Siemens 6RA70 specifications Fault Description

Fault	Description
No.	Cause as a function of fault value	Further information (r047.002 to r047.016)
	(r047.001, r949.001 or r949.009 with acknowledged error)
3	Armature current peaks are too small at α=30° and EMF=0
	(armature current peak value <50% of IA, motor or <50% of IA,rated)
	Possible cause:
	• Armature circuit inductance is too high (field supply from armature terminals)
	• P150 (Alpha G limit) has been set to excessively high value
	Possible remedy:
	• Reduce P100 (IA,motor) while this optimization run is in progress

4The armature circuit inductance (P111) cannot be determined from the sampled values of the armature current and line voltage of the armature current crest last generated

Possible cause:

•P100 (IA,motor) or r072.i002 (IA,rated) very much smaller than actual motor rated current of the armature

•LA >327.67mH (armature circuit inductance too large)

•P100 (IA,motor) very much smaller than r072.i002 (IA,rated)

•Armature circuit short-circuited

5Offset adjustment of actual field current sensing is not possible (value detected for P825 is outside permissible value range) Possible cause:

•Fault in actual field current sensing circuit

(defective A7004 gating board or A7001 electronics board)

7The field circuit resistance (P112) is indeterminable

(the actual field current does not reach the internally specified setpoint of 95% of P102 as a result of P112 variation) Possible cause:

•RA >3276.7Ω

•Fault in actual field current sensing circuit (defective gating board or A7001 electronics board)

•The command “Inject standstill field” is applied

•P102 is set too high

•A thyristor in the field bridge is not firing

880% of rated EMF (K287=P101 – P100 * P110) cannot be reached within 15s (or maximum of the three set acceleration times)

Possible cause:

•Acceleration time (P303, P307, P311) is set too low

•P101 does not match the set maximum speed (UA at nmax < P101) or setting for P102 is too low

•The command “Ramp-function generator enable”=0 or ”Ramp-function generator stop”=1

9Field current control loop is not stable enough to record field characteristics

(30s after injection of internal field current setpoint, actual field current is deviating by more than (0.39% of P102 + 0.15 % of r073.002) from the setpoint)

Possible cause:

•Field current controller or field current precontrol is not optimized or optimized badly (check P112, P253 to P256 or execute a current controller optimization run (P051=25))

10Field characteristic is not uniform

(i.e. in spite of field current setpoint reduction, the flux values of this measuring point calculated from EMF and actual speed are rising)

Possible cause:

•High armature reaction and sharp load variations during recording of field characteristics

•Field current controller or field current precontrol is not optimized or optimized badly (check P112, P253 to P256 or execute a current controller optimization run (P051=25))

11A lower field current limit of ≥ 50% of P102 (IF,motor) is applied

(for this reason, it is not possible to plot a minimum of 9 field weakening measuring points) Possible cause:

•P103 ≥ 50% of P102 Check P614 !

Siemens Energy & Automation	9-15
SIMOREG DC Master Base Drive Panel	Operating Instructions