How to Produce DC Electricity

[MikeM3]

Hi, to you all, I have a question that is puzzling me and has been
for some time.

Years ago if you wanted a wind generator, to supply 12v, you got
a dynamo and a fan, unfortunately it is not so simple today, this is
progress!

We do know that wind turbines, are DC Dynamos, because they can
generate, usable electricity at slower speeds.

We also know that modern cars, use AC alternators, whose output
is rectified and reduced to 12v DC.

We also know that some DC motors are brushless and not all can be
used as Dynamos, why, I don't know.

Can anybody suggest, honestly, which can be best used to supplement
a solar system, to keep the batteries as fully charged as possible.

I have read that not all brushless motors will act as generators, but in my
day, I am 83 years old and probably a dinosaur to most of you, we knew,
that if we supplied power to the DC unit, that it would run, we also knew,
that if we mechanically rotated it at any speed, it would produce electricity,
to my way of thinking, although we have progressed technically, in leaps
and bounds, in some ways we have gone backwards!

So, my question is what is the best machine for my project

Thank you for taking time to read this and hopefully answer, knowledgeably.

Mike.

 

[Simon47]

Are you familiar with a stepper motor ? If so, then a brushless DC motor is a bit similar in that electronics switch power to different windings in sequence to make it move.
That's why you can't use one as a generator.

You are also wrong by assuming wind turbines use DC generators. Some smaller ones might, but on a commercial scale they really don't want the commutator & brush gear (carbon dust & maintenance). There isn't really much difference between a dynamo and alternator for low speed operation - both scale output (IIRC) proportional to speed (for a constant rotor field current).

For a small unit, what is "best" will depend a lot on what you have to hand. Then it's a case of matching the turbine design so it's torque/speed characteristics match the generator torque/speed/output characteristics.