What is VFD tripping on overcurrent? When a frequency converter senses an excessive current flow, it trips, preventing harm by initiating a preventive shutdown. Finding the underlying causes of such accidents is made possible in large part by fault analysis. Operators can preserve system effectiveness, minimize downtime, and guarantee the lifespan of vital equipment by identifying these issues.
What is VFD tripping on overcurrent?
VFD tripping on overcurrent happens when a variable frequency drive (VFD) trips on overcurrent. It indicates that an excessive current flow has been recognized by the drive’s protection circuit, which causes it to cut off to safeguard the motor and itself.
This usually occurs when the motor consumes more current than it is intended to, which can happen for several reasons, such as overload, short circuits, or improper drive settings.
Common Causes of VFD Overcurrent Tripping
Do you have a variable-frequency drive in use? An overcurrent problem can result from a variety of factors that affect the interaction between your VFD and motor.
Typical Situations that Cause VFD Overcurrent Faults:
- An abrupt rise in the current draw can occur when a motor is mechanically seized or struck from the front.
- The output of the VFD can be short. For instance, there may be a short inside the motor or an issue with the motor cord.
- Deterioration of internal components may be the cause of an aberrant driving operation.
Types of Overcurrent Faults in VFD Systems
VFD tripping on overcurrent faults can be broadly divided into three types:
1- Overload:
This happens when the motor and VFD’s rated current is exceeded, but not to the point of a short circuit. Inadequate supply voltage, poor VFD settings (such as inappropriate motor specifications), or an excessive load on the motor are among the causes. VFD tripping and possible motor overheating are among the symptoms
2- Circuit Short:
Involves two conductors connected by a low resistance, which frequently results in a significant current surge. May take place inside the VFD itself, the wiring, or the motor windings. Causes an extremely high current flow, which might harm the motor and VFD.
3-The ground fault
occurs when insulation failure or other grounding problems cause current to flow to ground. May be brought on by dampness, damaged insulation, or other elements that jeopardize the grounding system’s integrity. It can result in circumstances that are unsafe and overcurrent.
4- Additional faults
- Inrush Current: Occasionally, a high beginning current drawn by the motor is confused with an overcurrent issue.
- Capacitor Faults: Overcurrent issues may also arise from difficulties with the capacitors in the VFD’s DC bus.
- Loose Connections: Unreliable drive performance and the possibility of overcurrent situations might result from loose wiring or connections.
- Excessive Moisture: Electrical issues such as short circuits can result from moisture intrusion.
- Internal VFD Failure: Overcurrent faults are another way that internal component failures might appear.
- Troubleshooting and Prevention: It is essential to do routine maintenance and inspections on the wiring, motor, and VFD.
1. Examine the area for any loose connections, high levels of dampness, and other environmental elements that can cause issues.
2. To assist in determining and optimizing motor characteristics, think about utilizing features like auto-tuning (if your VFD has them).
Overload vs Overcurrent in VFDs
Overcurrent and tripping on overcurrent are two different but connected failure states in VFD. The term “overload” describes a prolonged excessive current draw that usually exceeds the motor’s rated current by a specific percentage (for example, 150%) for a predetermined amount of time.
Conversely, overcurrent is a more general word that refers to any circumstance in which the current beyond a certain threshold, possibly including ground faults or short circuits, and frequently results in a much quicker reaction.
● Overload:
When a motor uses more current than it is rated to for a prolonged amount of time. Frequently brought on by an excessive motor load, mechanical problems such binding or increased friction, or irregularities in the process.
Often an electronic thermal overload feature, VFDs have built-in overload protection that keeps an eye on current and trips the drive if the overload condition continues. Overload faults are usually time-based, which means that if the overload continues, the drive will trip even though it can withstand brief current surges. A motor rated for 10 amps may cause an overload fault if the VFD detects 12 amps for longer than a minute.
● Overcurrent
A situation in which the current above a certain threshold, which might be significantly greater than the motor or VFD’s rated current. In addition to overload, short circuits, ground faults, and abrupt changes in load can also result in overcurrent.
To guard against damage from unexpected current surges, VFDs contain overcurrent protection, which frequently results in an immediate trip. The overcurrent protection on the VFD would probably trip right away if there was a short circuit in the motor wire.
Fault Analysis and Troubleshooting Methods
The drive is receiving excessive current from the power supply when a VFD tripping on overcurrent, which is frequently the result of a problem with the motor, load, or drive itself. Checking for any problems with the motor, load, and VFD, modifying settings, and confirming correct wiring and connections are all part of troubleshooting.
VFD Overcurrent Tripping Common Causes
Mechanical Problems
- Stuck or Bound Load: The motor may not be able to turn freely because the driven machine is stuck or hindered. Excessive Friction: The current draw may increase due to excessive friction caused by worn or broken load components.
- Motor Issues: Overcurrent may result from broken motor windings, short circuits, or ground issues.
VFD-Associated Problems:
- Inaccurate Parameters: Overcurrent tripping may result from improperly specified motor parameters, current limitations, or acceleration/deceleration timings.
- Faulty or Loose Connections: Overcurrent issues can also be caused by internal VFD component failures, damaged wiring, or loose power connections.
- Overheating: Overheating can lead to overcurrent by causing a number of components to fail.
Steps for Troubleshooting
● Visual Examination:
Look for any obvious indications of damage, such as burned parts, loose connections, or overheating, on the motor, driven machine, and VFD.
Look for any blockages or obstacles that could be preventing the motor from rotating.
● Verify the Connections:
Verify the tightness and security of all power and control wire connections to the motor and VFD. Check cables for exposed conductors or indications of damage.
