Electrical Lesson Again Needed

[TR3driver]

Can an original ammeter be modified to include a shunt?

Not in the sense you are talking about, at least not a TR ammeter.

However, it is a good idea, IMO, to add a fusible link at the starter solenoid, which can help protect all of the heavy gauge portions of the wiring harness (not just the run to/from the ammeter). Then if there is a major short, the fusible link will blow hopefully before the harness melts.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]To give an example of how brief some manuals can be, [/QUOTE]
Or the TR3 owner's manual: "Ammeter. Indicates the flow of current into or out of the battery."

Still, an owner's manual isn't exactly the place to explain what "current" is, or what a "battery" is. They generally don't even tackle more important topics like stopping distance or cornering ability. The reader/driver is expected to have a certain amount of knowledge to begin with.

 

[Member 10617]

Randall,

You are right, but what I had in mind is some statement in the manual that would tell you how to interpret the ammeter, read the ammeter, understand the ammeter, or whatever. Otherwise, it's just a pretty glass bubble with a needle and numbers. Ironically, some of the manuals do explain what "current" is and what a "ammeter" is -- and all the ins and outs of a voltage regulator, etc., etc., -- but are mute on what the ammeter indicates to the driver.


Wouldn't it have been helpful if the TR3 manual had included the following (at the very least): "If the generator is pushing current into the battery (charging the battery) the gauge reads positive. If current is flowing out of the battery, it should read negative, and usually means that your charging system is not keeping up with the electrical demands....." and here is what to do about it....

And here is something from Charles Ofria, "A Short Course on Charging Systems" (at Familycar.com): "An ammeter will read from a negative amperage when the battery is providing most of the current thereby depleting itself, to a positive amperage if most of the current is coming from the charging system. If the battery is fully charged and there is minimal electrical demand, then the ammeter should read close to zero, but should always be on the positive side of zero. It is normal for the ammeter to read a high positive amperage in order to recharge the battery after starting, but it should taper off in a few minutes." Very helpful to the new owner.

 

[joejoecat]

Check out the Electrical Tech Section at www.madelectrical.com/electrical-tech.shtml .They do a nice job of explaining things and they have a great little Tech Book made simple.

 

[Member 10617]

Joe,

Thanks for the great link. There are a number of really useful links on the Internet. I don't want to become an expert on car "electrics" (as opposed to "electronics") -- nor do I have the capacity to become an "expert" -- but I do want to understand what I'm looking at when I glance at those gauges, both out of curiosity and a desire to make sure things are working as they should.

I'll look into the Tech Book...

 

[HerronScott]

Do modern cars really just have idiot lights ?

Sometimes they are disguised ... my buddy's Miata had an oil pressure "gauge" that ran from a switch :laugh:

That would be the 1995-1997 Miata (Bought a 1997 earlier this summer). Guess they felt the real thing confused too many people. :wink:

A real common upgrade is to install the 1990-1994 gauge and sending unit.....

Scott

 

[Member 10617]

Joe's link to MAD Electrical is a good one. Mark Hamilton's piece on "Voltage Regulator, Alternator, and Battery Operation" is a great example of what I have been talking about. He starts by writing: "The simple explanation is provided first, as not to leave out readers who only want a sort of overall view of how a system works, without getting too technical." For those who need more detail, he follows his "simple explanation" with much detail.

I think there was an "Operator's Manual" available (not the "Instruction Book, Triumph Sports Car TR3," issued by Standard-Triumph Sales Limited) for the TR3 back in the early days, but this book is rare and very hard to fine nowadays. I don't know if it explained the gauges as I have been suggesting, but I doubt it. Having such a manual, and not having to piece one together from a wide variety of sources, would make life with the TR3 a lot easier. But, on the plus side, cobbling together such a manual is an education, and an interesting one indeed.