Antonio I0JX wrote:
I am not familiar with that particular dynamotor, so I am unable to tell you
which lead is positive and which negative (although it should not be too
difficult to determine it).

Some of them will run properly in reverse, and of course you get reverse
voltage on the output.

In all cases, please be informed that dynamotors typically have a very high
inrush current. If you use a modern stabilized power supply, the overcurrent
protection will surely trip.

Figure if you have a 25A running current that your starting current is
50-75 amps. Not for very long, only for a very short time. Adding a big
capacitance can help if you're stuck using a current-limited supply.

HOWEVER, if you see anything higher than 25A running current under load and
it's rated for that, something is wrong. Before I would fire up an old
dynamotor, I would pull the thing apart, remove all old grease on bearings,
and relube everything with modern lubricants, and I would check the brushes
at the same time.

Old and crusty lube will increase your starting and running current and
eventually damage the bearings and overheat the motor windings.

After problem will be solved, I fear you will anyway want to build an
ad-hoc P.S. replacing the dynamotor. Most often dynamotors are so noisy one
can't stand them!

That's why you put it in the trunk of the car where it belongs.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."