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Siemens SINUMERIK Controller
Servo/Axis · Intermediate · 30-120 minutes
Siemens 300782 - Axis drive reactance less than or equal to zero
This alarm occurs when the stator, rotor, or magnetizing reactance values in machine data (MD 1139, 1140, or 1141) are set to zero or negative, requiring correction of these parameters.
300782
Siemens 300782 - Axis drive reactance less than or equal to zero
Axis drive reactance less than or equal to zero
The value in MD 1139: $MD_STATOR_LEAKAGE_REACTANCE (stator leakage reactance) or MD 1140: $MD_ROTOR_LEAKAGE_REACTANCE (rotor leakage reactance) or MD 1141: $MD_MAGNETIZING_REACTANCE (magnetizing reactance) is less than or equal to zero. The alarm can be reprogrammed in the MD ALARM_REACTION_CHAN_NOREADY (channel not ready) Control reaction: NC not ready. The NC switches to follow-up mode. Channel not ready. NC Start disable in this channel. Interface signals are set. Alarm display. NC Stop on alarm. Channel not ready.
Root Cause Summary
This alarm occurs when the stator, rotor, or magnetizing reactance values in machine data (MD 1139, 1140, or 1141) are set to zero or negative, requiring correction of these parameters.
Safety
- Drive/power/encoder circuit: hazardous voltages may remain in the DC link after power-off. Lock out / tag out, wait for discharge per the drive documentation, and use qualified personnel only.
Causes and Fixes
- 1
Access machine data
Navigate to the machine data settings in the Siemens control panel.
- 2
Check reactance values
Verify the values in MD 1139 (stator leakage), MD 1140 (rotor leakage), and MD 1141 (magnetizing reactance).
- 3
Correct values
Set appropriate positive values as per motor specifications or consult the machine manual.
- 4
Reset and test
Save changes, reset the alarm, and test the system.
Call a technician if:
- ·If reactance values are unknown or unavailable in documentation
- ·If alarm persists after setting valid values
Prevention
- Ensure only qualified personnel perform commissioning
- Double-check motor data during commissioning
- Use manufacturer-provided values for reactance parameters
- Maintain proper documentation of all parameter changes
Common Mistakes
- Entering zero or negative values in machine data
- Overlooking motor-specific requirements in documentation
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