That day the machine tripped unexpectedly, and the supervisor's face was colder than ice
To be honest, I remember that trip; it was an absolutely dreadful Friday afternoon. You've probably experienced it too, right? Just a few minutes before knocking off, a sudden "bang" came from the production line, followed by a piercing alarm. That machine, our production line's star performer, unexpectedly shut down just like that. The supervisor rushed over, his face ashen, asking, "What's the situation? Equipment team, give me an explanation!" At that moment, a few of us were dumbfounded. We opened the electrical cabinet; no smoke was seen, no burning smell was detected, yet it had stopped. Only later did we discover that a connection point in the electrical panel had overheated and burned out, causing a protective trip. The shutdown alone resulted in hundreds of thousands in losses, and since it happened right before closing, we spent the entire weekend chasing reports—it was truly miserable.
What's the problem? Heat, the invisible killer.
To put it plainly, a large majority (about 80%) of electrical equipment failures are caused by "heat." You might find it strange; wires and connection points appear perfectly fine, so how could there be an issue? Frankly, the human eye simply cannot detect temperature anomalies. But these invisible hot spots are actually like ticking time bombs. When electrical equipment operates under overheated conditions for extended periods, insulation materials will age, and conductors will oxidize. This increases resistance, generating more heat, creating a vicious cycle. Eventually, there's a "bang," a trip, or a burnout. At best, production halts; at worst, it causes a fire, which is no laughing matter. So the key is that we need a pair of eyes that can "see" temperature to detect these potential crises early. This is where thermal imagers come into play.
How to actually do it? Use thermal imagers to uncover hidden problems
Simply put, a thermal imager is a tool that converts the surface temperature distribution of an object into a visible light image. It allows you to instantly see where something is "running a fever." For preventive maintenance in our factory, we regularly use thermal imagers to scan critical electrical equipment such as transformers, switchgear, motors, and electrical panel connections.
Let me give you an example: we had a machine motor where, after a thermal scan, we found that one of its phase connections was approximately 25°C higher than the other two phases. Normally, for such connections, a temperature difference should ideally be kept within 5°C for safety. At that time, the temperature of that specific connection had already reached 85°C, while adjacent normal connections were only 60°C. Once this temperature difference appeared, we immediately knew there was a problem there. Upon disassembly and inspection, it was indeed found that a fastening screw was loose, causing poor contact, increased resistance, and thus overheating. If not discovered early, that motor would likely have burned out within another month.
So the key is that once you scan the equipment and observe an abnormal temperature difference, you should immediately schedule remediation. Here's a rule of thumb you can refer to:
- Temperature difference ≤ 10°C: Minor anomaly, continue monitoring and prioritize for the next inspection.
- 10°C < Temperature difference ≤ 20°C: Moderate anomaly, requires scheduled shutdown for inspection or repair.
- Temperature difference > 20°C: Severe anomaly, immediate shutdown for inspection, likely already damaged.
Of course, these numbers are just a reference and should be judged in conjunction with the type of equipment and ambient temperature.
The most common pitfalls: Buying it and not using it, or using it incorrectly
Many people might think, "Thermal imagers are expensive, right?" In fact, entry-level thermal imagers are now quite affordable. But the biggest pitfall isn't the cost, but rather buying one only for it to "collect dust" or "be used incorrectly." I've encountered colleagues who grabbed the thermal imager and just randomly scanned, claiming a problem wherever something looked bright. It turned out to be either reflected light or an overheated background, completely missing the actual issue.
Another common pitfall is only looking at absolute temperature, not temperature difference. Some equipment naturally operates at high temperatures. If you only see it measuring 80°C and think, "Ah, it's hot!" but an identical adjacent connection point is also at 80°C, then it might be a normal operating condition. Therefore, the key is to compare the "relative temperature difference" between different points within the same equipment; this is critical for identifying anomalies. Also, when scanning, ensure the equipment is operating under normal load; otherwise, with no current, the temperature will naturally appear normal, and nothing will be detected.
One thing you can do today
Integrate thermal imagers into your preventive maintenance plan, starting today.