TROUBLESHOOTING
ADVANCED MICRO CONTROLS INC.
14
Motor Problems
As noted above, sometimes a problem that appears to be with the motor is actually a problem
with the indexer. The SD17040C has a Self-Test feature that allows you to verify motor opera-
tion without an indexer. With power applied to the driver, toggle the SB4-1 switch. The motor
will begin to rotate clockwise at 60 RPM. You must remove power to the driver to end the self
test.
Please remember to return SB4-1 to its original position before cycling power to the driver.
Symptom
Solution
The motor has no holding torque.
1) If the Step/Fault LED is red, then a problem exists with the driver or
motor. Refer to Power Connector and Indicator LED’s on page 10 for
information.
2) If the motor rotates when commanded but has no holding torque,
then your Idle Current Reduction switch is set to the To 0% setting.
This setting removes motor current when the driver is idle for more
than one second. Other idle current reduction settings are available.
See Switch Settings on page 6 for more information.
3) The SD17040C ships with the motor current set to its minimum value
of 1.0 amp. It’s possible that it was not set for your application. See
Switch Settings starting on page 6 for the proper switch settings.
The SD17040C blinks its
STEP/
FAULT
LED green when pulses are
applied to the driver, but the motor
only emits a high pitch noise. It
does not rotate.
1) The acceleration or starting speed values may have been set too
high when the indexer was programmed. The motor may start to
accelerate and stall as the acceleration increases.
2) The Step Resolution may be set to a values lower than you are
expecting. For example, if the Step Resolution is set to 200 instead
of 400, the acceleration value is effectively doubled.
The motor only runs in one direc-
tion.
This problem is usually caused by the directional pulse inputs. If your
indexer is sending pulses in the CW/CCW format and the driver is config-
ured for the Step & Direction format, the motor will rotate counter-clock-
wise when the driver receives CW pulses, and it will not rotate at all when
the driver receives CCW pulses. If the indexer is sending pulses in the
Step & Direction format and the driver is configured for the CW/CCW for-
mat, the motor will only rotate clockwise, even when the indexer is com-
manding a counter-clockwise move.
The motor runs backwards. (CW
instead of CCW and/or CCW
instead of CW)
1) One of the motor phases may be reversed. The “quick fix” is to
reverse the connections on the ±B windings.
2) There may be a problem with the directional inputs. Either they are
wired incorrectly or the format is wrong. Check wiring and see the
previous problem for more information on problems with format.
As its running speed increases, the
motor begins to run rough, and
eventually stops while pulses are
being applied.
1) If you are using single ended outputs for your pulse and direction sig-
nals, you may have a problem with the outputs not switching fast
enough. See the note on the R
LD
Resistor in the Connecting Your
Indexer section on page 7.
2) You may have a problem with resonance in the system. Run the sys-
tem with the Anti-Resonance feature enabled and disabled to see
which give you better performance. The Anti-Resonance feature is
set with SB1-5. See page 6 for more information.
The motor runs erratically.
1) The motor is not correctly coupled to the load.
2) The deceleration rate is set to high and the inertia of the load is carry-
ing the motor past the point where it is supposed to stop.
3) You are performing a slow move, (under 1 revolution/second) while
the Step Resolution is set to 200 or 400 steps/turn. To correct this
problem, try increasing the indexer’s starting speed parameter. Do
not increase the starting speed beyond your slowest running speed.
4) The motor current is set too low and the motor is unable to move the
load.
5) The motor is not correctly wired. Eight lead motors can be wired in
series or parallel. Series connection gives you more torque at lower
speeds and parallel connection gives you more torque at higher
speeds.
Summary of Contents for SD17040C
Page 15: ......
