|
This report is a summary of the technical trends concerning the cooling system of a synchronous machine for the electric power, including various cooling systems, heat - temperature - ventilation analyses, and the cooling system maintenance, etc. In the synchronous machine, heats are generated in several parts such as copper loss of the armature and the field winding, iron loss of the armature core, and mechanical loss. To lower the temperature of the insulation materials below the thermal limits, these heats should be removed from the machine. In a large-machine like the generator for large electric power, advanced cooling technologies are indispensable. As the capacity and voltage of machines increase, the cooling becomes more difficult, because the ratio of internal heat generation to the surface area increase and the high voltage thick insulation causes higher thermal resistance. Cooling system of the synchronous machine has advanced from indirect cooling to direct cooling, from air cooling to hydrogen cooling or to water cooling. Recently, there has been a tendency to simplify the cooling system, such as from hydrogen cooling to air cooling system, or from water cooling to hydrogen cooling. In this report, the cooling method, the cooling design parameters, coolant temperature, problems on maintenance & inspection etc. are summarized in relation to synchronous generators manufactured domestically. |
