A Variable Frequency Drive (VFD) controls the speed and frequency of applications to improve their efficiency, lifespan, and performance. When it comes to ensuring your VFD's safety, system performance, and warranty protection, proper VFD wiring is a must.
Is your VFD correctly wired? Read on to learn more about the importance of proper VFD wiring, the top causes of VFD failure, early warning signs to look out for, and how Lemberg can help.
A VFD is a speed regulation device that can be added to a motor drive system to improve machine efficiency, longevity, and process control. VFDs are used in various applications, including HVAC systems, conveyors, industrial and manufacturing lines, mining equipment, healthcare systems, BAS systems, and much more. They are used to save energy, improve application performance, and preserve the application's lifespan.
Keeping your VFDs in a clean, cool, and dry environment is essential to ensuring their longevity. However, even with these precautions in place, improper VFD wiring can still lead to major failures.
Maintaining proper wiring of your VFD is critical for ensuring safety, system performance, and warranty protection. Facilities managers can assess appropriate VFD wiring from the electrical control panel. It is important for your wiring to be rated to match your specific VFD. It is also important for your VFD to have a dedicated raceway/conduit placed far enough away from other wiring to avoid electrical interference.
Incorrect or improper wiring can degrade the conductor's insulation and cause phase-to-phase or ground faults, leading to VFD failure.
Improper VFD wiring can lead to Electrical arcing and failures, which pose serious safety risks to employees. Exposure can result in electrical burns, thermal contact injuries, bruises, fractures, hearing or vision damage, and even death. These incidents can also spark fires or explosions—particularly dangerous in critical environments like hospitals or industrial facilities. Beyond safety concerns, improper VFD wiring can void manufacturer warranties, leading to costly replacements and extended downtime.Improper VFD wiring can lead to
Ensuring correct VFD wiring is not just a best practice—it’s a smart investment in reliability, safety, and operational continuity.
Learn more about the dangers of arc flashes in this blog post.
Common factors contributing to VFD failure include loose connections, voltage or current surges, temperature fluctuations, dirt and dust, chemical exposure, moisture, corrosion, incompatible motors, and cable abrasion.
Among these, incorrect wiring techniques are the leading cause, followed by running multiple motor wires through a single conduit and using excessively long cables without appropriate supporting components.
The most common—and most preventable—cause of VFD failure is incorrect or improperly rated wiring. If the cable doesn't match the manufacturer's specifications for voltage, shielding, and insulation, the VFD becomes vulnerable to:
The Lemberg team noticed a pattern across several of our manufacturing customers: their VFDs were failing well ahead of schedule. Further inspection revealed the failures were caused by incorrect wiring, leading to ungrounded power that degraded the wiring insulation.
Ensuring proper wiring is often a crucial step skipped during initial installation due to factors like time or budget. Because there is no immediate consequence, the issue can emerge a few years into the lifespan of your VFD (when you least expect it).
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Another critical mistake that can lead to a VFD wiring failure is routing more than one motor wire through the same conduit. While this may seem like a way to simplify or reduce wiring runs, it causes crosstalk—an electrical phenomenon where signals from one wire interfere with those in another.
This electrical interference leads to the following:
This miswiring can create serious operational inconsistencies in high-performance environments, particularly those running conveyor systems or automated machinery. Therefore, separating the wires is extremely important for avoiding VFD failure.
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When wiring between the control panel and the motor exceeds 15 feet, standard building wire cannot effectively smooth out voltage waveforms, which leads to stress on the drive and motor system. The result? A VFD that fails far earlier than expected, sometimes without any obvious warning signs.
To prevent this issue, a qualified electrical contractor can evaluate cable lengths, the application's unique demands and VFD manufacturer's specifications. They'll recommend using specific components, such as line reactors, dV/dt filters, or shielded VFD cable.
Without these protections, the extended cable distance amplifies the chance of:
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Your maintenance teams and operators will want to watch for these common signs that may indicate VFD failure:
Regular monitoring for warning signs of potential VFD failure is the best practice for maximizing system longevity and performance while minimizing operational disruptions and costs. It's essential to have a trusted electrical expert on call to install, monitor, and manage your VFD system to maintain safety measures, system performance, and warranty protections.
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If you're unsure about the condition of your VFD wiring, or if you've experienced warning signs or premature failures, Lemberg Electric is here to help. As a trusted electrical contractor serving industrial, manufacturing, and healthcare facilities across the Milwaukee area, we've been helping businesses operate safely and efficiently for nearly a century.
Our award-winning team brings unmatched expertise in critical infrastructure and industrial electrical systems. Whether you're installing new equipment, troubleshooting ongoing issues, or seeking peace of mind with a proactive inspection, we can:
Don't leave something as critical as your VFD wiring to chance. Contact Us Today for expert VFD wiring help.