Schneider ATV630 OCF and SCF3 Faults: How to Separate Load and Output-Circuit Problems
Table of Contents
These are starting points for diagnosis. Neither code, by itself, proves that the drive needs replacement.
This guide covers these two faults on Altivar Process ATV630 drives. Record the complete drive reference and firmware version before applying instructions; other Altivar families have their own procedures.
OCF vs SCF3: What the Codes Tell You
| Code | Meaning | Investigation priority | What remains unproven |
|---|---|---|---|
| OCF | Overcurrent | Motor data, tuning consistency, excessive load or inertia, mechanical locking | Whether the problem is configuration, machinery or equipment sizing |
| SCF3 | Ground short circuit | Motor cable, insulation, output connections and long-cable installation | Whether the fault is in the cable, motor, connection or drive |
Schneider’s programming manual also lists high resistance at the motor connection among SCF3 causes. Do not limit the investigation to a visibly damaged cable. See the ATV600 Programming Manual, EAV64318.14, pages 672 and 678.
The checks below are a practical diagnostic framework based on Schneider’s guidance, rather than a manufacturer-prescribed test sequence.
Capture the Fault Evidence Before Resetting
On the graphic display terminal, open Diagnostics → Error history. Select the relevant fault and press OK to view the operating data captured with it. The history contains the last 15 detected errors; available records include motor current, output frequency and DC bus voltage.
Record:
- The exact code and the sequence of preceding faults.
- Whether it occurred at startup, during acceleration or after sustained operation.
- The operating values associated with the event.
- The motor nameplate and complete drive reference.
- Recent motor, cable, connection, process or parameter changes.
Keep observation separate from interpretation. “SCF3 appeared after a cable extension” is useful evidence. “The longer cable damaged the drive” is a conclusion that still requires investigation.
Where both OCF and SCF3 appear, preserve their order. An unresolved output-circuit concern should be assessed before attempting further powered load trials.
- Related Product
Need a Replacement Altivar Drive?
Browse new original Altivar drives for maintenance, troubleshooting, and replacement projects.
- New original parts
- Fast response
- Global shipping
Make the Equipment Safe Before Physical Checks
Reading the external display is different from opening the enclosure or touching wiring.
Before physical inspection, qualified personnel must isolate and lock out all power sources, including external control power, and prevent motor rotation. For the ATV630 covered by EAV64301.13, Schneider specifies a 15-minute discharge wait followed by verification of the absence of voltage. Waiting alone does not establish electrical safety.
Follow the full procedure in the ATV630/ATV650 Installation Manual, pages 8 and 17–18. Apply the machine’s isolation requirements to stored mechanical and process energy as well.
Investigating OCF: Separate Configuration from Mechanical Demand
Verify the installed motor against the saved settings
Schneider’s OCF guidance calls for checking motor-control parameters, nameplate information and whether the motor and drive can handle the application.
For an asynchronous motor, compare these basic settings with its nameplate:
| Parameter | Item to verify |
|---|---|
| nPr | Rated motor power |
| UnS | Rated motor voltage |
| nCr | Rated motor current |
| FrS | Rated motor frequency |
| nSP | Rated motor speed |
These parameter references are documented in Schneider’s ATV630 basic programming guidance.
The useful question is whether the configuration describes the motor currently connected. A replacement motor or an imported parameter file makes this comparison especially important.
Before changing settings, save the existing configuration and record the proposed correction. Retain a known, validated configuration for recovery; do not automatically restore values already shown to be wrong.
Use the timing to decide what to investigate next
| Observed pattern | Diagnostic question | Next step |
|---|---|---|
| OCF began after motor replacement or configuration download | Does the configuration match the installed motor? | Reconcile the nameplate, motor-control settings and commissioning records |
| OCF occurs during acceleration | Has starting demand changed? | Review load inertia, mechanical freedom and the application’s acceleration requirements |
| OCF occurs at an established operating point | What changed in the process or mechanism? | Compare current demand and process conditions with the last known acceptable operation |
| OCF persists after configuration and mechanical checks | Can the selected equipment meet the duty? | Have the motor/drive/load combination reassessed |
These patterns prioritize checks; they do not identify a failed component.
