4159

Common Causes

• Inverter unit deteriorated or mis-sized for the load
• Mechanical overload: tight ballscrew, binding way, or heavy cut on the named axis
• Motor or wiring problem drawing excess current

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code YYYY (first half) = Gamma of the protection curve used to detect the overload; code ZZZZ (second half) = Internally calculated overload data showing how far the limit was exceeded
2. 2Read the code on screen: the first half is the gamma of the protection curve used and the second half is the internally calculated overload value, which tells how far past the limit the load went.
3. 3Reduce cutting load on the named axis (lighter depth of cut, lower feedrate) and see whether the alarm stays away, which would confirm genuine overload operation.
4. 4With the machine at rest, move the axis by hand or watch its load meter during a slow jog to check for binding, a failing bearing, or way-lube starvation adding mechanical drag.
5. 5Lock out and discharge the DC bus before opening the cabinet, then check motor power cables and connectors for heat damage or looseness.
6. 6If the overload value is high even with a free-moving axis and light program load, the inverter unit itself is suspect and should be evaluated for replacement.