You can feel productivity leeching away as soon as it happens, sometimes even moments before your hear an alarm — the line goes down. Under pressure to minimize downtime, you trace the interruption to a variable frequency drive (VFD). These basic tips can help you walk through troubleshooting a variable frequency drive before you get on the phone with the manufacturer.
Refer to the display for diagnostics
Many VFD displays will have some troubleshooting functionality baked in. If your VFD offers this function, run the diagnostics for quick insight on any blown fuses, trips, overheating or unbalanced voltages. Your VFD display can help you pinpoint issues with the current during sudden load changes or speed ramps. As a general rule, line voltage should be balanced within five percent.
Assess the environment
Don’t overlook external problems near the equipment. High humidity, extreme temperatures or temperature fluctuation, and even vibration can severely impact functionality. Is the VFD dusty, dirty, or corroded? If you wouldn’t trust sensitive electrical devices your like TV or computer in this environment, it may be affecting performance in the short-term and VFD efficiency in the long-term.
Look for loose connections
Loose connections are one of the most common causes of downtime with VFDs. If a loose wire isn’t obvious at a glance, be sure to measure voltages for drops across the connection when powered up, or resistance when powered down. You’ll need an ammeter and oscilloscope to make appropriate measurements, so keep these basic tools on hand. As always, prioritize industrial safety while working with powered equipment.
Call the Manufacturer — Or Your Distributor
If these three steps fail to reveal the root cause or unearth an even bigger problem, the next step is to call the manufacturer — or your distributor. VFD manufacturers know their products inside and out and want you to be satisfied with their product, but may be fielding thousands of troubleshooting calls a day.
If you’re partnered with a knowledgeable industrial electrical supplier like ACD, you can reach an engineer directly and receive personalized support from someone who knows you and your business. Contact us to find out how we can deliver industry-leading electrical products with in-depth, responsive support: