ELECTRIC TRACTION – PART – 08 – QUADRILATERAL SPEED TIME CURVE & TWO PROBLEMS

PROBLEM -01

The following data relate to a 200 ton electric train running according to the following quadrilateral speed-time curve.

(1) Uniform acceleration from rest to the at 2kmphps for 30 sec.

(2) Coasting retardation for 50 sec.

(3) Duration of braking 15 sec.

(4) Up gradient – 1%

(5) Train resistance – 40 T/ton

(6) Overall efficiency of gear and motor – 75%

Find the schedule speed.

PROBLEM -02

An electric train accelerates uniformly from rest to a speed of 50 km/hr. It the coasts for 70 seconds against a constant resistance of 60 N/t and is then braked to rest with uniform retardation of 3 kmphps in 15 sec. Calculate 
(1) Uniform acceleration

(2) Coasting retardation

(3) Schedule speed if station stops are of 25 sec. duration. 
Allow 10% for rotational inertia. 

How will the schedule speed the affected if duration of stops is reduced to 20 seconds, other factors remaining the same?