Doug
I also have tried to use a modern digital voltmeterIn the way you
describe. I don't believe that you are using the wrong approach it is
just that most digital voltmeters are not suitable.
I have tried using three different meters on three cars and they all
gave erroneous readings.
I believe the problem is that although there is generally thought to be
a steady charging voltage from the dynamo/generator, in reality it is
fluctuating at frequency created by the voltage regulator contacts
making and breaking in such a way that the field winding is controlled
to give the correct armature voltage.
Although the output of the dynamo is well damped these control
variations are still present at the output and are therefore not pure
Direct Current but a DC with an Alternating Current component
superimposed. Most digital voltmeter work by sampling the voltage for a
short period and then analyse this before giving you a reading. If the
sample voltage is taken at different points on the fluctuating DC then
the result will be as you describe.
I suggest that you use an older moving coil analogue meter before
looking for any other problems. It is quite likely that there is nothing
wrong with your dynamo and control box. A moving coil analogue meter has
sufficient inherent damping to give an average figure. This is how the
specification was written.
I would be interested to know how you get on.
All the best
>I just installed a new voltage regulator and had my generator rebuilt and I
>need to verify the output of the generator. Is there any reason I should be
>getting a reading that bounces around from 0 to 18 if my "new" digital
>voltmeter is working properly?
>
>
>
>I am checking the generator by touching the red lead to ground and the black
>lead to a jumper connecting both terminals on the generator.
>
>
>
>Thanks for your replys
>
--
John Harper
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