: Remove the external fault cause and then press the RESET button on the keypad or cycle the power.
: A failure in the external safety controller, emergency stop button, or safety relay providing the signals. cdn.prod.website-files.com Troubleshooting Steps Check Safety Inputs
Understanding and Resolving Yaskawa Error Code H66: Gate Drive Power Supply Faults
If you have exhausted all the steps above and H66 persists, professional intervention is needed. Contact Yaskawa support with the following ready:
The "Baseblock" status essentially means that the drive has cut off the power supply to the motor to prevent rotation. Unlike a standard software-based stop, the fault is triggered by the hardware safety inputs (usually terminals H1, H2, and HC). This feature is designed to provide a "Safe Torque Off" (STO) function, ensuring the motor cannot start unexpectedly during maintenance or an emergency. Primary Causes
: The fault can occur if there is a timing lag between the safety input signals (often labeled /HWBB1 and /HWBB2 ).
If the fault remains after basic checks, apply these advanced fixes.
To reset an H66 fault: