If you have medium voltage drives, then you know how challenging it can be to monitor, take readings, troubleshoot, and get them back online when a failure occurs. In this article, EMA’s Trey Mayfield discusses the shortcomings of widely accepted traditional methods and how you can save yourself a lot of headaches, time, and money with a new method using a remote monitoring solution.
Why Existing Drive Monitoring Methods Aren’t Good Enough
Medium voltage variable frequency drives are complex pieces of equipment and subsequently are tough to monitor as well. Instruments exist that can monitor and trend the power coming into a drive. Other instruments exist that can monitor aspects of the motor the drive is running, but there is a lack of real-time data from the medium voltage variable frequency drive itself. Monitoring the health of the drive itself is currently an after-thought and maintenance personnel are tasked with reactive troubleshooting and monitoring; readings on the drive are often taken only after an event occurs that stops production. When data is needed from the medium voltage VFD, the safety protocols and setup takes time. The onsite technician first has to remove power from the drive, lock and tag it out, open all the doors to the VFD, place his specialty tools on the area(s) they need to test, then close all the doors again, take their locks off, and re-power up the drive. This traditional, hands-on method requires time, that some facilities strictly don’t have. Not to mention the various forms that your organization might require to be filled out before any work is to be done at all. Thankfully, there is a revolutionary new way to take all of these readings without doing any of this, from the comfort of your desk.
As a service engineer myself, I can’t tell you how many times a customer has called with a complaint on a VFD, I traveled all the way there (sometimes a day of travel or more), and by the time I get there, the problem has gone away. Even if production will give me the drive to troubleshoot (which they often won’t if its running), duplicating an intermittent problem is often extremely hard. The problem causing the intermittent issue usually finds a way to return when I’m already on the airplane back home. Current drive monitoring methods are extremely frustrating, especially when the issue is intermittent. Onsite personnel take readings strictly hoping that the issue will rear its ugly head while they are there, which it often doesn’t. Chasing intermittent faults is frustrating and time consuming, not to mention expensive. A typical medium voltage service call costs at least $7,000. And even the most highly skilled variable frequency drive engineer in the world is only as good at the data given to him.
Drives Diagnostics Do Not Do Root Cause Analysis (RCA)
Modern medium voltage variable frequency drives generally have good fault diagnostics. IF all the fault sensing circuitry is working properly, a medium voltage VFD will give the user a fault code that assists them in troubleshooting. The problem is the VFD can’t tell you what is causing the fault. Overcurrent is an example of this. Overcurrent is a very typical fault given by most VFDs. The drive is telling you that it “thinks” the motor is asking for upwards of 200-250% of the VFD’s rated current, and as a result, the VFD shuts itself down to prevent damage to its components. The culprit causing this could be multiple things: Outside factors such as the motor or the load itself, or internal factors such as a shorted transistor or compromised driver circuitry. Either way, VFD fault circuitry is limited in what it can tell you about the fault or why it occurred. There is a better way!
There is a Better Way
What if I told you there was a way to not only measure but trend the outside factors (input voltage, input current, power quality, output voltage, output current) and internal factors (DC bus, power supplies, and environment) of the VFD? And, what if we could determine the cause of that overcurrent from any computer screen in the world? DriveScan offers you these abilities. By monitoring and trending all of these factors, 24/7, 365, maintenance personnel and reliability engineers within your organization have access to much more data about the drive’s health than ever before. Information in any situation is powerful, and could save you hundreds of thousands in downtime and onsite service call fees. Not only does your organization have access to this data, DriveScan’s cloud-based monitoring system allows the experts at EMA and Powerside to partner with you to resolve your problems. You’re not alone when your drive goes down.
Predictive AI Helps you Prevent Future Drive Failures
Tradition monitoring methods not only are inadequate for troubleshooting present issues, they certainly don’t help you predict future issues. DriveScan is gathering data continuously not only from your medium voltage VFD, but from every other similar medium voltage VFD that has a DriveScan installed on it. The artificial intelligence within the cloud based monitoring system becomes intelligent about predicting future failure events, and the longer it trends, the more intelligent it gets! With baseline data established, DriveScan will alert you to potential problems that could arise in the future based on real, trended data, not educated guesses. It is continuously monitoring your medium voltage VFD’s health, all day, every day and looking for trends headed away from the baseline. Never before has this type of data been available. This information is invaluable for maintenance planners planning their next outages or reliability engineers planning their next upgrades. Let DriveScan help you stop minor issues BEFORE they become major ones.