19
CANNON
®
CT-1000 Constant Temperature Bath
Revision 3.1a—February, 1998;
CANNON
®
Instrument Company
P.O . Box 16 • State College, PA • USA
B
APPENDIX B
—
CORRECTING
SHAFT & IMPELLER
MISALIGNMENT
Motor-stirrer units supplied by
CANNON
®
Instrument Company are
checked after assembly to ensure minimum run-out (deviation from
concentric rotation) at the impeller end of the shaft. The following
instructions are intended to assist those who may be experiencing exces-
sive vibration in the motor-stirrer because of shaft run-out or misalign-
ment of the impeller blades.
NOTE
See the instructional video on the CT-1000 for a detailed description of the
procedure described below.
Set Screw Alignment
The motor shaft contains a flat area. The coupling should be oriented in
such a way that the set screw is aligned with the flat. The stirrer shaft
and motor shaft should be inserted to approximately the same length in
the coupling.
You can test for shaft run-out and impeller blade alignment by placing the
motor on a soft surface with impeller facing up. Connect the motor to the
appropriate
AC
power source and observe the impeller and shaft. If run-
out is severe, the motor will vibrate and the shaft will flutter noticeably.
The impeller will appear blurred if the impeller blades are not in the same
plane.
If necessary you can adjust the impeller blades by bending the large
horizontal sections of each of the four segments so that they lie in the
same plane. Since these segments are easily bent, check alignment
whenever the impeller is bumped, or if there is any suspicion that the
blade segments may have become misaligned.
Shaft run-out correction
The following procedure is suggested to correct shaft run-out:
Grasp the motor firmly with the left hand and touch the tip of a soft
crayon (a glass marking pencil, for example) momentarily to the side of
the shaft near the impeller end while the motor is running. It is advisable
to remove the impeller while carrying out this procedure. The mark
produced by the crayon will be evident as a line part way around the
shaft.