Yaskawa Sigma-5 & Sigma-7 Diagnostics
Yaskawa drives are common in high-precision motion control applications. This guide explains how to troubleshoot key alarms.
1. Alarm A.100 - Overcurrent or Heat Sink Overtemperature
The drive has detected high current or heatsink temperatures. Causes: Output short circuit, motor grounding fault, or damaged power stage. Action: Check motor insulation, perform static diode tests, and replace faulty IGBTs and driver components.
2. Alarm A.C90 - Encoder Communications Error
Serial communication with the motor encoder has been lost. Causes: Faulty encoder cables or a failure in the drive's line receiver circuit. Action: Verify cable shielding, check the 5V supply, and replace damaged transceiver ICs on the drive's control board.