Re: [CAD_CAM_EDM_DRO] Re: tachogenerator

bondeoca wrote:

>
> Thanks Jon, I knew it wasn't a motor ,but a lot of sites say any
> dc motor can be run as a generator and visa versa. Do you know how
> the windings differ from a dc motor?
>

many turns of VERY fine wire, lots of armature slots and commutator slugs.
If your only purpose in life is to provide a smooth voltage to a 1000
Ohm load, the internal resistance of the armature is not a problem. If
you want to turn electricity into mechanical energy (instead of heat)
then resistance is the devil! Just measure the DC resistance between
the brushes.

You said earlier it had 4 brushes at 180 degrees. Does that mean two
sets of brushes parallel to each other? That might be a motor-generator
set. Electro-Craft patented that under the trade-name Moto-Matic. It
had a tach winding right in the same slots as the motor winding, and two
commutator sets, usually on the same end of the armature. But, the tach
winding had MUCH higher resistance than the motor winding.

If you really meant 4 brushes at 90 degrees, that is a typical 4-pole DC
motor, and you wire the opposite brushes together. So, going around the
motor, the brushes would be connected to + - + - .

Jon