Oil lubricant quality sensor for a lubricant supported electric motor and an oil cooled inverter

A quality diagnostics system for a lubricant/coolant fluid, comprising:

• a lubricant supported electric motor including a stator and a rotor defining a support chamber therebetween,
• a lubricant/coolant fluid disposed in the support chamber for supporting the rotor relative to the stator;
• an inverter including at least one electronic component configured to supply an alternating current (AC) power to the lubricant supported electric motor for driving the rotor to rotate relative to the stator;
• a passageway configured to convey the lubricant/coolant fluid from the support chamber of the lubricant supported electric motor and into direct contact with the at least one electronic component of the inverter;
• a lubricant quality sensor including a pair of first and second sensor plates disposed outside of and on opposite sides of the passageway,
• an excitation source configured to apply an AC excitation voltage to the first sensor plate,
• an electrical sensor disposed in communication with the second sensor plate and configured to measure a response to the AC excitation voltage and generate a sensor signal based on the measured response;
• and
• a controller disposed in communication with the electrical sensor and configured to determine, based on the sensor signal, at least one of metal contamination or water contamination in the lubricant/coolant fluid.