Re: dc spindle motor control.

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

> jeff35m_73068 wrote:
> ty jon. that helps alot. I new the shunt motor would make more

torque. I did connect it that way first; the motor did not seem to
like that connection, and there was a small amount of smoke coming
from the brush area of the motor. Do you think a reostat would fix
it? I will try to find the label that was in the wiring cabnet. There
were a couple other wires which i figured were temp sensors. I will
also take a pick which may help.

> >I am working on a fuji electric dc spindle motor. This is on a

large

> >Makino vertical mill, that had a 3000c control.
> >
> >I would like to increase the speed of this motor. Would simply
> >increasing the voltage do this? This spindle motor was connected

to a

> >fanuc 3000c controler(which is all missing). The motor itself has

5

> >wires coming from it. 3 from the armature area, and 2 from the
> >fields. The motor runs the best with the fields connected in

series

> >with the armature. Is anyone familure with this type of motor
> >control? What did this 3rd wire do? ty jeff
> >
> >
> I can't tell what the 3rd wire is for. It may be a safety ground

(is it

> green, or green/yellow?) Or, it may be a connection for

commutating poles.

> You say it runs best in series wound connection. If that is

compared with

> not connecting the field at all, that is no surprise. But, that

will

> give HORRIBLE
> speed regulation under load. Also, since this is most likely

designed for

> shunt field connection, it is not likely to perform well at all

under

> load in series field
> connection. You can tell by measuring the field resistance. It

will

> either be
> under one Ohm, if actually designed for series operation, or tens

of Ohms if

> designed for shunt. Does it have a specification plate?
>
> Generally, for shunt operation, you can run the field at a higher

current

> for low-speed, high-torque operation, and reduce field current for
> high-speed, low-torque. It acts just like a gear shift.
>
> Jon