When I did my time in the army as a sparky, they had an alternator test
stand that was an off the shelf design.

It had a vice type clamp to hold almost any model of alternator, generator
or starter motor I ever tried to mount on it.

Four big truck 6 volt batteries sat on the bottom shelf and the back panel
had voltage and current meters. It's drive motor was mains powered and had
variable position brushes that could be turned to either direction and would
cause the motor to develop more power the further you pushed them away from
neutral and in either direction of rotation. It gave out enough to drive the
big 100 amp 24 volt Landrover radio vehicle alternators to full load so it
had plenty of grunt.

Although I have never seen a similar unit in my travels, most alternator
repair places would have an idea about where these beasts might be supplied
from.

Hope this helps,
Peter

"Nathan Young" wrote in message
...
I want to build a teststand where I can test an alternator.

I plan on fabricating a test stand for the alternator.
I have a variable voltage source capable of driving enough current to
'drive' the field.
I have a dummy load to sink the output current.

What I need is a variable speed electric motor to drive the
alternator. But I am not sure how much horsepower is required to
drive a 60Amp alternator @ the equivalent of 2500 RPM at the prop.

Which brings up another question. What is the typical ratio of prop
RPM to alternator RPM? I am thinking it is 2:1.

Alternatively rather than wasting a bunch of my time - is this
something I could just buy from an alternator repair shop?

Thanks,
Nathan