Insulation heat resistance class is one of the key characteristics of the winding. It determines at what temperature the engine can operate for a long time and reliably. Let's look at this concept.
What does this mean
The insulating materials of the winding can withstand a certain temperature limit. Heat resistance class is exactly the maximum temperature at which the insulation serves the design period (usually about 20 years).
| Class | Limit temperature |
|---|---|
| A | 105 °C |
| E | 120 °C |
| B | 130 °C |
| F | 155 °C |
| H | 180 °C |
The rule of doubling the service life
There is an important rule: exceeding the maximum temperature for every 8-10 °C reduces the service life of the insulation by approximately 2 times. This explains why overheating is so destructive: even a small but constant increase in temperature “eats up” the life of the winding many times faster.
Why is this important when rewinding
When rewinding the insulation class of the materials must be no lower than the original one. It is often advantageous to use a higher class (for example, F instead of B) - this increases the heating margin without changing the dimensions. This is especially true for hot shops and difficult conditions in Tashkent. The correct choice of materials is part of quality repair.
Are you planning to rewind with increased heat resistance in Tashkent? Elektromotors engineers will select materials to suit the conditions - contact us.