VFD and PLC Systems Tripping, Resetting, and Failing Even When Wired Correctly
Electricians and maintenance teams are often called in after failures start. The VFD keeps tripping, the PLC resets randomly, or automation equipment faults without a clear cause. Wiring and grounding usually check out, and replacing the drive or PLC may provide only temporary relief. In many cases, the real problem is ongoing power disturbances that slowly damage electronic components. Voltage transients, electrical noise, and surge energy entering through power and control circuits degrade equipment until downtime becomes unavoidable.
VFDs and PLCs are closely linked and are frequently affected by the same power quality issues. High speed switching inside a VFD generates internal transients that can travel through shared distribution paths and impact other drives, PLC power supplies, and control electronics. External disturbances such as utility switching, lightning activity, and large motor starts introduce additional stress. The result is nuisance trips, control cabinet electrical noise, PLC power supply failures, and unpredictable system behavior even in properly installed systems.
TPD surge protection addresses these problems at the source. Protecting the incoming power to the VFD is the first step. For Delta systems or Wye systems where the neutral is dropped (no neutral), installing a no neutral surge protector at each drive, or at the drive cabinet or motor control center feeding multiple drives, stops destructive surge energy before it reaches sensitive electronics. For 480 volt no neutral VFDs, the TPX-480NN-F-100 provides effective surge protection. For 240 volt systems, the TPX-240NN-F-100 offers the same level of protection in a compact, industrial rated design.
Control circuits also require protection. Most industrial systems use either 24V or 120V control power, and these circuits are highly susceptible to transients. Long control wire runs can introduce surge energy directly into PLCs, I/O modules, and communication cards. Adding a series-wired surge protector on the control circuit creates a critical second layer of defense. The TPD-DM24-15A is well suited for 24V control circuits, while the TK-LT120-15A-DIN2 protects 120V PLC and control power supplies from damaging surges that lead to resets and failures.
At TPD, surge protection is applied where failures actually occur, not just at the service entrance. Equipment level protection at the VFD, the control cabinet, and the distribution points feeding automation systems reduces downtime, limits service calls, and extends equipment life. When surges and transients are controlled at their source, VFDs remain stable, PLCs stay online, and industrial processes operate reliably.
If you have a VFD system that needs to be protected, please reach out to us at TPD at info@tpdsurge.com or 888-281-7856. We are happy to help and will find you just what you need!
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