Previous paper for NPTI

Please provide me question paper for National Power Training Institute examination soon ?

[Arun Vats]

Here I am giving you question paper for National Power Training Institute examination in a file attached with it

The armature resistance of a permanent magnet dc motor is 0.8 W. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A from the same source will be
Options A) 48.0% B) 57.1%

C) D) 88.8% 59.2% Correct Answer A 4 The solution of the first order differential equation x(t) = -3x(t), x (0) = x0 is Options A) x (t) = x0 e-3t B) x (t) = x0 e-3 x (t) = x0 e-1/3 D) x (t) = x0 e-1 C) Correct Answer A

5 The unit impulse response of a second order under-damped system starting from rest is given by c(t) = 12.5 e-6t sin 8 t, t 0 The steady-state value of the unit step response of the system is equal to Options
A) 0 B) 0.25 C) 0.5 D) 1.0 Correct Answer D 6

A single-phase, 230 V, 50 Hz, 4 pole, capacitor-start induction motor has the following stand-still impedances Main winding Zm = 6.0 + j4.0  Auxiliary winding Za = 8.0 + j6.0 

The value of the starting capacitor required to produce 90° phase difference between the currents in the main and auxiliary windings will be Options A) 176.84 F B) 187.24 FD) 280.86 F C) 265.26 F Correct Answer A 7