Can some of you engineer types help to clear this up for me?
A Tesla mobile technician told me that M3 dual motor gets less range than single motor because torque sleep is impossible when one motor is permanent magnet type. According to him, the PM motor cannot free-wheel, so it must either drive or regen whenever the car is moving. For that reason, he said, the car cannot be towed. In "tow mode", software allows just 20 minutes to move the car (to the side of the road or onto a flat bed, for instance) before the parking brake automatically sets itself.
It would seem to me that, even in permanent magnet motors, when there is an open circuit there should be no EMF. What am I missing?
A Tesla mobile technician told me that M3 dual motor gets less range than single motor because torque sleep is impossible when one motor is permanent magnet type. According to him, the PM motor cannot free-wheel, so it must either drive or regen whenever the car is moving. For that reason, he said, the car cannot be towed. In "tow mode", software allows just 20 minutes to move the car (to the side of the road or onto a flat bed, for instance) before the parking brake automatically sets itself.
It would seem to me that, even in permanent magnet motors, when there is an open circuit there should be no EMF. What am I missing?