● Confirm Motor and Load:
Use an insulation tester to check for insulation resistance, ground faults, and short circuits. Examine the driven machine for any mechanical problems, such as bending, friction, bearing wear or an excessive load, if the motor is operating as intended.
●Examine the VFD settings:
Verify that the VFD settings—such as motor characteristics, current limitations, and acceleration/deceleration times—are set appropriately in accordance with the application’s needs and the motor’s specifications.
●Incoming Voltage Check:
Confirm that the incoming voltage falls within the operational range of the VFD. If there are regular voltage changes, think about adding a voltage stabilizer.
●Take into Account Autotuning:
Make use of your VFD’s autotuning option to let the drive adjust its control algorithms and learn the motor’s characteristics.
●Monitor VFD Operation:
Determine the precise circumstances that caused the overcurrent trip by consulting the VFD’s fault history.
To assist in determining the reason, pay attention to the times of the travels, such as when the device is starting up or operating.
●Seek Professional Assistance:
Speak with a certified electrician or VFD specialist in R-Aletqan if you are unable to locate or fix the overcurrent issue.
Read about: What causes a VFD to trip
How to Fix VFD Overcurrent Faults
● Fixing an overcurrent in a VFD at startup:
- Check to see whether the machine is stuck or otherwise constrained, which would stop the motor from turning.
- Be careful not to short the motor.
- Make sure the motor’s legs are not shorted to the ground by using a megger.
- Make sure there is no damage or shorting to the VFD’s power module.
- Adjust the motor’s starting torque to the drive’s specifications.
● Taking care of an overcurrent that occurs when running:
Drive acceleration time should be increased if it is set too low. In case the deceleration time is set too low, raise it.
Quick Checklist for Troubleshooting VFD Overcurrent
- Verify the motor load.
- Look for physical damage.
- Inspect the power supply.
- Make sure the settings are correct.
- Check the control signals.
- Look for mechanical problems with the motor and load.
- Check for possible short circuits or ground faults.
Preventive Measures to Avoid Overcurrent Tripping
Avoid VFD tripping on overcurrent and avoid connecting too many high-power appliances onto one circuit, make sure that loads are distributed evenly among circuits, and perform routine maintenance and inspections on electrical systems to minimize overcurrent tripping.
For secure connections between several devices, use surge protectors and power strips.
A more thorough explanation of preventative strategies is provided below:
●Distribution and Load Balancing:
- Don’t overload: utilize many circuits: If at all feasible, utilize separate circuits for high-power appliances.
- When you need to utilize many devices in one place, use power strips and surge protectors to safely connect them to a single outlet.
●Frequent Inspection and Maintenance:
- Examine the wiring: Fix or swap out any malfunctioning parts.
- Cleanliness: To prevent improper operation, keep electrical panels and the surrounding regions clear of dust and dirt.
- Expert examinations: To find such problems before they become more serious, schedule routine electrical inspections by a certified electrician.
●Retrofit and Upgrade: Wiring
- To meet the demands of contemporary electricity, think about updating existing wiring, particularly in older residences.
- Components: Install safer, more recent switches, outlets, and circuit breakers in favor of outdated or insufficient ones.
●Safety Devices:
- To prevent electrical shock, install ground fault circuit interrupters (GFCIs) in damp locations like bathrooms and kitchens.
- To guard against voltage surges caused by lightning strikes or other occurrences, install surge protection devices (SPDs) at the main distribution panel or on designated circuits.
How to Reset a VFD After Overcurrent Trip
You can use one of the following techniques to reset a VFD tripping on overcurrent problem and restart the VFD:
●Resetting the fault manually is possible with many VFDs. To do this, hit a specific button on the keypad or display, such as “Reset” or “Stop/Reset.” Instructions for doing a manual reset should be found in the user manual for the particular VFD model you own.
● Resetting Digital Input: To fix issues with some VFDs, a switch or pushbutton that is connected to the terminal block can be utilized as a digital input.
- Automatic Reset: By enabling it in the programming options, certain VFDs include an automatic reset feature. After this feature is activated, the VFD will automatically try to reset the fault and start up again after a certain amount of time or after the fault state has passed.Applications where continuous functioning is essential and manual intervention is neither desirable nor practical may benefit from this capability.
- Remote Reset: Fault resets can be carried out remotely using a digital communication protocol like Profibus, Ethernet/IP, or Modbus when the VFD is connected to a PLC or another supervisory system, or when it is incorporated into a larger control system.
Need an Expert’s Touch?
You can trust R-aletqan to fix your VFD and any other motor controls you may have. In addition to offering a free assessment of the issue, we can fix and return your item more quickly than the OEM. Our 24-month service guarantee also covers your motor control.
For further information on our motor control repair services, contact us.
Conclusion
In industrial applications, dependable performance is ensured by addressing typical VFD issues through appropriate diagnosis, preventative measures, and prompt repairs. Effective maintenance of VFDs may be achieved by engineers through comprehension of common defects, application of strong diagnostic methods, and study of real-world case studies.
By prioritizing preventative maintenance and having a well-thought-out repair plan, VFD lifetime and downtime are increased, which boosts overall productivity and operational efficiency.
FAQs
1-Do VFDs have overcurrent protection?
Yes, overcurrent protection is a feature that is integrated into variable frequency drives (VFDs).
2-What is the HW overcurrent fault in Powerflex?
The drive’s output current is beyond the hardware’s current limit, which is normally between 200 and 300% of the drive’s rated current, according to a PowerFlex HW Overcurrent fault (usually fault code F12).
3-Why is my VFD showing overcurrent?
It ought to, which may be brought on by several things, such as mechanical, electrical, or improper VFD settings.
