Is the insulation material of the motor determined by the magnitude of the current or the voltage?

Is the insulation material of the motor determined by the magnitude of the current or the voltage?

Insulation material is an important key material for motor products. Motors with different voltage levels have great differences in the insulation structure of their windings and their key components. For example, the insulation structure of high-voltage motor and low-voltage motor windings is very different. .

Insulating materials, also known as dielectrics, are materials with very high resistivity and very poor conductivity. They are also used in motor products because of their poor conductivity. In motor products, through insulating materials, on the one hand, the conductive wires are connected with other components. Separation, on the other hand, is to separate different points of the conductive line, such as inter-turn insulation and inter-phase insulation. Different insulating materials can also have various properties such as support, fixation, arc extinguishing, mildew resistance, radiation protection and corrosion resistance.

The burning of the motor windings is a concrete manifestation of the deterioration or disappearance of the insulation performance. Then, is the insulation performance of the motor degraded due to the large winding current or the high voltage?

When the motor winding current is too large, the higher current density will cause the winding resistance to increase and cause serious heat generation. The heat generated by the motor will be dissipated through the insulation. When the heat reaches a certain level, the structure of the insulating material will undergo qualitative changes, such as the motor The performance requirements of different insulation grades such as B, F, and H involved in the table correspond to the maximum working temperature that the insulating material can withstand.

For the motor winding, the insulation requirements between turns and turns, between different phases of a multi-phase motor, and between the conductor and the ground are involved. When the rated voltage of the motor is higher, the voltage of the winding insulation is also higher, which can be simply Think of this as different capacitors. If the voltage between the capacitors is too high, it will lead to the problem of capacitor breakdown, that is, the insulation failure of the motor winding to ground, between turns and between phases.

From the above content, we can understand that although the current of the high-voltage motor is small, the insulation voltage of the windings is high, so a special insulation structure must be used to ensure that the electrical performance of the motor meets the requirements; while the low-voltage motor, because the insulation voltage is relatively high Therefore, the selection of insulating materials is relatively simple, but current density, ventilation and heat dissipation are the key factors to ensure the electrical performance of the motor. The current and voltage of the motor have different influences on the insulating material and must be taken into account at the same time.