5 Tips for Preventing VFD Cooling Failures and Overheating

VFDs work hard. But when they overheat, everything else slows down — or shuts down completely. Cooling problems might start small, but they don’t stay that way for long. A fan goes out. Filters clog up. Heat sinks can’t keep up. Suddenly, the drive is tripping or failing, and production takes the hit.

The good news? Most VFD cooling failures are avoidable. Here are 5 early warning signs, to help you keep drives within safe temperature limits (and improve their reliability).

1. Start with airflow: Is anything blocked?

Cooling starts with clean intake. If filters are clogged or vents are blocked, heat builds fast. Dust, oil mist, and debris restrict airflow, forcing fans to work harder and reducing the drive’s ability to shed heat. Here’s what to look for:

• Visible buildup on intake screens or cabinet filters.
• Filters that feel dense or resist airflow when held up to a fan.
• Fan noise that sounds strained or irregular.
• Dust deposits or discoloration near heat sinks.

2. Inspect fans: Wear, failure, or wrong direction.

Fans pull air through the system to cool internal components. But when they slow down, reverse direction, or fail completely, heat has nowhere to go. Malfunctioning fans are one of the most common causes of VFD overheating. Here’s how they give themselves away:

• Excess noise or vibration from the fan housing.
• Fan blades turning the wrong way due to incorrect wiring.
• Intermittent shutdowns triggered by rising internal temps.

3. Take a closer look at ambient temperature.

Even if the VFD itself is functioning perfectly, a hot room can work against it. Drives are often tucked into tight panels or crowded enclosures, and without enough ventilation, the entire space becomes a heat trap. Symptoms tied to ambient heat include:

• Drive temperatures approaching or exceeding manufacturer specs.
• Multiple VFDs in one panel overheating in sequence.
• Higher failure rates during summer or near high-load machinery.

4. Check heat sinks for dust buildup and loose contact.

Heat sinks help move thermal energy away from sensitive components. But if they’re caked with dust — or not seated properly — their ability to conduct heat drops off fast. It doesn’t take much buildup to make a difference. Here’s what to watch for:

• Discoloration or warping on heat sink fins.
• Uneven surface contact between the heat sink and the drive body.
• A sharp rise in temperature under consistent loads.

5. Don’t ignore thermal alarms (they’re warning you).

Modern VFDs come equipped with onboard diagnostics that monitor internal temps. These alerts aren’t just noise — they’re a direct signal that something in the cooling system is under stress. If alarms keep appearing, take them seriously. Some common triggers include:

• Frequent thermal derating or shutdown events.
• Alarms that correlate with high ambient temps or peak production.
• Error logs showing temperature spikes with no obvious cause.

Professional repair, for when troubleshooting isn’t enough

If cooling issues continue even after cleaning filters, replacing fans, and adjusting airflow, deeper component problems could be at fault. Damaged sensors, degraded capacitors, or failing power components may be generating more heat than the system can handle. That’s when expert diagnostics and repair can save time — and the drive.

Now through the end of the month, GES is offering 10% OFF single repairs or 15% OFF 3+ repairs on ABB products, including VFDs. If you’ve got a VFD battling heat-related issues, we’ll get it back up and running reliably!