Question

Consider an EV with the following details. Total mass = 1200 kg, front area = 2 m2, aerodynamic drag coefficient = 0.25 and tire rolling friction coefficient = 0.02, air density = 1.25 kg/m3, acceleration due to gravity = 10 m/s2. Equivalent mass for rotational mass can be taken as 6% of total mass. The wheel is connected to a three phase induction motor with a gear. Gear efficiency is 0.9. Induction motor is operating in constant torque region. The vehicle starts from rest and linearly reaches velocity of 80 km/hr in 10 seconds.1)Maximum acceleration of the vehicle isA)2.22 m/s2B)8 m/s2C)800 m/s2D)222.2 m/s21 point2)Aerodynamic drag at 10 sec isA)2000 NB)154.3 NC)25 ND)7 N1 point3)Rolling frictional force isA)240 NB)254.4 NC)278.4 ND)235.2 N1 point4)Tractive effort at 10 sec isA)3218.1 NB)3058.3 NC)10570.3 ND)3232.54 N1 point5)Power at the wheels isA)7144 WB)64.4 kWC)6429.6 WD)71.5 kW1 point6)Power at the motor shaft isA)71.56 kWB)6429.6 WC)79.5 kWD)7937.78 W1 point7)Percentage grade of the vehicle isA)26.2B)27.8C)26.36D)24.771 point8)If gear ratio is increased by twice, the new tractive effort will beA)6436.3 NB)1609.07 NC)6116.6 ND)1529.15 N1 point9)Speed of the motor at 3 seconds isA)24 m/secB)2400 m/secC)666.6 m/secD)6.7 m/sec1 point10)Tractive effort at 5 seconds isA)2942.5 NB) 3218.13 NC) 3102.3 ND) 3058.3 N​

Answer 1

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