Question

an electric train weight 200tons has 8 motors from gear to driving wheel.each 90cm diameter.the torque developed to each motor to accelerate the train to a speed of 48km/hr is 30 sec of a gradient 1 in 200. the tractive resistance is 50N/tons. the fear ratio is 4 to 1. and efficiency 80%. the effort of rotational inertia is 10%​

Answer 1

*&%#77#489063@2++7#696%

Answer 2

Given :

Vm = 48km/hr

t = 30sec

D = 90cm = 0.9m

G = 1 / 200 = 0.5%

M = 200tons

r = 50 N/ton

Gear ratio = 1 : 4

η = 80% = 0.8

Rotational inertia = 10%

To find :

Torque produced by each motor

Solution :

∝ = Vm / t = 48 / 30 = 1.6km/hr/sec

Me = 1.1 × 200 = 220tons

Tractive effort Ft = 277.8 × ∝ × Me + 98 × M × G + M × r

Ft = 277.8 × 1.6 × 220 + 98 × 200 × 0.5 + 200 × 50

Ft = 97785.6 + 9800 + 10000

Ft = 117585.6 N

Ft = 2 r η T / D

117585.6 = 2 × 4 × 0.8 × T / 0.9

T = (117585.6 × 0.9) / ( 2 × 4 × 0.8)

T = 16535.475 Nm

Tm = T / 8

Tm = 16535.475 / 8

Tm = 2066.93 Nm

Therefore, torque produced by each motor is 2066.93 Nm.