The trolleybus moves evenly and in a straight line at a speed of 27 km / h. The current in the motor winding is 40A

| August 5, 2021 | education

The trolleybus moves evenly and in a straight line at a speed of 27 km / h. The current in the motor winding is 40A, the voltage is 500V. Determine the efficiency of the electric motor. The mass of the trolleybus is 10 tons. The friction coefficient is 0.02.

Data: the trolleybus movement is uniform and straight; V (trolleybus speed) = 27 km / h (7.5 m / s); I (current in the motor winding) = 40 A; U (voltage) = 500 V; m (trolleybus mass) = 10 t (10 * 10 ^ 3 kg); μ (coefficient of friction) = 0.02.

Reference values: g (acceleration due to gravity) ≈ 10 m / s2.

The efficiency of the trolleybus electric motor is determined by the formula: η = N1 / N2 = Ftr * V / (U * I) = μ * m * g * V / (U * I).

Calculation: η = 0.02 * 10 * 10 ^ 3 * 10 * 7.5 / (500 * 40) = 0.75 (75%).



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