In many factories, a sudden VFD trip can stop production instantly. Motors shut down, alarms appear, and operators panic. Understanding VFD trip fault codes helps engineers quickly identify the problem, reduce downtime, and protect expensive equipment. This practical guide explains common faults, real industrial causes, and step-by-step troubleshooting in simple language.
What Are VFD Trip Fault Codes?
A Variable Frequency Drive (VFD) controls motor speed and torque. But when something goes wrong-like overload, voltage fluctuation, overheating, or short circuit-the drive protects itself and the motor by tripping.
These protective shutdown signals are called VFD trip fault codes.
Each code represents a specific issue, such as:
- Overcurrent (OC)
- Overvoltage (OV)
- Undervoltage (UV)
- Overload (OL)
- Overheat (OH)
- Earth fault (GF)
- DC bus overvoltage fault
Instead of guessing, these fault codes give a clear starting point for VFD fault diagnosis and troubleshooting.
Why Does a VFD Trip Frequently?
Before jumping into specific errors, let’s understand a common question:
Why does VFD trip frequently?
In real industrial conditions, drives trip because of:
- Improper parameter settings
- Heavy or sudden load changes
- Poor cable termination
- Voltage fluctuations
- Inadequate cooling
- Grounding issues
- Incorrect motor sizing
When technicians ignore early warning signs, small problems turn into repeated VFD motor tripping problems.
Most Common VFD Trip Fault Codes Comparison and Their Meaning
Below is a simplified comparison table that helps engineers quickly understand common issues.
| Fault Code | Meaning | Common Cause | Immediate Action |
| OC | Overcurrent fault in VFD | Short circuit, sudden load | Check motor & wiring |
| OV | Overvoltage trip in VFD | High input voltage, regen energy | Check supply & braking |
| UV | Undervoltage error in VFD | Low voltage supply | Inspect power source |
| OL | Overload fault in VFD | Motor overload | Check load condition |
| OH | Overheat trip | Poor ventilation | Clean cooling fans |
| GF | Earth fault in VFD | Insulation failure | Check grounding |
Now let’s explain each in detail.
1. Overcurrent (OC) Fault in VFD
One of the most searched questions is:
What causes VFD overcurrent fault?
An overcurrent fault occurs when motor current exceeds safe limits. This can happen:
- During startup
- When motor shaft is jammed
- Due to short circuit in cables
- Improper acceleration time
- Incorrect VFD protection parameters
Why VFD Trips During Startup?
If acceleration time is too short, the motor draws excessive current. This leads to VFD trip when motor starts problem.
How to Fix It
- Increase acceleration ramp time
- Check motor insulation
- Inspect load condition
- Verify current rating
In many industrial VFD troubleshooting cases, simply adjusting parameters reduces unnecessary trips.
2. Overvoltage (OV) Fault
How to fix VFD overvoltage error?
An overvoltage trip in VFD happens when DC bus voltage becomes too high.
Common reasons:
- Sudden deceleration
- Regenerative load (like elevators or conveyors)
- Unstable power supply
- Improper braking resistor
When motors stop suddenly, energy flows back to the drive, causing DC bus overvoltage fault.
Solution
- Increase deceleration time
- Install braking resistor
- Check supply voltage
- Inspect panel grounding
3. Undervoltage (UV) Error
Low voltage is common in many industrial areas.
Why is my VFD showing undervoltage error?
Possible reasons:
- Weak transformer
- Loose input terminals
- Generator instability
- Long cable runs
Undervoltage reduces torque and increases heating. If ignored, it may cause motor overheat trip later.
4. Overload (OL) Fault in VFD
What is OL fault in VFD?
Overload fault in VFD means the motor is running beyond rated capacity for a longer time.
Causes include:
- Mechanical blockage
- Oversized production demand
- Incorrect motor selection
- Poor maintenance
If a drive shows repeated overload fault in VFD, check mechanical load before resetting.
5. Overheat (OH) Fault
What is OH fault in VFD?
This fault indicates overheating inside the drive panel.
Common causes:
- Dust accumulation
- Cooling fan failure
- High ambient temperature
- Improper panel ventilation
In India, especially during summer, this is one of the top reasons for VFD drive failure reasons.
