A lubricating and cooling fluid for an electric motor system comprising: a majority base oil of lubricating viscosity comprising an API Group III base oil, an API Group IV base oil, or mixtures thereof; at least one thiadiazole or hydrocarbyl-substituted derivatives thereof delivering 1000 to 1500 ppm sulfur to the lubricating and cooling fluid; an optional sulfurized ester delivering up to 300 ppm sulfur to the lubricating and cooling fluid; a dispersant system including (i) a first dispersant obtained from polyisobutylene having a number average molecular weight of 1500 to 2500 and delivering nitrogen in amounts of 700 ppm or less nitrogen to the lubricating and cooling fluid and (ii) a second dispersant obtained from polyisobutylene having a number average molecular weight of 1000 or less and delivering nitrogen in amounts of 150 ppm or less nitrogen to the lubricating and cooling fluid; an alkoxylated aliphatic amine delivering up to 20 ppm nitrogen to the lubricating and cooling fluid; an ether amine delivering up to 20 ppm nitrogen to the lubricating and cooling fluid; wherein at least one of the first dispersant and the second dispersant is borated and phosphorylated such that a total amount of boron and phosphorus in the dispersant system relative to the nitrogen in the dispersant system is from 0.5 to 0.7 and wherein the first and second dispersants deliver up to 100 ppm of total boron and phosphorus per 1000 number average molecular weight of the combined polyisobutylene moieties used in the dispersant system; wherein the average number molecular weight is determined by gel permeation chromatography using a polystyrene standard with a Mn of 180 to 18,000 as the calibration reference; wherein the lubricating and cooling fluid has an electrical conductivity of 60 nS/M or less, as measured by ASTM D2624-15 at 20 Hz and at 100 °C. a majority base oil of lubricating viscosity comprising an API Group III base oil, an API Group IV base oil, or mixtures thereof; at least one thiadiazole or hydrocarbyl-substituted derivatives thereof delivering 1000 to 1500 ppm sulfur to the lubricating and cooling fluid; an optional sulfurized ester delivering up to 300 ppm sulfur to the lubricating and cooling fluid; a dispersant system including (i) a first dispersant obtained from polyisobutylene having a number average molecular weight of 1500 to 2500 and delivering nitrogen in amounts of 700 ppm or less nitrogen to the lubricating and cooling fluid and (ii) a second dispersant obtained from polyisobutylene having a number average molecular weight of 1000 or less and delivering nitrogen in amounts of 150 ppm or less nitrogen to the lubricating and cooling fluid; an alkoxylated aliphatic amine delivering up to 20 ppm nitrogen to the lubricating and cooling fluid; an ether amine delivering up to 20 ppm nitrogen to the lubricating and cooling fluid; wherein at least one of the first dispersant and the second dispersant is borated and phosphorylated such that a total amount of boron and phosphorus in the dispersant system relative to the nitrogen in the dispersant system is from 0.5 to 0.7 and wherein the first and second dispersants deliver up to 100 ppm of total boron and phosphorus per 1000 number average molecular weight of the combined polyisobutylene moieties used in the dispersant system; wherein the average number molecular weight is determined by gel permeation chromatography using a polystyrene standard with a Mn of 180 to 18,000 as the calibration reference; wherein the lubricating and cooling fluid has an electrical conductivity of 60 nS/M or less, as measured by ASTM D2624-15 at 20 Hz and at 100 °C.