Source: Tesla Tells Us How It Keeps Beating Nearly Everyone in Range Game Reducing waste in the powertrain increases range. The more efficient a motor, the more time an EV will stay on the road. Tesla told Car and Driver that the motor in the Model S has gone from 80 percent efficient to 90 percent, with peak efficiency at 94 percent during the EPA test cycles. According to Tesla, if you improve motor efficiency by 8 to 10 percent, the range will improve by 15 to 18 percent. Tesla also told us that its inverter (which takes DC energy and converts it to three-phase AC for the motor) is 96 to 97 percent efficient. At peak, the inverter is almost 99 percent efficient. Of course, there's still the matter of converting AC electricity to DC when plugged in to a Level 1 or 2 charger. Tesla didn't elaborate on that efficiency, which is also dependent on your local electrical infrastructure, but it's much less efficient than that. The use of an electric oil pump for the gearbox reduces energy usage by only spraying oil when needed. This is in addition to making the bearings and seals more efficient. A Tesla engineer told us that the company has spent the past 10 years building MATLAB models of where all the energy is flowing. From that, it's determined where the vehicles experience losses due to inefficiencies. The team then goes in and continually tweaks the hardware to increase efficiency. Additional secondary improvements can be pushed via over-the-air updates. Bob Wilson
Is the electricity path flowing the motors' bearings still an issue for longevity, power, and (I assume) efficiency? Or have they made progress there? Or not enough to worry about ATM (bigger fish to fry)?
Dang, I thought it was from something you had posted before. Yes, it concerned pitting and wear due to the flow path thru/around them. Edit: "When voltage accumulates on a motor shaft, it often finds the path of least resistance to ground via the motor bearings. This causes pitting on the bearing surfaces and ultimately leads to fluting of the raceways." Motor fluting: What is it and what causes it? I just picked this google search result at random. YMMV
I'll bet there's room to increase efficiency via parasitic loss when the vehicles remain capable night after night of receiving info from the Mothership. It'd also be nice to dial in chemistries that diminish the phenomena of slow leaking /capacity loss that naturally occurs when/if a car just sits there for a few days or longer, without being used.
I had posting something about it (+10 years ago?) but it was from an engineering magazine about poorly designed motors, especially induction motors. If the magnetic flux is not uniform across the rim of the motor, an asymmetrical field can induce a current between the two bearings. Then it becomes a failing arc generator ... very bad news. Bob Wilson
