Fanuc alarm HV: Overvoltage alarm (LED legend)
βi SVU/SVM · Fanuc βi SVU/SVM
What it means
On β-series servo units (SVU, e.g. A06B-6093) there is no numeric 7-segment display; instead the labeled legend LED 'HV' lights on the unit when DC link voltage rises abnormally high. Commonly triggered during regeneration into insufficient absorption capacity.
Likely causes
- Missing or undersized external regenerative resistor
- Excessive deceleration energy from high-inertia axes
- Supply voltage spikes / SVU internal voltage detection failure
Triage note: Fault mnemonic also reported on the CNC servo tuning/diagnosis screen.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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External regenerative resistor (per SVU spec)
amplifier · Primary suspect
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A06B-6093-Hxxx (SVU, match model)
amplifier · Check if others ruled out
Need the part urgently?
Send us alarm HV with your machine details — typical RFQ turnaround is 24–48h.