| Module fault | External fault has triggered automatic module protection |
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ERR07 – Module Fault (Protection Triggered)
What this means
ERR07 indicates that the VFD’s internal power module protection has been triggered. This is a higher-level safety fault designed to protect the VFD from electrical damage when it detects abnormal conditions at the motor or output stage.
Unlike many other error codes, ERR07 is not caused by cutting parameters or normal load changes. It points to an electrical issue that the VFD considers potentially harmful.
Common Causes
1. Motor coil resistance abnormality
The VFD monitors current flow through the motor windings. If resistance is outside the expected range, the VFD assumes a fault condition.
Possible reasons:
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Damaged motor windings
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Loose or partially broken internal motor connections
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Connector issues at the spindle plug
2. Motor insulation breakdown
If current leaks from the motor windings to the spindle body or ground, the VFD will detect this as a dangerous condition.
This can be caused by:
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Moisture intrusion in water-cooled spindles
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Coolant leaks reaching electrical connections
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Damaged insulation inside the motor
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Contaminated or wet connectors
3. Output module protection event
The VFD’s internal inverter module can trip protection if it detects conditions that could lead to semiconductor damage.
Typical triggers:
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Short circuits at the motor output
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Incorrect wiring
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Severe electrical noise or grounding faults
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Prior repeated over-current or over-voltage events
What ERR07 Is Not
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Not caused by aggressive feeds or speeds
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Not a tuning or parameter issue
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Not a normal operational error
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Not something that can be fixed by adjusting acceleration or torque settings
Immediate Checks to Perform
Step 1: Power everything down
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Turn off the VFD
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Disconnect mains power
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Allow several minutes for internal capacitors to discharge
Step 2: Inspect motor and cable connections
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Check the spindle motor connector for bent pins, looseness, or contamination
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Verify the cable is not damaged, pinched, or abraded
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Ensure connectors are fully seated and locked
Step 3: Check for moisture or coolant intrusion
For water-cooled spindles:
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Inspect fittings and hose connections
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Check for signs of leakage near the spindle connector
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Ensure no coolant has reached electrical components
Step 4: Basic resistance and isolation checks (if equipped)
If you have a multimeter:
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Measure resistance between motor phases for consistency
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Check for continuity between motor phases and spindle body or ground
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There should be no continuity to ground
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If continuity to ground exists, do not continue operation.
If the Error Persists
ERR07 should not occur repeatedly. If it does:
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Do not continue attempting to run the spindle
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Repeated resets can worsen internal damage
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Contact support with:
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Photos of wiring and connectors
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Description of when the error occurs
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Any recent changes or incidents
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In rare cases, ERR07 can indicate damage to the VFD’s output module due to prior electrical events.
Summary
ERR07 is a serious protection fault indicating a potential electrical issue involving the motor, wiring, or VFD output stage.
Most commonly caused by:
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Motor insulation or wiring problems
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Moisture intrusion
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Electrical shorts or grounding faults
This error is not related to cutting parameters and should be addressed before further operation.
