Many of you may have heard about rewinding a motor. It is necessary to rewind a motor when its winding get defective. It happen in many ways. But the common fault is burning of winding due to insulation failure or overload. Here I am trying to explain the rewinding process of a slip-ring induction motor. This is a 435kW induction motor rotor. This is the rotor that we are going to rewind. All the coils are removed from the slots and it is cleaned. After that two coats of red varnish is applied. This is to improve the insulation resistance value and to protect core from corrosion. After all the above process the rotor looks as above. Now it has a pleasing look. Now the next part start. The above picture shows the winding overhang support. It is insulated using Fibre Glass tape. This has to be before starting rewinding. Now we are going to make the coils. Here we are using annealed copper strips of electrical grade for making rotor coils. These strips in various size comes in spools and
I am working at a small firm engaged in repairing and rewinding of electrical machines like Motors and Alternators. I am in this industry for the past 13 years. Here I am sharing some of my experience with AC Motors and Alternators. I hope it will be helpful to those in similar field and will help me when they share their experiences here.