Re: A little experiment on demagnetization

Ray,

Of course I did; once I set up the dyno it's way to cool not to.

It is of my design and uses a low inertia DC servomotor as the load
driven by a modified G320 drive. I have it driven by a G2002 6-axis
motion controller commanded by a PC over a USB interface.

The servomotor is 500W, has a Kt of 49.8 in-oz and is equipped with a
2,000 line encoder.

The test step motor is coupled to the servomotor via a helical
flexible coupling. A G201 drives the test motor. One axis of the
G2002 drives the G320 with a step frequency 4 times higher than the
axis driving the G201. This causes both to turn at exactly the same
speed.

I introduce a phase lag angle on the servo in 0.045 degrees "slip"
increments until the stepper is just about ready to stall; about 3.2
to 3.3 degrees total lag. The servomotor current reflects the torque
load applied to the stepper.

These 2 frequencies are then swept from 0 to 100kHz for the G201 and
0 to 400kHz for the G320 over a 30 second span of time. The whole
time the stepper is just a hair's breadth short of stalling.

Torque data is logged during this 30 second sweep period at 100 step
per second intervals (0.3 seconds) for 100 torque vs. speed points.

I presently output the analog torque data (along with freq "ticks")
to my digital storage scope to get graphical speed-torque
presentation. Good enough for what I need and I don't have the time
to polish it any further.

Mariss





The G2002 motion controller
--- In CAD_CAM_EDM_DRO@yahoogroups.com, Raymond Heckert <jnr@a...>
wrote:

> Quick question, "Did you dyno both motors before the experiment, to

make

> sure they had identical properties"?
>
> RayHex
>