Ameter ?s

[matthon]

OK, I searched and found some info on an ameter, but I am still confused.
I have a vintage SW ameter, 2 black wires on the back.
It might just be that I do not know the terminology that is causing the confusion; so how do you connect an ameter?
Are there additional parts needed?

 

[RedFish]

Amp meter will have 2 wires , one on eash post. Very early might have both black rather than a red and a black. Either way one is hot from the fusable link and the current goes across the gauge to the other wire.
Does this answer your question ?

 

[goldduster318]

The main charging Circuit current has to fully flow through the Ammeter. I personally would suggest against using one at all and using a voltmeter instead to monitor your charging system.

 

[matthon]

So an ameter measures current, specifically the current passing through the ameter, and a volt meter measures the difference between two points?

3 questions:
What is the wire that the ameter is spliced into?
What 2 wires is a volt meter hooked into? (its 2 right, or 3?)
Is the downside to the ameter that you actually have current running through the interior of the car?

I have 3 SW gauges, all match, all old, and I would like to make the ameter work as long as it is safe.

 

[goldduster318]

So an ameter measures current, specifically the current passing through the ameter, and a volt meter measures the difference between two points?

3 questions:
What is the wire that the ameter is spliced into?
What 2 wires is a volt meter hooked into? (its 2 right, or 3?)
Is the downside to the ameter that you actually have current running through the interior of the car?

I have 3 SW gauges, all match, all old, and I would like to make the ameter work as long as it is safe.

1: The charging wire from the stud on the back of the alternator on its path to the battery
2: The volt meter needs a keyed power source (can be from anywhere) and a ground for it to work. Then there is usually one more wire for lights
3: Yes, that and it makes the charging path longer and less effective at charging the battery. The stock setup is like this as well. Mine is modified as shown at http://www.madelectrical.com/electricaltech/amp-gauges.shtml

You might want to take a look at summit. Stewart Warner started making a lot of the old type gauges again.

The volt gauge will require almost no current and is a safe design and you won't melt it if you upgrade the alternator at a later date. It just measures the potential difference between your keyed power source and the ground. The amp gauge measures the full flow of current through whatever its connected to. If its not the main charging wire, it won't tell you anything.

 

[blue missile]

Does anybody know of someone who makes a CT type ameter for a car?
They work like the CT type of electric meters where the main hot (or one of them in the case of 2 and 3 phase power) lead is passed through a coil type of sensor which picks up the ammount of current flowing through the main transfer wire. This would not put it in the charging path.
One of the main advantages of an ameter is if you have alot of draw, you can monitor weather or not there is a surplus going to the battery.
However with a volt meter there is no way to tell if you are over drawing the system.
Andrew

 

[goldduster318]

One of the main advantages of an ameter is if you have alot of draw, you can monitor weather or not there is a surplus going to the battery.
However with a volt meter there is no way to tell if you are over drawing the system.
Andrew

If you're drawing the battery down, you'll get a voltage drop, if the battery is charging fully, you'll find your voltmeter reading between 14.2 and 14.6v

This is as a result of Ohm's Law. Voltage=Current X Resistance or alternatively Power (watts)=Current X Voltage.

Amp meters were gone on all cars starting in 1990 and on almost every non mopar vehicle by the mid 70's. If it was better they would not have dropped it.

 

[blue missile]

Well said physics trumps lack of recall or knowledge any day:idea1:
Andrew

 

[cudaman51]

for dc it would be a very low value resistor. I think its called a shunt.It would not be a current transformer because dc does not pass through a transformer.It,s just a milivolt meter across a resistor in series with the current that you want to measure.If you found one you wouldn,t want to pay the price.