BE Automobile Engineering सत्र १ (इंजीनियरिंग) - University of Mumbai Important Questions

In an R-L-C parallel circuit the current through the resistor, inductor(pure), and capacitor (pure) are 20A, 15A and 40A respectively. What is the current from the supply ?draw the phasor diagram.

Prove that the average power taking by a pure capacitor fed with a sinusoidal ac supply in a circuit is zero.

Derive the formula for resonant frequency of the circuit with a pure capacitor in parallel with a coil having resistance and inductance. Find the expression for dynamic resistance of this parallel resonant circuit.

A resistance and a capacitor connected in series across a 250V supply draws 5A at 50Hz. When frequency is increased to 60Hz, it draws 5.8A. Find the values of R & C. Also find active power and power factor in both cases.

A balanced 3 phase star connected load consists of three coils each consisting of R=6Ω and 𝑿𝑳= 8Ω . Determine the line current , power factor when the load is connected across 400V, 50Hz, supply

Find the node voltages 𝑽_𝟏,𝑽_𝟐 𝒂𝒏𝒅 𝑽_𝟑 and current through 0.5Ω

Draw the phasor diagram of a single phase transformer when it is loaded with a lagging power factor load.

A single phase transformer has 1000 turns on the primary and 200 turns on the secondary. The no load current is 3A at a power factor of 0.2 lag and the secondary current is 280A at a power factor of 0.8 lag. Neglect R₂ and X₂ calculate (1) Magnetizing component and loss component of no load current. (2) primary current (3) input power factor .Draw phasor diagram showing all the currents.

Describe the basic principle of operation of a single phase transformer and derive the emf equation.

The OC and SC test data are given below for a single phase, 5KVA, 200V/400V, 50Hz transformer

Determine the following :- 
1) Draw the equivalent circuit of the transformer referred to LV side.
2) At what load or KVA the transformer is to be operated for maximum efficiency?
3) Calculate the value of maximum efficiency.
4) Regulation of the transformer at full load 0.8power factor lagging.

Briefly explain the classification of DC machine.

state and prove varigon’s theorem.

Find the resultant of the force system as shown in the given figure.

Find the resultant of the force acting on the bell crank lever shown. Also locate its position with respect to hinge B.

Given : Forces on the bell crank lever
To find : Resultant and it’s position w.r.t hinge B

In the rocket arm shown in the figure the moment of ‘F’ about ‘O’ balances that P=250 N.Find F. 

Find the force F⁴ , so as to give the resultant of the force as shown in the figure given below. 

Given : Forces and their resultant
To find : Force F⁴

The resultant of the three concurrent space forces at A is 𝑹̅ = (-788𝒋̅) N. Find the magnitude of F1,F2 and F3 forces.

Given : A=(0,12,0)
            B=(-9,0,0)
           C=(0,0,5)
          D=(3,0,-4)
 Resultant of forces = (-788𝑗̅) N
To find : Magnitude of forces F1,F2,F3

A force of 140 kN passes through point C (-6,2,2) and goes to point B (6,6,8). Calculate moment of force about origin.

A machine part is subjected to forces as shown.Find the resultant of forces in magnitude and in direction.
Also locate the point where resultant cuts the centre line of bar AB.

Solution:
Given : A machine subjected to various forces
To find : Resultant of forces
             Point where the resultant force cuts the bar AB

Find the resultant of the parallel force system shown in Figure 1 and locate the same with respect to point C.