Power Quality Problems That Quietly Wreck Drives, PLCs, and HMIs

by Bryan Hellman December 16, 2025

Industrial automation hardware is designed to be rugged—but it is not immune to poor electrical conditions. Voltage sags, spikes, harmonics, and transient noise can quietly cause drive faults, PLC resets, HMI lockups, and premature component failure. In many plants, these issues are misdiagnosed as “bad hardware” when the real culprit is the power feeding the system.

This guide explains how power quality issues manifest in real facilities, why they cause recurring downtime, and what practical fixes protect drives, PLCs, and HMIs already installed on your floor.

How Power Quality Problems Show Up on the Plant Floor

Power quality issues rarely announce themselves clearly. Instead, they appear as inconsistent, frustrating symptoms such as:

VFDs tripping during startup or load changes
PLCs randomly resetting or dropping I/O
HMIs freezing, rebooting, or losing communication
Motors running hot or experiencing shortened bearing life

Because these failures are intermittent, teams often replace the affected component—only to see the same issue return weeks later. That cycle is a strong indicator the electrical environment, not the device, is the underlying problem.

Why Replacing Hardware Alone Doesn’t Solve the Issue

When power quality problems go unaddressed, every replacement component is exposed to the same stress conditions as the last one. Over time, this leads to:

Repeated nuisance faults and unexpected downtime
Escalating maintenance and troubleshooting labor
Shortened lifespan of drives, power supplies, and control electronics
Higher long-term costs than addressing power stability once

Improving power quality is often one of the highest-ROI reliability upgrades a plant can make—especially for control systems and motor drives.

Confirming a Power Quality Issue Quickly

Spot checks with a handheld meter are rarely enough. Many power disturbances happen in milliseconds during motor starts, load transfers, or utility fluctuations. A more reliable approach includes:

Recording voltage and current over at least one full shift
Reviewing data during startup, shutdown, and load changes
Looking for sags, imbalance, or distortion that align with faults

Capturing real operating conditions helps confirm whether power events coincide with drive trips, PLC resets, or HMI failures.

Practical Fixes That Actually Reduce Automation Failures

1) Line Reactors and Input Filtering for Drives

Line reactors help stabilize the incoming power to a drive by reducing harmonics, limiting inrush current, and protecting internal components. They are especially effective when:

Multiple VFDs share the same transformer or feeder
Drives trip during facility-wide startups
Input rectifiers or DC buses fail prematurely

If your operation relies heavily on variable frequency drives, pairing them with proper input protection can dramatically reduce nuisance trips and long-term damage. You can explore drive platforms commonly used in these applications here:

ABB Variable Frequency Drives
Toshiba Industrial Drives

2) Regulated 24 VDC Power Supplies for PLCs and Controls

Many unexplained PLC resets trace back to marginal control power. Voltage dips that are harmless to motors can be disastrous for logic and communication hardware. High-quality, regulated 24 VDC power supplies are designed to ride through brief disturbances and isolate sensitive electronics.

For control cabinets using Siemens platforms, stable power supplies are a critical reliability component:

Siemens Power Supplies and Accessories

These supplies are engineered to support PLCs, HMIs, and I/O racks even when incoming power is less than ideal.

3) Surge Protection and Control-Level UPS

For deeper voltage events, generator transfers, or lightning-induced surges, adding protection at the control level can prevent silent damage. Small industrial UPS systems and surge protection devices help:

Keep PLCs and HMIs online during short disturbances
Prevent corrupted programs and communication faults
Protect expensive drive and control electronics from spikes

These solutions are especially important for systems where a reboot alone can cause lost production or quality issues.

Power Quality and Motion Systems

Servo systems and motion control are particularly sensitive to unstable power. Inconsistent voltage can lead to following errors, amplifier faults, or loss of position. If your plant uses legacy or high-performance servo platforms, power conditioning becomes even more critical.

Examples of motion hardware commonly affected by power quality issues include:

Mitsubishi MR-J2S Servo Drives

Making the Fixes Stick

To avoid repeat problems, power quality improvements should be documented and standardized:

Apply fixes first to circuits with the highest downtime impact
Capture before-and-after data to verify improvement
Update electrical and control documentation
Pair improvements with a known-good spare parts strategy

This turns a one-off fix into a long-term reliability upgrade.

How Industrial Automation Co. Can Help

Industrial Automation Co. supports maintenance and engineering teams by helping identify compatible drives, PLC components, power supplies, and motion hardware that fit real-world operating conditions. When power issues expose weak points in a system, having the right replacement—and the right supporting components—makes recovery faster and more reliable.

Contact Industrial Automation Co. for help sourcing and validating automation components

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