Many equipment maintenance technicians often encounter motor faults such as abnormal operating noise, difficulty starting, or even complete failure to run. Based on years of after-sale service experience of dc planetary gear motor , I have compiled a step-by-step inspection process that you can quickly locates root causes without resorting to blind disassembly.
All inspections follow the standard that you are advised to test power supply under power first, then perform maintenance after power cut.
You are advised to measure power supply parameters with full insulation protection throughout the process in a short time when the equipment is on and do not touch exposed live terminals. Immediately cut off the main power supply, lock out and tag the power switch after testing, then carry out subsequent disassembly, shaft turning and winding inspection work.
Phase 1: Inspect Power Supply and Control Circuit
Use a multimeter under power to measure three-phase voltage checking for phase loss or insufficient voltage. Meanwhile, examine the AC contactor for issues such as such as contact erosion or coil engagement failure. Loose terminals and wrong wiring also lead to abnormal power supply which directly affects motor startup.
Phase 2: Troubleshoot Mechanical Faults (After Power Cut, Lockout & Tagout)
If resistance, sticking, or friction noises are detected while turning, the cause is likely bearing wear which lacks lubrication, or the presence of foreign matter.If the shaft cannot rotate at all, the load is likely seized or transmission parts are misaligned and jammed. Such mechanical defects will generate obvious abnormal noise during operation.
Phase 3: Test Motor Windings
If no issues are found in power supply and mechanical parts,professional tools including multimeter and megohmmeter are used to check whether three-phase winding resistances are balanced, detect open circuits and inter-turn short circuits, measure winding insulation to ground verifying correct connection of winding start and end leads.
In addition,a reminder is for you that do not repeatedly force-start the faulty motor. Continuous power supply under phase loss or winding short circuit conditions will easily burn out the coils and cause further damage. Following this step-by-step troubleshooting sequence improves efficiency and helps minimize unnecessary repair costs.