Siemens SINUMERIK codes
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Siemens SINUMERIK Controller

Power Supply · Intermediate · 30-120 minutes

Alarm 300603

Siemens 840D 300603 - Axis, drive DC link voltage too high

Siemens SINAMICS drive alarm 300603: Axis, drive DC link voltage too high. The DC link voltage in the drive system is outside the acceptable range. This prevents safe drive operation.

Siemens SINUMERIKPower SupplyIntermediate30-120 minutes

300603

Siemens 840D 300603 - Axis, drive DC link voltage too high

Axis, drive DC link voltage too high

Siemens SINAMICS drive alarm 300603: Axis, drive DC link voltage too high. The DC link voltage in the drive system is outside the acceptable range. This prevents safe drive operation.

Safety

  • Refer to Siemens documentation
  • Ensure qualified technician performs repairs

Common Causes

  • Input AC supply voltage too high or too low
  • Regenerative braking energy not being dissipated properly
  • DC link capacitor failure in the drive unit
  • Line filter or reactor fault affecting supply quality
  • Load inertia too high causing excessive regeneration during deceleration

Troubleshooting Steps

  1. 1Measure the incoming AC supply voltage — verify all three phases are within specification.
  2. 2Check the braking resistor or regenerative unit if installed.
  3. 3Monitor DC link voltage in SINAMICS diagnostics during operation.
  4. 4Check for phase imbalance or missing phase on the AC supply.
  5. 5Contact Siemens service if DC link voltage is correct but the alarm persists.

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