" circuit. This meter was designed to be a true ammeter that indicates current flow thru the power lead, not it's voltage. The fact that a voltage drop occurs is immaterial. Current doesn't flow unless there is a voltage potential difference. If GM wanted this meter to reflect voltage instead of amperage, the meter would have been designed and installed as in later year cars.
After taking measurements, I can report this- the ammeter requires 2.2 amps to show a 40 amp deflection, and has a 0.1 voltage drop across the terminals at that level. This indicates a coil resistance of 0.05 ohms. This is within previous estimates. Given that #10 copper wire has 0.001 ohms per foot (google that), a 40 amp draw thru three feet of that wire would cause a voltage drop of 0.12 volts. So, Ohms Law seems to work here(given the inaccuracies of my measurements). There are no voltage divider resistors in this circuit as would be found in a "volt meter" circuit. This meter was designed to be a true ammeter that indicates current flow thru the power lead, not it's voltage. The fact that a voltage drop occurs is immaterial. Current doesn't flow unless there is a voltage potential difference. If GM wanted this meter to reflect voltage instead of amperage, the meter would have been designed and installed as in later year cars.
So this is what everyone else has been saying all along. By your numbers, 40 amps in the 10 gauge wire causes a 0.1V drop between the ammeter connections. The meter "measures" the 0.1V and deflects to 40A on the scale. The current that flows through the meter itself is immaterial to its operation.
And none of this changes the fact that the only correct answer to the question is that the wires should be disconnected when the meter is removed.
Last edited by lionelhutz; Aug 4, 2014 at 10:03 AM.
Le Mans Master
Joined: Jul 2006
Posts: 8,117
Likes: 104
From: charlotte north carolina
You're correct, I surrender, I give up, I relinquish all claims, I admit that I'm a worthless individual, I bow to your superior intellect. I also now realize why I didn't choose teaching as a profession.
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