Inspect the mechanism under the machine builder’s safe maintenance procedure. A restriction or jam should be corrected before changing drive settings to accommodate it. Conversely, if the mechanism is satisfactory, document that finding so the investigation can move forward.
Treat autotuning as commissioning work
For asynchronous motors, Schneider’s getting-started instructions specify tuning with the motor cold and repeating tuning when motor parameters have been changed after a previous tune. Autotuning can move the motor, so qualified personnel must establish safe conditions before using it.
Do not trigger autotuning merely because OCF appears. First establish whether the motor data or tuning state actually requires correction.
- PLC Solutions
Find the Right PLC for Your System
Explore new original PLC CPUs, I/O modules, power supplies, and communication units for maintenance and automation projects.
- New original parts
- Fast response
- Global shipping
Investigating SCF3: Examine the Complete Output Circuit
Schneider’s SCF3 guidance identifies output short circuits or earth faults, motor/cable insulation problems and long-cable conditions. It also calls for checking grounding and, where appropriate, drive diagnostics.
Inspect connections as well as insulation
After safe isolation, have qualified personnel examine the route from the drive output to the motor terminal box.
Useful inspection targets include:
- Cable damage at glands, bends and entry points.
- Moisture, contamination or evidence of tracking.
- Damaged conductor insulation and stray strands.
- Deteriorated or poorly terminated motor connections.
- Protective-earth connections.
- Any intermediate terminal boxes, output switching devices or accessories.
These are inspection targets, not proof of a particular failure. Record where each defect was found and what corrective work was completed.
A satisfactory visual inspection also does not establish that the insulation is electrically sound.
Arrange appropriate motor and cable testing
Disconnect the drive from the motor circuit before insulation-resistance testing. Schneider explicitly requires this for testing motors or motor wires.
Have qualified personnel select the test method, voltage and acceptance criteria from the documentation applicable to the motor, cable and connected equipment. This article does not prescribe a universal insulation-test voltage or pass/fail resistance.
Request a report that identifies:
- Which components were included in each measurement.
- How the drive and other sensitive equipment were isolated.
- The procedure and acceptance criteria used.
- Whether the result identifies a component or only an affected circuit.
A failed measurement covering both motor and cable does not establish which one requires replacement. Further isolation and testing should follow an approved procedure.
Review long cables as an installation issue
Record the actual cable length, cable construction, shielding and installed output accessories.
Schneider’s installation manual explains that cable-related motor stress and permitted distance depend on motor insulation, cable type, installation arrangement and options. Its preventive measures differ by application.
Therefore, a long cable is a reason to review the installation—not sufficient evidence to order a particular reactor or filter. Have the proposed accessory checked against the exact drive, motor and cable arrangement.
Likewise, switching-frequency or ground-fault settings should not be changed experimentally to suppress SCF3. Any adjustment needs an application-specific reason and the applicable manufacturer instructions.
Turn the Findings into a Repair Decision
| Finding | Appropriate next action |
|---|---|
| Motor settings do not match the installed motor | Correct the configuration through controlled commissioning |
| A mechanical restriction or abnormal process demand is confirmed | Resolve the machine or process problem before further load testing |
| A cable or termination defect is identified | Repair the identified defect and complete the required electrical checks |
| Motor testing identifies an unacceptable condition | Obtain motor-service assessment using the documented results |
| Cable installation requirements are not met | Review the cable/accessory design before selecting components |
| The cause remains unresolved | Escalate with the fault history, configuration and inspection/test reports |
Escalation is particularly appropriate when SCF3 persists after the external circuit has been assessed, damage is visible, or the available evidence does not explain the trip. Drive diagnostics should then follow Schneider’s applicable procedure.
