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Why the spindle motor stop running?
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When the spindle of a CNC machine tool suddenly stopped rotating during operation, maintenance personnel performed the following troubleshooting steps:
Initial Assessment: Upon startup, the variable frequency drive's (VFD) forward-run relay engaged and the indicator light illuminated (indicating a valid run command), yet the spindle remained stationary. Based on the characteristics of analog control, the issue was diagnosed as a missing analog signal (the 0–10V speed command).
VFD-Side Check: A multimeter measurement at the VFD's analog input terminals (red/black wires) showed only 2.6 mV—an invalid voltage level—confirming that the signal was not reaching the VFD.
Tracing System Output: Measurements taken at the corresponding output terminals of the CNC system board also showed only approximately 2.6 V, indicating that the system board was failing to output the analog signal.
Conclusion and Resolution: The issue was not caused by external wiring (as a wiring fault would still require an output from the system side) but rather by an internal failure of the system board (e.g., a damaged chip or component). As on-site repair was not possible, the board had to be removed and sent to the manufacturer for testing and inspection.
Paycnc offers all kinds of cnc machine spare parts.
If you could not find the exact model, you can send item photo and its nameplate to paycnc@paycnc.com to get quotation.
When the spindle of a CNC machine tool suddenly stopped rotating during operation, maintenance personnel performed the following troubleshooting steps:
Initial Assessment: Upon startup, the variable frequency drive's (VFD) forward-run relay engaged and the indicator light illuminated (indicating a valid run command), yet the spindle remained stationary. Based on the characteristics of analog control, the issue was diagnosed as a missing analog signal (the 0–10V speed command).
VFD-Side Check: A multimeter measurement at the VFD's analog input terminals (red/black wires) showed only 2.6 mV—an invalid voltage level—confirming that the signal was not reaching the VFD.
Tracing System Output: Measurements taken at the corresponding output terminals of the CNC system board also showed only approximately 2.6 V, indicating that the system board was failing to output the analog signal.
Conclusion and Resolution: The issue was not caused by external wiring (as a wiring fault would still require an output from the system side) but rather by an internal failure of the system board (e.g., a damaged chip or component). As on-site repair was not possible, the board had to be removed and sent to the manufacturer for testing and inspection.
Paycnc offers all kinds of cnc machine spare parts.
If you could not find the exact model, you can send item photo and its nameplate to paycnc@paycnc.com to get quotation.
