Dynamo (Generator) Conversion - Series III

[ALC 68A]

My SIII is being professionally restored, with some upgrades to the electrics including conversion to an alternator, using one of those alternators inside a replica of the old dynamo (generator) casing. That keeps the engine bay looking original and also means the old brackets can be reused.

However, can I still use my original 30-0-30 ammeter, or will the higher output of the new alternator burn it out? Do I need to find a SV 50-0-50 ammeter? Also, can I reuse the original dynamo/generator pulley and fan belt? I have an idea that alternators generally have smaller pulleys, so will using the original generator pulley cause the alternator to overspeed? If so, how would I work out what size pulley and fan belt to use? Unfortunately, my restorer has no experience of using one of these alternators.

Or am I worrying unnecessarily!?

Regards

Steve G

 

[mikephillips]

I suspect it'll depend on the output of the alternator you get. A stock more or less output shouldn't make it an issue, but if you want more, then you probably want to get a higher amp gauge or bypass it.

 

[BobTR]

You might be able to put a shunt (a short piece of 16 gauge wire) across the terminals of the ammeter that would allow the ammeter to still be used. Google has some information on an electrical shunt.
Bob

 

[Tom H]

I have used my original ammeter even with a 50 amp alt. Correctly wired the ammeter shows how much current is going into or out of the battery. About the only time your ammeter will show a lot of current is just after starting, when the battery is a good bit drained. The alt will probably peg the ammeter, as it does on mine for a minute or two. Often it sticks at that pegged point, but a tap on the dial and it drops to correct reading. The problem with swapping to a higher amp meter is that you lose resolution and the ammeter is then less useful for measuring and understanding your electrical system. I’d suggest keeping your stock ammeter or changing to a voltmeter like many others have done.

Tom

 

[ALC 68A]

Thanks for the advice. The Dynalite alternator has an output of 45A. Regards.

Steve G

 

[Tom H]

Just keep in mind, the maximum current your Alt can push thru the ammeter into the battery (like 45A or 50 A), is nowhere near the max current your battery can push thru the ammeter into your electrical system, (like a coupe hundred A), so why worry about it.