Motors and generators: Preventing moisture formation

The majority of induction motors and/or generators are installed in places characterized by the formation of moisture inside the machines due to environmental conditions. The amount of moisture formation will depend on many variables, and it is difficult to predict how much moisture will form. If this moisture is not removed or prevented, it can be harmful to the operation and reliability of the machines. It can shorten the winding insulation life, and the down time can be costly. This paper discusses conditions which contribute to moisture formation and in-depth discussion of various methods available to remove and/or prevent the formation of moisture. This text concentrates on a simple method using different types of heating elements, their selection, restrictions such as installation, surface temperature, applicable codes, requirements, etc. For motors and generators designed for operation in hazardous areas, using a heating element such as a space heater can reduce the risk of the motor igniting as the moisture will be removed from the winding insulation. Although these devices may seem small and insignificant, many variables may affect their use. The risk of improper usage can be high and potentially result in significant costs and delays during machine startup and commissioning.