The subject matter disclosed herein relates to electrical machines. More specifically, the subject matter disclosed herein relates to liquid coolant flow through electrical machines.
A typical liquid cooled electric machine, in this case, a generator 100, is shown in FIG. 5. The generator 100 shown is dual-channel, having two rotors 102 and two stators 104. Each rotor 102 is surrounded by a stator 104 and an air gap 106 exists between each rotor 102 and each stator 104. Liquid coolant 108 is flowed through a hollow shaft 110 and is sprayed outwardly from the shaft 110 across rotor windings 112 and stator windings 114 to cool them and other components of the generator 100. The coolant 108 then is returned, via gravity, to a sump 116 of the generator 100. From the sump 116, the coolant exits the generator 100 through one or more scavenge ports 118 for recirculation through the system. Such liquid cooled generators 100 typically have poor coolant management leading to insufficient or slow scavenging leading to buildup of coolant levels in the sump 116. If the coolant level reaches the air gap 106, the result is greatly increased windage and friction losses as the rotor 102 rotates through the accumulated coolant 108. Such increased losses can lead to rotor and/or stator failure.