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3 Ways Environment Can Affect Your AC Motor

There are many reasons behind an AC motor failure or a drop in performance. From defective rotors, stators and bearings to incidents like electrical overloads and excessive vibration – they all can contribute to a breakdown in your AC motor.

While the list of causes is exhaustive, you can take your time to learn about each one of them slowly. As you start to understand the various underlying causes, you will understand how to take care of your equipment better and the measures to take when a malfunction happens.

At the very least before you call in your trusted engineer for an electric motor overhauling, you would have already known the issue beforehand. In this way, it will make it easier for both sides to salvage the faulty AC motor.

Below, we will be listing three environmental factors which will deteriorate your AC motor’s performance.

Poor ventilation

Among many factors, one of the most overlooked environmental factors of them all is poor ventilation. Otherwise, also known as dirty or polluted air.

Unfortunately, such a situation is unavoidable and requires frequent monitoring and assistance. If not, one might have to source for other alternatives like a Totally Enclosed Fan-Cooled (TEFC) motor to ensure excellent ventilation for your electric motor.

But the air might not always be as bad as it seems and it could just be due to the weather at that moment. Instead of making an unnecessary or unrewarding investment, it’s best that your engineer takes a close look at both the environment and AC motor.

Drastic changes in temperature

Whether the temperature is too hold or cold – they’re both equally bad for your AC motor.

After rigorous testing and checks by manufacturers, AC motors already come with optimal temperature ranges for the best operational performance. So, you have to do your part by adhering the stated specifications closely to ensure your AC motor is always at tip-top condition.

Typically, the ideal temperature for industrial AC motors is approximately from -40° to -20° Celsius (C). However, in a case where the air temperature will drop below -20° C – you’ll have to ensure grease-lubricated bearings are properly coated with grease. Meanwhile, oil-lubricated bearings will require a thermostat-regulated oil-sump heater to heat up the oil.

On the other hand, when the air temperature goes over +40° C – there is a need to come up with ventilation/ambient cooling measures. Or else, you may have to consider electric motor rewinds as your go-to option and rewind your AC motor to a higher class of insulation.


Just like how your AC motor already has an optimal temperature range, industrial motors typically have a fixed altitude they should stick to.

Usually, it’s an altitude of 1000 metres (3281 feet), where ambient air has a lower cooling capacity. Here’s a general rule for altitude – every added 100-metres of height above the altitude of 1000 metres, a motor will have to be de-rated by 1%. So, this would mean that at an altitude of 3000 metres, it would have to be de-rated by 20%.

The best option in a case scenario such as this would be to simply pick a motor the next size up.

At the end of the day, you have to know that your AC motor will be affected by several factors which will cause its efficiency and performance to decline. However, by knowing the different causes as stated above you will know what kind of issue your equipment is dealing with.

Not only is it a good start to understanding your AC motor better – but you will also be able to communicate the problem to your engineer much easily.