Do not improvise a powered test with disconnected motor leads or substitute components solely to see whether the code changes.
- HMI Replacement
Upgrade or Replace Your HMI
Find compatible HMI panels for discontinued models, machine upgrades, and operator interface replacement.
- New original parts
- Fast response
- Global shipping
Reset and Verify the Correction
For both OCF and SCF3, Schneider specifies a power reset after the cause has been removed. Repeated keypad resets are not the prescribed recovery method.
Before returning the equipment to service:
- Record the identified cause and corrective action.
- Confirm that wiring, grounding, covers and safeguards have been restored.
- Control run commands so power restoration cannot cause an unintended start.
- Perform the required reset and a supervised trial under the approved machine commissioning procedure.
- Check the operating condition associated with the original fault, where safe, and review the resulting current and fault records.
If the fault returns, preserve the new evidence and stop the reset cycle. A successful reset alone does not demonstrate that the underlying problem has been corrected.
Frequently Asked Questions
No. The result applies to the equipment included in the test and the conditions under which it was tested. A motor-only test does not establish the condition of the cable or intermediate connections.
Schneider also lists high resistance at the motor connection as a possible SCF3 cause. Review the test scope and connection checks before concluding that the drive is faulty.
Not necessarily. First compare the replacement motor’s nameplate with the drive configuration and check whether the stored tuning data corresponds to the connected motor. Schneider lists mismatched autotuned values among the possible OCF causes.
An equivalent power rating alone does not settle the diagnosis. If the configuration is correct, the next question is whether the motor and drive can meet the application’s load requirements.
Not before checking the extension and reviewing the complete installation. The timing makes the cable work a useful starting point, but it does not distinguish a connection defect, insulation problem or cable-related installation issue.
Filter requirements depend on the motor, cable type, length and drive arrangement. Have those details assessed before selecting an accessory; a filter should not be used to compensate for damaged wiring or an unresolved insulation fault.
Power your projects with brand-new, original Omron, Mitsubishi, Schneider Servo – in stock, ready now!
When Replacement Is Justified
Consider replacement when inspection, testing or manufacturer-supported diagnosis identifies a defective component, or when an application review establishes that the existing equipment cannot meet the required duty.
An OCF or SCF3 code alone is insufficient justification for buying a new drive. Replacing the drive while leaving an unresolved motor or cable problem in place does not complete the repair.
If diagnosis establishes a need for a replacement, contact Kwoco for part-number and sourcing assistance. Provide the complete ATV630 reference, motor nameplate, fault history, test findings and installed accessory details. Those records help define the enquiry; engineering approval of the replacement must still account for the actual application.
Contact Us
Just fill out your name, email address, and a brief description of your inquiry in this form. We will contact you within 24 hours.
Product Category
Hot Sale Products
Omron CPU Unit CJ2M-CPU32
Omron PLC CJ1W-PA202 Supplier in China
Mitsubishi MR-JE Series 400w Servo Drive MR-JE-40A
Need a Fast Match?
Share your model or spec and our team will help you find the right fit-fast.
- Expert support
- Quick response
- Competitive price
- +86-755-81481609
- [email protected]
You May Also Find These Topics Interesting
How to Verify Original Omron, Mitsubishi, Schneider Automation Parts
To verify original Omron, Mitsubishi and Schneider automation parts, check the supplier’s identity, establish the product’s traceability, inspect the delivered unit and
Contactor vs Relay: Understanding the Difference Between Contactors and Relays
This article dives deep into the world of contactors and relays, two essential components in industrial automation and control systems. We’ll explore their
How to Choose an Omron EtherCAT HMI and Motion Stack
Omron’s EtherCAT-based machine control ecosystem is attractive to modern builders because it is designed to connect motion, I/O, sensing, and related automation