| Abnormity of Current Detection | Circuit fault after current detection leads to abnormal current detection value |
|
ERR33 – Abnormal Current Detection
What this means
ERR33 indicates that the VFD is receiving invalid or unstable current readings from its internal current detection circuitry. Unlike load-related overcurrent errors, this fault means the measured current itself cannot be trusted.
In simple terms:
-
The VFD sees current values that do not make sense
-
The current detection signal is corrupted or unstable
-
The VFD shuts down to protect the motor and itself
This is not caused by feeds, speeds, or cutting load.
How ERR33 Is Different from ERR31
While ERR31 indicates a complete current detection failure, ERR33 means the detection circuit is working intermittently or reporting abnormal values.
Think of it as:
-
ERR31 = current detection is broken
-
ERR33 = current detection is present, but unreliable
Most Common Causes
1. Hall current sensor malfunction
The Hall-effect sensor used to measure motor current may be:
-
Aging
-
Producing noisy or unstable signals
-
Thermally stressed
This can result in fluctuating or incorrect current readings.
2. Driver board signal processing fault
After the Hall sensor, the signal passes through:
-
Amplifiers
-
Filters
-
ADC or logic stages on the driver board
A fault in this chain can distort the signal even if the sensor itself is functional.
3. Electrical noise or internal interference
Less common, but possible:
-
Internal grounding issues
-
Degraded shielding inside the VFD
-
Prior electrical events causing marginal components
This is internal to the VFD and not related to external cable shielding.
4. After-effects of previous faults
ERR33 may appear following:
-
Overcurrent events
-
Short-to-ground faults
-
Over-voltage or under-voltage incidents
Internal components may have been weakened but not fully failed.
What to Check First
Step 1: Fully power cycle the VFD
-
Turn off the VFD
-
Disconnect input power
-
Wait 2–3 minutes
-
Restore power and test again
If the error clears temporarily but returns, it strongly points to internal electronics degradation.
Step 2: Inspect motor and spindle cabling
Check for:
-
Physical damage
-
Crushed or pinched cable
-
Evidence of prior short events
Severe cable faults can stress current sensing components.
Step 3: Verify grounding
Ensure:
-
VFD ground is solid
-
Motor ground is intact
-
No floating grounds
Poor grounding can worsen signal instability but is rarely the root cause.
What Will Not Fix ERR33
-
Changing feeds or speeds
-
Adjusting acceleration or deceleration
-
Modifying torque curves
-
Re-running motor identification
ERR33 is not a tuning or configuration problem.
When to Contact Support
If ERR33:
-
Appears repeatedly
-
Occurs immediately at startup
-
Returns after clearing
-
Prevents reliable spindle operation
Please contact support with:
-
VFD model
-
Approximate age
-
Any recent faults or power events
-
Photos of wiring and grounding
In most cases, ERR33 indicates an internal VFD hardware issue requiring repair or replacement.
Summary
ERR33 means the VFD cannot reliably measure motor current.
Most common causes:
-
Hall sensor degradation
-
Driver board signal processing fault
-
Internal electrical damage from prior events
This is an internal electronics issue, not a user-operation issue.
