The insulation class of electric motors is an important point to consider when selecting a motor for a specific application, such as fans, compressors, drive motors, in transportation, in light and heavy industry, as it indicates the capacity of the motor to resist electrical and thermal stresses, and therefore allows to predict its duration over time.
Electric motors can be classified into three main insulation classes, from the lowest to the highest: class A, class B and class F, as required by the CEI EN 60335-1 standard.
Why protect electric motors from overheating?
Electric motors generate heat during their operation, so a higher insulation class means that the motor can withstand higher temperatures. Choosing an electric motor with a higher insulation class, therefore, allows greater protection against damage caused by overheating and therefore greater resistance and durability of the product.
What differentiates the insulation classes for electric motors?
The CEI EN 60335-1 standard establishes the following temperature values for the three main insulation classes of electric motors:
Class A
Class A is the lowest class and is commonly used in low voltage and current applications.
Class A motors are designed to withstand maximum operating temperatures of 105°C/221°F. This makes them suitable for applications where the ambient temperature is relatively low and the motor is not subjected to heavy loads. For example, this insulation class is commonly used in fans, compressors and other similar applications.
Class B
Class B falls between the two, and is used in high voltage and current applications.
Class B motors are designed to withstand maximum operating temperatures of 130°C/266°F. This makes them suitable for applications where the ambient temperature is relatively high and the motor is subjected to moderate loads. For example, this insulation class is commonly used in drive motors, transportation and industry.
Class F
Class F is the highest class and is commonly used in high power applications.
Class F motors are designed to withstand maximum operating temperatures of 155°C/311°F. This makes them suitable for applications where the ambient temperature is high and the motor is subjected to heavy loads. For example, this insulation class is commonly used in heavy industry and specialized transportation.
In general, class F motors are suitable for applications where high power is required and where safety against overheating and overvoltage may become critical.
How to choose the insulation class?
From a first reading, one could think that choosing a higher insulation class for an electric motor will guarantee greater safety and a longer life for the motor. This is true, but we must also take into account the costs and weight of the engine, which increase in proportion to the increase in the class. Fandis fans range covers all three classes and, in the next articles, we will provide further insights on this topic, to guide users towards a more informed and targeted choice of the type of application. To stay updated on the release of the next online articles, follow us on LinkedIn!
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