axismd.ai
Okuma OSP Controller
Power Supply · Intermediate
Okuma OSP Alarm A 1158 - MCS Power unit overheat
The inverter (power) unit for the indicated axis or spindle has exceeded its normal temperature. This is usually caused by sustained overload operation or a failing inverter unit.
1158
Okuma OSP Alarm A 1158 - MCS Power unit overheat
MCS Power unit overheat
The inverter (power) unit for the indicated axis or spindle has exceeded its normal temperature. This is usually caused by sustained overload operation or a failing inverter unit.
Common Causes
- Inverter unit internal fault or failed cooling
- Prolonged overload operation (heavy cutting, high duty cycle)
Troubleshooting Steps
- 1Read the code number shown with the alarm: code 1 = Fixed code; inverter unit temperature abnormally high
- 2Note which axis or spindle is named in the Object field, then power down and allow the inverter unit to cool before restarting.
- 3Check the inverter unit's cooling: fan operation, blocked vents, and heat sink contamination in the electrical cabinet.
- 4Review the recent cutting load; if the machine was running heavy continuous cuts, lighten the load and monitor whether the alarm recurs.
- 5Lock out power and observe capacitor discharge precautions before opening the drive cabinet to inspect the inverter unit.
- 6If cooling is clean and loads are normal but the alarm returns, the inverter unit itself is likely faulty; record the alarm and object and contact Okuma service.
Seeing Multiple Alarms?
Seeing another alarm with this one? Enter the code.
Get machine-aware diagnosis
AxisMD logs alarms against your actual machines, tracks patterns, and gives AI context your manual doesn't have.
Start freeWas this guide helpful?
Always verify with your machine manual or a certified technician before performing service procedures.