Error 607 is fundamentally a communication error between the drive and the power switching device. In 80% of cases, the root cause is a failed contactor coil, a loose wire, or a dirty auxiliary contact. By observing whether the contactor physically engages, the technician can quickly narrow the focus between a power output issue (contactor side) or a feedback input issue (drive side).

: High-resistance connections due to loose screws on the DC link can prevent stable current flow. Troubleshooting Steps

The braking resistor was undersized for the duty cycle. Upgrading to a higher-wattage resistor with a more robust thermal mass—and adding an external fan—solved the issue permanently.