Preventive Tip
Regular cleaning and structured VFD panel maintenance reduces long-term drive failures and overheating risks.
How to Troubleshoot VFD Trip Fault Codes (Step-by-Step)
When facing repeated VFD trip fault codes, follow this structured approach:
Step 1: Note the Fault Code
Do not immediately reset. Understand the VFD alarm codes meaning.
Step 2: Check Power Supply
Measure voltage stability.
Step 3: Inspect Motor and Cable
Look for damage, loose terminals, or grounding issues.
Step 4: Review Parameters
Verify VFD protection parameters and ramp settings.
Step 5: Check Load Condition
Mechanical problems often cause electrical trips.
Step 6: Reset and Test
After correction, perform controlled restart.
This systematic approach improves Industrial VFD troubleshooting efficiency, especially when supported by professional service experts.
How to Prevent Frequent VFD Tripping in Factory
Prevention is better than emergency repair.
Here’s how to reduce VFD tripping in factory:
- Proper motor sizing
- Correct parameter configuration
- Regular insulation testing
- Clean control panels
- Install surge protection
- Monitor load pattern
Many industries now use predictive maintenance to avoid unexpected downtime.
Pros and Cons of VFD Protection Trips
Pros
- Protects motor from burning
- Prevents cable damage
- Reduces fire risk
- Saves repair cost
Cons
- Causes production downtime
- Requires technical understanding
- May interrupt critical processes
Overall, trip faults are protective features, not disadvantages.
Real Industrial Example
In one manufacturing plant, operators reported that VFD trips during heavy load every week. Initially, they blamed the drive.
However, after analysis, the real issue was mechanical misalignment. Once corrected, VFD trip fault codes stopped appearing.
This shows that not every trip is an electrical fault-sometimes it’s a mechanical issue.
When to Call a Professional VFD Service Provider?
Sometimes incorrect parameters cause repeated trips, and in such cases a professional VFD programming service can solve the issue permanently.
You should contact a professional if:
- VFD trips repeatedly even after reset
- Drive shows multiple alarm codes
- Burn smell or visible damage
- Parameter corruption
- Control panel overheating
Searching for:
- VFD repair service in India
- Industrial VFD troubleshooting service
- VFD panel service provider
- VFD maintenance company
can help find experienced automation experts.
VFD Service in Bhopal & Madhya Pradesh
If your factory is located in central India, finding a reliable VFD repair service in Bhopal or VFD troubleshooting service Bhopal is important.
Local industrial automation company in Bhopal can:
- Diagnose drive protection system issues
- Provide PLC and VFD service provider support
- Handle VFD programming service
- Offer AMC for preventive maintenance
Working with a nearby control panel manufacturer in Bhopal ensures faster response time and better technical understanding.
Quick FAQ Section
What is the OC fault in VFD?
OC fault means overcurrent fault. It occurs due to short circuit, sudden load, or improper acceleration settings.
How to reset VFD after a trip?
First fix the root cause. Then use the reset button or power cycle. Never reset repeatedly without checking.
Why does VFD trip during startup?
Because of high inrush current, short ramp time, or mechanical blockage.
What is the difference between OC and OL fault in VFD?
OC is a sudden current spike. OL is a prolonged overload condition.
Safety and Practical Use-Case Analysis
Understanding VFD trip fault codes is not just technical knowledge. It directly affects:
- Production uptime
- Equipment lifespan
- Energy efficiency
- Safety compliance
Improper handling can damage motors, cables, and even transformers.
Therefore:
- Always follow lockout-tagout procedures
- Use proper testing instruments
- Keep documentation of fault history
- Train technicians regularly
Final Thoughts
In industrial automation, downtime is costly. But when engineers understand VFD trip fault codes, they can quickly identify problems and prevent major breakdowns.
Instead of randomly resetting drives, analyze fault patterns, review parameters, and inspect mechanical load. A structured troubleshooting approach builds trust in your system and reduces panic on the shop floor.
Whether you manage a small factory or a large production plant, knowing the meaning behind VFD alarm codes helps you maintain reliability, safety, and efficiency.
