Design

• The design of an electrical motor has an impact on the amount of heat generated, as well as the motor's tolerance. Temperature distribution inside the electrical motor during operation is a key factor to long motor life. The more efficient the design of an electrical motor, the less heat is generated. For example, a three-phase machine with an efficiency near 90 percent produces less heat than a single-phase machine. The quality and quantity of insulation also affects the motor's resistance to heat.
  
  

Installation and Location

• An electrical motor's operating location has an effect on heat generation. Air flow will help to lower operating temperatures, along with installing the motor to minimize airflow resistance from factors such as excessive bends in the output piping.
  
  

Operation Overload

• Electrical motors have a load rating which can be exceeded during operation. This is referred to as a service factor. Multiplying the electric motor's horsepower by the service factor indicates how much the electric motor can be overloaded without overheating. Pushing an electrical motor beyond the rated service factor will generate additional heat. The overload on an electrical motor must take both voltage and current levels into account. Since voltage levels are rarely uniform, the heat caused by over-voltage will damage the electrical motor over time.
  
  

Lubrication and Cooling

• While an electrical motor does not have an internal lubrication system like an internal combustion engine, the bearing and rotating mass of the electrical motor must still be properly lubricated to avoid overheating and damage. This is particularly important in electrical motors since they can be overloaded to generate additional power.