Unstable voltage at the brake coil can create a cascade of issues. If voltage dips, an electromagnetic brake may not fully release, causing dragging, heat buildup, and rapid lining wear. If voltage spikes or is continuously too high, the coil can overheat, degrade insulation, and eventually burn out. Fluctuation can also cause chatter—rapid partial engage/release—which accelerates mechanical wear and produces inconsistent braking torque.
On cranes with VFDs, voltage instability may come from wiring errors, inadequate control power design, poor contactor/relay condition, or long cable runs causing voltage drop. Symptoms include buzzing, delayed release, hot brake housings, and increased motor current. The best practice is to measure voltage at the brake terminals during operation (not just at the panel), verify rectifier sizing, and ensure proper grounding and surge suppression. Stable coil voltage is not “electrical detail”—it directly impacts crane brake safety and uptime.