Operating Instructions

Faults and Alarms
List of Faults and Alarms
3-682
© Siemens AG 2011 All Rights Reserved
SINAMICS G120 Control Units CU230P-2 Parameter Manual (LH9), 06/2011
A07401 (N) Drive: DC link voltage maximum controller de-activated
Reaction: NONE
Acknowledge: NONE
Cause: The Vdc_max controller can no longer maintain the DC link voltage (r0070) below the limit value (r1242, r1282) and
was therefore switched out (disabled).
- the line supply voltage is permanently higher than specified for the power unit.
- the motor is permanently in the regenerative mode as a result of a load that is driving the motor.
Remedy: - check whether the input voltage is within the permissible range.
- check whether the load duty cycle and load limits are within the permissible limits.
A07402 (N) Drive: DC link voltage minimum controller active
Reaction: NONE
Acknowledge: NONE
Cause: The DC link voltage controller has been activated as the lower switch-in threshold has been undershot (r1246,
r1286).
The kinetic energy of the motor is used to buffer the DC link. The drive is therefore braked.
See also: r0056 (Status word, closed-loop control), p1240 (Vdc controller or Vdc monitoring configuration (vector
control)), p1280 (Vdc controller or Vdc monitoring configuration (U/f))
Remedy: The alarm disappears when power supply returns.
F07405 (N, A) Drive: Kinetic buffering minimum speed not reached
Reaction: OFF2 (IASC/DCBRAKE, NONE, OFF1, OFF3, STOP2)
Acknowledge: IMMEDIATELY
Cause: During kinetic buffering the speed fell below minimum speed (p1257 or p1297 for vector drives with U/f control) and
the line supply did not return.
Remedy: Check the speed threshold for the Vdc_min controller (kinetic buffering) (p1257, p1297).
See also: p1257 (Vdc_min controller speed threshold), p1297 (Vdc_min controller speed threshold (U/f))
F07406 (N, A) Drive: Kinetic buffering maximum time exceeded
Reaction: OFF3 (IASC/DCBRAKE, NONE, OFF1, OFF2, STOP2)
Acknowledge: IMMEDIATELY
Cause: The maximum buffer time (p1255 and p1295 for vector drives with U/f control) has been exceeded without the line
supply having returned.
Remedy: Check the time threshold for Vdc-min controller (kinetic buffering) (p1255, p1295).
See also: p1255 (Vdc_min controller time threshold), p1295 (Vdc_min controller time threshold (U/f))
A07409 Drive: U/f control, current limiting controller active
Reaction: NONE
Acknowledge: NONE
Cause: The current limiting controller of the U/f control was activated because the current limit was exceeded.
Remedy: The alarm automatically disappears after one of the following measures:
- increase current limit (p0640).
- reduce the load.
- slow down the ramp up to the setpoint speed.