Troubleshooting and fault elimination
Error elimination
Maloperation of the drive
9
9.4
9.4.1
9.4-1
EDSVF9333V EN 3.0-06/2005
9.4 Error elimination
9.4.1 Maloperation of the drive
Faulty behaviour Cause Remedy
An asynchronous motor
with feedback rotates in an
uncontrolled manner and
with low speed
The motor phases are reversed so that the rotating field
of the motor is not i dentical anymore with the rotating
field of the feedback system. The drive shows the
following behaviour:
z V/f characteristic control (C0006 = 5)
– The motor rotates faster than the speed setpoint by
the value set in C0074 (influence of the speed
controller, Lenze setting 10 % of n
max
). After the
controller is enabled it does not stop at zero speed
setpoint or quick stop (QSP).
– The setting motor current depends, among other
things, on the set value of the U
min
boost (C0016)
and can rise to I
max
(C0022). This may activate the
fault message OC5.
z Vector control (C0006 = 1)
– The motor rotates slowly with maximum slip speed
(depending on motor data and maximum current)
and does not react to a speed setpoint. The
direction of rotation is determined by the sign of
the speed setpoint.
– The motor current rises up to I
max
(C0022). This
may activate the fault message OC5 with a time
delay.
z Check motor cable for correct phase
position.
z If possible, operate the motor with
deactivated feedback (C0025 = 1) and
check the direction of rotation of t he
motor.
Motor does not rotate
although the controller is
enabled (
is off) and a
speed setpoint has been
specified.
Both terminal strips X5 are reversed. Since X5/A1 and
X5/28 face each other, the controller can be enabled if
the control terminals are internally supplied. All other
connections, however, are assigned incorrectly so that
the motor cannot start.
Check the position of the terminal strips:
z If you look at the connection terminal
in reading direction, the left terminal
strip X5 must be connected with the
input signals and the right terminal
strip X5 must be connected with the
output signals.
The monitoring of the
motor phases (LP1) does
not respond if a motor
phase is interrupted,
althoughC0597=0or2
The function block MLP1 is not entered into the
processing table.
Enter the function block MLP1 into the
processing table. The function block MLP1
requires 30 μs of calculating time.
If during high speeds
DC-injection braking (GSB)
is activated, the fault OC1
(TRIP) or OU (TRIP) occurs
During DC-injection braking the controller sets pulse
inhibit for a short time (DCTRL-IMP) to reduce the
magnetisation in the motor before a DC voltage is
injected into the motor. At high speeds (e. g. in case of
mid-frequency motors) the residual voltage which
develops from the residual magnetism and high speed
can generate such a high motor current that OC1 or OU
is activated.
Prolonging the duration of the pulse
inhibit:
z Apply the output signal DCTRL-IMP to
the function block TRANSx and adjust
the desired switch-off time there
(usually 500 ms). If DCTRL-CINH1 is set
to HIGH, the duration of the pulse
inhibit is prolonged by the time
adjusted.
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