RENOVATION TECHNIQUE OF SINGLE LAYER WINDING INSULATION OF ASYNCHRONOUS MACHINES

摘要

The invention refers to the area of electrical engineering and can be applied in AC electrical machines. The aim is to eliminate the insulation damage of asynchronous machine winding in respect to its body and to prolong service time. The offered renovation technique of single layer winding insulation of asynchronous motors is characterized in that each winding of machine stator and rotor separately is connected to a low voltage DC power supply (storage battery), and an attractive force is determined between the winding being subjected to testing and a ferromagnetic parallelepiped having height and width of the groove where winding of stator or rotor is located. Said parallelepiped, used as a testing specimen, is fixed to a spring balance perpendicularly to the groove and definitely spaced from the winding coil end. The winding with lower attractive force is impregnated with liquid insulating material, e.g. schellac. In steady-state conditions the windings are heated up to 70 0C expending the electric current from storage battery and cooled. When the attractive force in all grooves becomes equal, the real value of the machine electrical insulation is checked with respect to its body.