Re: tachogenerator

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@...> wrote:

>
> 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
>

Yes Jon there are two sets of brushes parallel to each other,and
on the same commutator.The two brushes at 0 degrees are wired
together,and so are the other two 180 degrees apart.
I checked the ohm meter on it, @ the 200 scale it reads 0.02.
I checked a couple of treadmill motors I have here .002 and .003.
Quite a difference.
Thanks for the info guys.

Rick