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Ignoramus5857

On 2013-05-13, wrote:
On Sun, 12 May 2013 20:37:08 -0400, jeff wrote:

On Sun, 12 May 2013 08:22:58 -0500, Ignoramus5857
wrote:

On 2013-05-12, jeff wrote:
On Sat, 11 May 2013 22:01:48 -0400, jeff wrote:

On Sat, 11 May 2013 17:50:58 -0500, Ignoramus9202
wrote:

The Gorton 2-28 milling machine that I put in my shop recently, works
great, with one exception: its power feed for the X axis is not
working.

The way it is supposed to work is via a DC motor, controlled by a
simple DC drive. The DC motor has a field winding.

The problem is that the motor does not run.

The DC drive does supply voltage to both F1-F2 and A1-A2. I interpret
those as field and motor windings. F2 and A2 are connected together
and voltage between that point and F1 or A1 is 50 volts.

I opened the motor up. When opened, I tested voltage between brushes
and found out that there is 0 volts between brushes, or brushes and
armature.

How can I interpret this finding and what is the usual cause of such
behaviour.

The motor was really dirty inside, I washed it in a parts washer, but
have not yet reassembled, since I could not find the problem.

Thanks
F1and F2 Field A1 and A2 armature. Unhook all wires and check
continuity across f1 and f2 a1 and a2. Both should have very low
resistance. If your getting 50 volts in and out then sounds like
your missing the negative from the drive.
Is the motor fed voltage from the drive with two or four wires?

Three wires from the drive, connecting to four wires to the motor.

i
???? Guess I can't help you then. Most dc motors I work on require
either two or four power leads. Waiting to see what you find.
Common ground externally excited field shunt motor.. Speed changes
as the ballance between the feild and armature changes - the stronger
the field, the slower the engine.

To test the motor check continuity between f1 and f2, and between a1
and a2 with the motor assembled. If you have armature continuity and
not field continuity, you are likely to burn out the armature quite
quickly as the armature will be pretty close to a short. An open
field is pretty well indicative of a burned out field.

If the armature is open, turn the motor and see if it is intermittent.
If so, the armature is burned out. If not, there is a bad connection
from either A1 or A2 and the brush assigned to it.

Really a pretty simple thing to test - not necessarilly easy to fix..

If you have continuity on both, connect a1 to f1 and a2 to f2, and
connect jumper cables from 12 volt battery to the a1f1 and a2f2
connections and the motor should run.. Connect a1f2 and a2f1 and the
motor should reverse.

If that works, your "drive" or controller is damaged.

Yep. I will check all that tomorrow.