| Contactor | Abnormal power supply of driver board caused by the fault of the contactor |
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ERR32 – Contactor / Driver Board Power Supply Fault
What this means
ERR32 indicates that the VFD has detected an abnormal power condition feeding the internal driver board, most commonly related to the contactor or the internal control power supply.
In simple terms:
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The VFD’s control electronics are not receiving stable power
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The VFD cannot safely drive the motor
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The unit shuts down to prevent damage
This is not a cutting load or spindle issue.
What Causes ERR32
1. Internal contactor fault
Some VFDs use an internal contactor or relay to manage:
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Power sequencing
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Control board enable/disable
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Safety interlocks
If that contactor:
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Fails
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Does not fully engage
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Has worn or pitted contacts
The driver board will not receive proper voltage and ERR32 is triggered.
2. Internal control power supply instability
The driver board runs off an internal low-voltage supply derived from the main input.
ERR32 may occur if:
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The internal supply is unstable
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Capacitors are aging or failing
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A regulator is dropping out under load
This is typically age-related or caused by electrical stress.
3. Incoming power quality issues
External conditions that can contribute:
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Momentary brownouts
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Voltage dips
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Loose mains connections
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Poor-quality power at startup
Even brief interruptions can prevent the driver board from powering correctly.
4. Loose or damaged internal connections
Less common, but possible:
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Internal wiring loosened during shipping
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Vibration over time
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Prior overheating events
What to Check First
Step 1: Fully power down the VFD
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Turn off the VFD
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Disconnect input power completely
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Wait 2–3 minutes for internal capacitors to discharge
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Restore power and test again
If ERR32 clears and does not return, it may have been a transient power event.
Step 2: Verify incoming power stability
Check:
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Input voltage matches the VFD rating
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No loose terminals at the mains input
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No shared circuits with high-load equipment if possible
Power dips at startup are a common trigger.
Step 3: Observe when the fault occurs
Note whether ERR32 appears:
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Immediately at power-up
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After sitting powered on
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During spindle start
This timing helps distinguish between contactor issues and power supply instability.
What Will Not Fix ERR32
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Changing feeds or speeds
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Adjusting acceleration or deceleration
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Re-running motor identification
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Changing spindle parameters
ERR32 is not related to motor load or cutting conditions.
When to Contact Support
If ERR32:
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Occurs consistently
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Appears immediately on every power-up
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Returns after power cycling
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Prevents the VFD from staying powered
Please contact support with:
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VFD model
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Input voltage
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Approximate age
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When the fault appears
In many cases, ERR32 indicates an internal hardware issue that may require repair or replacement.
Summary
ERR32 means the VFD’s driver board is not receiving stable internal power.
Most common causes:
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Internal contactor failure
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Control power supply instability
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Power quality issues
This is an internal electronics fault, not a spindle, toolpath, or tuning problem.
