What are the types of motor insulation and what are the important effects?

Update:22 Feb 2020

  The motor insulation includes the inter-strand, […]


The motor insulation includes the inter-strand, inter-turn, row, inter-layer and ground insulation of the coils, and various end supports or fixings of various insulation members and connection and lead insulation.

The main insulation of a coil refers to the insulation between the coil and the body and other windings. It is also commonly called insulation to ground.

Interturn insulation refers to the insulation between turns of the same coil.

Inter-strand insulation refers to the insulation between strands within the same turn, and is generally the insulation of the winding wire itself.

The insulation of the motor is an important factor that determines the service life of the motor, so the insulation materials must be properly selected and placed. Asynchronous motor stator winding insulation is divided into slot insulation and phase insulation (interlayer insulation is not needed here).

1) Slot insulation is used in the slot, which is the insulation between the winding and the iron core.

2) Phase insulation, also called end insulation, is used for insulation between two windings at the end of the winding.

3) Interlayer insulation is used for insulation between the upper and lower layers of the double-layer winding. The insulation material is the main insulation material selected according to the insulation level and voltage level of the motor, and is equipped with appropriate reinforcement materials to protect the main insulation material from mechanical damage. Commonly used reinforcement materials are green shell paper, and the main insulation materials are polyester film and varnished cloth. When selecting insulation materials, the main insulation materials and lead wires, bushings, binding wires, dipping varnishes, etc. should be of the same insulation level and used together with each other.