VFD-rated motor cable
Price this when overcurrent or overload faults trace to damaged output wiring.
Fanuc Alarm 460 — What It Means
Alarm 460 on a Fanuc CNC means the spindle load exceeded the permissible limit. This can happen because of an aggressive cut, dull tooling, a seized spindle component, or a problem in the spindle drive system.
Common Causes
- Tool is dull or chipped. Cutting force rises sharply and drives spindle load up.
- Feed or depth of cut is too aggressive. The program is demanding more torque than the spindle can safely deliver.
- Spindle bearings are failing. Heat and drag increase spindle motor current.
- Gearbox or belt drive problem. Mechanical drag upstream of the spindle creates overload.
- Spindle drive or cooling issue. An overheated drive can behave unpredictably and trip load alarms.
Step-by-Step Fix
- Check the tool first. Replace dull or damaged tooling before chasing electrical faults.
- Reduce feed and depth of cut. If the alarm disappears, the issue is process load, not machine failure.
- Run the spindle unloaded at several RPMs. If load is high with no tool cutting, the issue is mechanical or electrical.
- Listen for bearing noise. Growling, heat, or vibration points to spindle bearing failure.
- Inspect belts or gearbox if equipped. A seized idler or tight gearbox raises load dramatically.
- Check spindle drive cooling. Dirty filters or failed cooling fans can cause drive overheating and nuisance overload trips.
Parts Often Needed
| Part | Notes |
|---|---|
| Spindle bearings | Replace if heat or noise is present |
| Toolholder / cutting tool | Dull tools are the simplest fix |
| Drive cooling fan | Check spindle drive cabinet airflow |
| Belt set | Replace if glazed, cracked, or over-tensioned |
Technician Tips
CNC alarms should always be diagnosed by reading the full alarm text, not just the number. Modern Fanuc, Haas, and Mazak controls provide detailed alarm descriptions — press the help key while viewing the alarm for diagnostic suggestions. The alarm history screen stores the last 50-100 alarms with timestamps; review this before clearing to identify patterns. A servo alarm (SV series on Fanuc) that appears only during rapid traverse points to a different cause than one that appears during cutting.
Prevention: Back up your CNC parameters monthly. Battery-backed memory faults are much easier to recover when you have a current parameter, ladder, offset, and macro backup. Replace control batteries on a planned maintenance schedule before voltage drops far enough to risk data loss.
Need Replacement Parts?
Before ordering, match the machine-control part to the model number, electrical rating, and failure symptom. Check current prices on Amazon - prices and availability change frequently.
When to Call a Pro
If spindle load is high with no cutting load, the machine likely needs spindle service, drive diagnostics, or both. Continuing to run it risks spindle damage.