Project - Thermally Efficient Linear Motor

Thermally Efficient Linear Motor


Michael Liebman


Anorad Corporation

We analyze and design a high force per unit volume linear motor for use in machine tools. The motor is the first to incorporate coils wound with separated end-turns so that each layer of the coil can be directly cooled. Oil flows through the gaps in the end-turns on both sides of a coil to remove heat. A current of 1.6 A causes a 100°C temperature rise in a free convection-cooled coil; it takes a current of 9.0 A to cause the same temperature rise with our cooling technique. Thus our design allows nearly 6 times higher force in steady state and dissipates 32 times as much heat. We also investigate a second cooling scheme where we insert a comb-shaped piece of copper into the separated end-turn coil. Thermal analyses corroborated by experimental results are presented for both techniques.