Epstein
Associates - K9APE®
K9APE® Machine Vision Inspection Systems
for
Commutators & Slip Rings
K9APE® Machine
Vision Inspection Systems are readily adapted for inspection of precision parts
with 360° convex surfaces - such as electric motor commutators
and slip rings mounted on armatures. Inspection can occur during or after the
manufacturing process.
The images shown below are from an armature
of a used fractional horsepower electric motor and highlight its commutator. When installed in a motor, the copper commutator interfaces with a pair of carbon brushes (not
shown) to carry current to windings (green wire) that magnetize the armature.
The commutator must have a smooth, defect-free
surface that is concentric with the armature's shaft to provide efficient,
reliable and quiet motor operation.
CLICK ON IMAGES BELOW FOR EXPANDED VIEWS
[Images May Take A Few Minutes To Download]
Used
Electric Motor Commutator Mounted On Armature
{Motor courtesy of Kelly's Appliance,
High-resolution 360° images of the surfaces
of commutators were captured with our K9APE®
Machine Vision Inspection System. A highly compressed image of a commutator of a typical part is shown below. Small defects
that could readily escape notice by human inspectors were readily detected on
uncompressed images.
360°
End View and Top View of Commutator
The previous image is a 360° combination End
View and Top View of the commutator.
The End View shows each of the copper commutator segments mounted on a plastic core. Note that
the center is lower than the ends. This is because the commutator
is not concentric with the rotational axis of the armature. Tiny eccentricities
and misalignments can be detected through automatic analysis of such images.
This view also shows that the all slots between commutator
segments have not been cut to the same depth.
The top view shows the surface condition of
each of the commutator segments. The track of the
carbon brushes is readily seen - as is the scratch on the sixth segment from
the left, which is also shown at the top of the commutator
in the color image above. The bright areas in the Top View image of the commutator occur because the commutator
surface is not concentric with the rotational axis of the armature. Because the
360° image shown here is highly compressed for INTERNET viewing, much of the
fine detail of the original image cannot be seen here.
In addition to the commutator
segments, the Top View also shows the solder tangs. Each of these can be
examined. Below the solder tangs are the windings and some of the armature core
sheet metal laminations. Note the waviness of laminations, which can be
measured for eccentricity by our inspection system.
The next image is a 360º view of a new commutator before assembly showing its solder tangs and
tang supports. Bent or damaged tangs or tang supports can be readily
identified.
360°
View of Commutator Tangs and Tang Supports
We have modified portions of this image with
enhancement algorithms and added three reference lines to demonstrate how tang
integrity can be confirmed.
360°
View of Commutator Tangs and Tang Supports
With Enhancement and Reference Lines
The image confirms that the phenolic base has been molded properly because the supports
for the tangs are all the same height. The tops of the tangs are all about the
same height. The curvature of the tangs can be measured by calculating angles
between side edges of the tangs and the three reference lines
The following image has been edited to show
only the top surface of each two commutators. The
purpose of this editing is to permit comparison between the two parts.
Each of the commutator
zones is the same height and each has been measured for area. This technique
provides a better measure of width should a zone not be a perfect rectangle. A dot
plot and a box plot were prepared from these data - as shown below.
These plots show that the zones of the top
part are more uniform in size than are the zones of the bottom part.
Statistical analyses of imaging data can be used to generate signals for
control of production machinery. The statistical plots shown above were made
using S-PLUS® 2000 Professional Statistical
Analysis Software.
CLICK ON IMAGES ABOVE FOR EXPANDED VIEWS
These images were captured with an EPIX®
PIXCI® Model D Imaging Board.
EPIX® XCAP™ Imaging Software was used for image formatting. The original files
have been JPEG-compressed for display here.
Manufacturing defects are readily detected
and measured by our K9APE® Machine Vision Inspection Systems. Images
better than JPEG-compressed quality can be obtained by our systems during
manufacture.
Epstein Associates - K9APE®
P.O.B. 400
+1
630 564 9292 - Voice & VM
Please
Use E-Mail - Facsimile
(-6 Hours GMT in Central Standard Time Zone)
(20 Miles North of
Sheldon
L. Epstein
Chief Engineer & Owner