Troubleshooting ACS355 Drives: Persistent Overcurrent Faults Explained

Question:

I operate two ACS355 drives (240V, 1HP), each linked to a Marathon Black Max 1HP motor. Shortly after starting the drives (within 5 seconds), both systems trigger an overcurrent fault. Initially, I configured the drives for vector speed mode, but when I encountered this issue, I switched to scalar mode, and the problem persisted. To troubleshoot, I disconnected the motor leads from the drives and attempted to start them in scalar mode; surprisingly, I still received an overcurrent fault. Remarkably, even with the motors disconnected, the current feedback value on the drive remains at zero, yet both drives still fault for overcurrent. This occurs regardless of whether they're connected to different motors or not connected at all. I'm seeking guidance on this issue, which seems to be a setup error, but I can't identify what could be causing this anomaly. I've never experienced anything like this before, especially not from two brand-new drives. Any insights or solutions would be greatly appreciated. - Keith

Top Replies

What is the condition of the environment? It seems like there may be condensation occurring in the motor, although I am unfamiliar with the specific brand of this motor. If you notice the motors producing this sound during acceleration, consider checking parameter 3104. I recommend being present on-site to closely monitor their performance if you choose to proceed with testing.

Is it possible that the Variable Frequency Drive (VFD) has sustained damage? When operating under no load, it resembles a shorted Insulated Gate Bipolar Transistor (IGBT). Might there be a requirement for line reactors in this scenario? I recall a previous experience with a compact Powerflex drive that triggered a hardware overcurrent fault while at rest. The introduction of a line reactor resolved the issue. However, I must clarify that I initially misreported the problem—I was encountering overvoltage faults rather than overcurrent.

We are currently in the early phases of conducting machine tests at a leading Original Equipment Manufacturer (OEM). The industrial environment where this is taking place is exceptionally clean, free from dust or aerosol particles, located in the northern United States. Interestingly, the humidity levels are notably low for this season. In our setup, we have two identical drives positioned closely together within an enclosure, and crucially, they are NOT connected to any motors; their output terminals are also disconnected. This testing approach aligns with the ABB manual troubleshooting procedures. Both drives are brand new, so while it's feasible that both could be defective straight from the factory, I typically don't experience such unfortunate circumstances. This leads me to suspect a configuration issue, although I struggle to identify any specific parameter that could be causing this anomaly. Best regards, Keith

Ensure you save your progress, then restore the settings to their default configurations. Next, switch to scalar mode and conduct another test without any connected load for optimal results.

Keith, it's worth noting that the ACS355 series seems to be the less favorable option compared to the premium ACS800 ABB variable frequency drives (VFDs). I’ve utilized the ACS355 series on occasion, primarily when faced with stringent budget constraints. One significant issue I've encountered is its tendency to trigger 'Overcurrent' faults, particularly during sudden load fluctuations, even when operating within specified limits. Adjusting the acceleration and deceleration settings helped reduce some of these nuisance trips; however, there were instances where I had to upsize the drive to meet performance needs. I'm uncertain whether operating the drives without an electrical load is an appropriate troubleshooting method, regardless of ABB's recommendations, as this practice could potentially harm the inverters. I recommend reviewing parameter 2606 (SWITCHING FREQ) and ensuring it is set to the default value of 4kHz. Additionally, set parameter 2607 (SWITCHFREQ CTRL) to 'ON' instead of the default 'ON LOAD.' This adjustment should optimize performance when using a 4 kHz carrier frequency. It appears that the onboard processor may struggle with switching the modulating signal promptly enough to accommodate the mechanical load's fluctuations. By considering these adjustments and conducting thorough troubleshooting, you can enhance the reliability and efficiency of your ACS355 drives.

Hey Keith, it sounds like you’re dealing with a perplexing situation! Since the drives still trigger an overcurrent fault even with the motors disconnected, it could suggest a potential issue with the drive settings or connections themselves, rather than an actual motor problem. Have you checked the wiring and terminal connections for any shorts or miswiring? Sometimes, interference from other devices or incorrect parameters in the drive configuration can also lead to unexpected faults. Additionally, if these drives are brand new, it might be worth reaching out to the manufacturer’s tech support for further diagnostics, just to rule out any factory defects or guidance on setup adjustments!

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Frequently Asked Questions (FAQ)

FAQ: To troubleshoot persistent overcurrent faults in an ACS355 drive, you can follow these steps:

Answer: 1. Verify all drive parameters and settings to ensure they match the motor specifications and application requirements. 2. Inspect all wiring and connections for shorts or incorrect wiring. 3. Reset the drive to factory settings and re

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