Siemens 6RA70 specifications Fault Description

Fault

No.

Description
Cause as a function of fault value	Further information (r047.002 to r047.016)
(r047.001, r949.001 or r949.009 with acknowledged error)

20 Current limit is too low

(With speed controller optimization run: Less than 30% or 45% of P100 (IA,motor) + the armature current required for zero speed,

With optimization run for friction moment and moment of inertia compensation: Less than 20% of P100 (IA, motor) + the armature current required for a steady-state speed corresponding to 10% of maximum speed)

21 Field weakening range is too wide (nact < +7% nmax produces EMF > 54% setpoint EMF) (setpoint EMF= K289= P101 – P100 * P110)

Possible cause:

•Maximum speed setting is incorrect

•Pulse encoder parameters are incorrect (P140 to P143)

•Parameters for tachometer adaptation are incorrect (P741)

•Setpoint EMF is not correct (P101, P100, P110)

•Caution:

Even a high absolute negative actual speed value can produce an EMF of > 54% setpoint EMF

22With speed controller optimization run:

With an acceleration current equaling 20% or 30% of P100 (IA, motor) + armature current required for zero speed or With optimization run for friction moment and moment of inertia compensation:

With an acceleration current equaling the current required to achieve a steady-state speed of 10% of maximum speed + 20% of P100 (IA, motor), the maximum speed cannot be reached within 45s +7%

Possible cause:

•Centrifugal mass is too large

•Drive is blocked, heavily speed-dependent or excessively high load torque

•“Active” load is attempting to maintain a certain speed

Possible remedy:

•Increase P100 while the optimization run is in progress in order to raise the applied acceleration current during optimization (during the speed controller optimization run, a maximum of 45% of IA, motor (+ armature current for zero speed) is applied as the armature current setpoint, IA,motor (P100) can thus be increased to 2.2 times the value at maximum without exceeding 100% IA, motor during optimization)

23With speed controller optimization run:

With an acceleration current equaling 20% or 30% of P100 (IA, motor) + armature current required for zero speed or With optimization run for friction moment and moment of inertia compensation:

With an acceleration current equalling the current required to achieve a steady-state speed of 10% of maximum speed + 20% of P100 (IA, motor), the maximum speed or 100% of setpoint EMF cannot be reached within 90s +13%

Possible cause:

•Flywheel mass is too large

•Drive is blocked, heavily speed-dependent or excessively high load torque

•“Active” load is attempting to maintain a certain speed

Possible remedy:

•Increase P100 while the optimization run is in progress in order to raise the applied acceleration current during optimization (during the speed controller optimization run, a maximum of 45% of IA, motor (+ armature current for zero speed) is applied as the armature current setpoint, IA,motor (P100) can thus be increased to 2.2 times the value at maximum without exceeding 100% IA, motor during optimization)

24With speed controller optimization run:

The actual speed does not drop to below +2% of maximum speed or to below the speed threshold nmin set in P370 within 2 minutes

With optimization run for field weakening:

The actual speed does not drop to below +2% of maximum speed or to below the speed threshold nmin set in P370 within 10 minutes

With optimization run for friction moment and moment of inertia compensation:

The actual speed does not drop to below +2% of maximum speed or to below the speed threshold nmin set in P370 within 11 or 2 minutes

Possible cause:

• Single-quadrant drive coasts to a standstill too slowly

Siemens Energy & Automation	9-17
SIMOREG DC Master Base Drive Panel	Operating Instructions