Hi all
I have a DC motor from a old RC car and I want to make it into a AC
generator with an output of around 8V or greater. But when I run it from a
drill the output that I get at the terminals is 0.8V. If I were to rewind
the motor with a finer wire would that increase the output or just the
current produced? Also is you have any other suggestions on how to get a
greater voltage thats will be great.
Thanks in advance
It is unlikely your drill spins as fast as the motor did when running
as a motor, so your output voltage will be lower. More turns of finer
wire will raise the voltage (and lower the safe current).
You can't get AC from a DC motor because the motor has a commutator.
The commutator is a series of segments that essentially keep the
armature changing magnetic polarity (make it act as if it were driven
with AC) with respect to the field. Reverse the process, and DC comes
out.
Most small AC generators spin permanent magnet(s) in a stationary
field (easier to make and no brushes or slip rings to worry about).
If you want to tinker and have a source of parts, stepper motors make
ac when you spin them. They come in a wide range of voltages and
currents. They usually have a lot of poles so the output frequency
will be high.
Split phase capacitor motors (AC mains types) can be run as AC
generators with outputs similar to the mains and relatively high
currents.
Synchro Selsyns can be used to make AC. Armature and field have
windings and armature has slip rings. They are a sort of rotating
transformer. Feed DC to the armature/rotor (or field) and take AC
from the Field (or armature) while spinning the shaft. Synchro's are
dinosaurs that were used as computers and remote positioning
applications in WW2.
You don't say why you want AC, but if it is a frequency sensitive
application, frequency changes with speed and the number of poles, so
things like transformers or AC motors may not be happy with higher or
lower frequencies than they are designed for.