Why drives trip
A VFD trips to protect itself and your motor. The fault code tells you which protection acted — the job is to find out why, not just to reset it.
Overcurrent (OC)
Usually a short acceleration time, a jammed load, a motor or cable insulation fault, or a failing output stage. Check the load turns freely, megger the motor and cables, then lengthen the acceleration ramp.
Overvoltage (OV)
Mostly seen during deceleration of high-inertia loads, when the motor regenerates into the DC bus. Lengthen the deceleration ramp or add a braking resistor. High incoming supply can also cause it.
Undervoltage (UV)
Points to supply dips, a loose input connection, a blown input fuse or ageing DC bus capacitors. Log the supply voltage and inspect the capacitors for swelling.
Overheat (OH)
Blocked heatsinks, failed cooling fans or a hot panel. Clean the heatsink, replace fans and check panel ventilation before raising any limits.
Ground fault (GF)
Current leaking to earth — often damaged motor cable, water ingress in a junction box or a failing motor winding. Isolate and insulation-test before restarting.
When to call us
Repeat trips after a reset, burning smell, visible damage or an IGBT/power-module fault mean the drive needs bench diagnosis. MachiOn repairs ABB, Danfoss, Siemens, Schneider, Yaskawa, Delta and more.
