| Motor Off-Load | Refer to the value of running current less than off-load current P6.0.18 and duration of P4.0.19 |
|
ERR19 – Motor Off-Load Detected
What this means
ERR19 indicates that the VFD has detected a motor off-load condition.
In simple terms, the VFD believes the spindle is running with too little load for a specified amount of time.
This is a protection feature intended to detect situations where the motor may be:
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Disconnected
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Spinning freely without expected resistance
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Operating outside normal load conditions
Why This Happens
The VFD monitors motor current during operation.
If the measured current drops below a configured off-load threshold for longer than the allowed duration, the VFD assumes something is wrong and triggers ERR19.
This fault is based on logic and thresholds, not a physical failure.
Most Common Causes We See
1. Off-load protection enabled too aggressively (most common)
The off-load current threshold or duration may be set too sensitive for CNC spindle use.
CNC spindles often:
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Run unloaded during tool changes
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Spin freely during rapids
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Have light loads during finishing passes
If the VFD expects heavier load, ERR19 can trigger incorrectly.
2. Spindle running unloaded for extended periods
Examples:
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Long warm-up cycles at high RPM
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Spindle left running without cutting
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Tool changes or probing routines
If current stays below the off-load threshold long enough, ERR19 may occur.
3. Incorrect off-load current settings
Parameters controlling off-load detection may not be appropriate for:
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Small tools
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Light materials
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Finishing passes
4. Motor or cable intermittently disconnected (less common)
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Loose motor connector
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Intermittent cable fault
This can cause sudden drops in current that look like off-load conditions.
What to Check First
Step 1: Review off-load detection parameters
Check:
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P6.0.18 – Off-load current threshold
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P4.0.19 – Off-load duration time
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P6.1.19 / P6.1.20 – Related off-load protection parameters
If these values are set too high or too short, false ERR19 faults are likely.
Step 2: Consider your workflow
Ask:
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Does the spindle run unloaded for long periods?
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Are light finishing passes common?
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Is the spindle left running between operations?
If yes, off-load protection may need adjustment or disabling.
Step 3: Inspect motor wiring (basic check)
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Verify motor connector is fully seated
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Check for intermittent connection issues
This is a sanity check, not the usual cause.
What ERR19 Is Not
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Not an over-current fault
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Not a voltage issue
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Not a cutting aggressiveness problem
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Not EMI related
ERR19 is about too little load, not too much.
Recommended Action for CNC Use
For most CNC spindle applications:
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Off-load protection is not critical
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Many users choose to relax or disable this feature to prevent nuisance faults
Any changes should be made carefully and documented.
If unsure, contact support before making adjustments.
When to Contact Support
If:
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ERR19 occurs frequently
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You are unsure which parameters to adjust
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The fault appears intermittently during normal operation
Support can help determine whether off-load protection should be tuned or disabled for your use case.
Summary
ERR19 means the VFD believes the spindle is running with insufficient load for too long.
Most common causes:
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Overly sensitive off-load detection settings
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Extended unloaded spindle operation
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Light cutting conditions
This is typically a configuration issue, not a hardware failure.
