Classic/Antique Car Repair: Ammeter readings, batt, cars

Question
Should the ammeter ALWAYS show a charge ? or does it only show charge according to draw ?

Answer
The ammeter should show a charge when it can overcome the draw and the engine is reving.  If you have no load on it, it will show a high charge rate, but as you load it up, the rate goes down and if you put too much of a load on it then it will show a discharge.
We run alternators on our cars and we don't have a problem with keeping the batt up.  There is no regulator on the old generator.  It puts out what it can, depending what you have it set for, and it will show a positive charge until the load exceeds the output.

jack