# Fuses

A fuse is a short piece of metal, inserted in the circuit, which melts when excessive current flows through it and thus breaks the circuit. Continue reading

# Voltage Control

## Definition

The control of transmission voltage through adjustments in generator reactive output and transformer taps, and by switching capacitors and inductors on the transmission and distribution systems.

# Engineering quote week 10

Some Skills of Engineers

SOCIAL SKILLS

Engineers have different objectives when it comes to social interaction.

“Normal” people expect to accomplish several unrealistic things from
social interaction:

*Stimulating and thought-provoking conversation
*Important social contacts
*A feeling of connectedness with other humans

In contrast to “normal” people, engineers have rational objectives for
social interactions:

*Get it over with as soon as possible.
*Avoid getting invited to something unpleasant.
*Demonstrate mental superiority and mastery of all subjects.

# QP: Engineering Electromagnetics

## B.E. Sem-Vth Examination December 2010

Subject code: 151002

Subject Name: Engineering Electromagnetics

Date: 15 /12 /2010 Time: 03.00 pm – 05.30 pm

Total Marks: 70

Instructions:

1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Answer the following in brief

1. ‘The divergence of the curl of a vector is zero’-Justify the statement with one example.
2. Find the ay dot aɸ and ax dot aθ
3. Given 60 μC point charge located at the origin, find the total electric flux passing through that portion of the sphere r=26 cm bounded by 0˂θ˂π/2 and 0˂ɸ˂π/2.
4. For a coaxial cable find the electric field density inside the inner core, in between inner and outer core and outside the cable.
08

1. What is Gradient? with help of gradient prove that E= – V
2. Find the volume charge density that is associated with D = ρz2 sin2ɸ ap + ρz2 sinɸcosɸ aɸ + ρ2z sin2ɸ az c/m2
06
Q.2 (a) Derive the electric field intensity and electric field density due to an infinite and uniform line charge density. 07
(b) In the space, a line charge ρL=80 nC/m lies along the entire Z-axis, while point charge of 100 nC each are located at (1,0,0) and (0,1,0). Find the potential difference VPQ given P (2,1,0) and Q (3,2,5).

07
OR

(b) Given the flux density D = (2cosθ/r3) ar + (sinθ/r3) aθ c/m2, evaluate both sides of the divergence theorem for the region defined by 1˂ r ˂ 2 , 0 ˂ θ ˂ π/2 , 0˂ ɸ˂ π/2

07
Q.3 (a) Describe the boundary condition between free space and conductor. What is an importance of boundary condition? 07
(b) Write Maxwell’s equations in point form and explain physical significance of equations. 07
OR

Q.3 (a) Derive Poisson’s and Laplace’s equations and states their applications.

07
(b) Write Maxwell’s equations in integral form and explain their physical significance. 07
Q.4 (a) State and explain Ampere’s circuital law. Find the magnetic field intensity due to long straight conductor using Ampere’s circuital law. 07
(b) A charge of 10 nC is moving with a velocity of 107(-0.5 ax + ay -0.71 az) m/s. Determine the force exerted on the test charge when

1. a magnetic induction B = ( ax + 2ay + 3 az) mWb/m2 is applied
2. an electric field E = (3ax + 2ay + az) kV/m is applied.
3. When B and E given above are applied simultaneously.
07
OR

Q.4 (a) What is curl? With help of curl meter explain the physical interpretation of curl and state its applications.

07
(b) A filamentary current of 10 A is directed in from infinity to the origin on the positive x axis, and then back to infinity along the positive y axis. Use the Biot- Savart law to find H at P (0,0,1) 07
Q.5 (a) Define and explain the following terms:

1. Magnetization
2. Polarization
3. Skin effect and
4. Standing wave ratio
07
(b) Write short note on:

1. Wave motion in free space
2. Magnetic boundary condition
07
Or

Q.5 (a) Define and explain the following terms:

1. Poynting Vector
2. The scalar and Vector magnetic potential
3. Hall effect
4. Retarded Potential
07
(b) (i) Transform the 5ax vector to spherical coordinate at A(x = 2,y = 3, z = -1).

(ii) Given V = (10/r2 ) sinθcosɸ, Find the electric flux density at (2, π/2,0)

07

# QP: Microcontroller and Interfacing

## B.E. Sem-Vth Examination December 2010

Subject code: 151001

Subject Name: Microcontroller and Interfacing

Date: 13 /12 /2010 Time: 03.00 pm – 05.30 pm

Instructions: Total Marks: 70

1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) How Embedded Microcontrollers are differing than Embedding Microprocessor? Explain with technical justification and application.

07
(b) Explain RISC and CISC ? Which is most suited to Intel 51 Microcontroller? Why?

07
Q.2 (a) What is Special Function register (SFR) of 51-Microcontroller? List all the SFR and explain SBUF, IP and PCON.

07
(b) Describe and Draw Architecture of intel-51, 8-bit Microcontroller 07
OR

(b) Draw and Describe function of each pins of DIP-51 Intel 8-bit microcontroller

07
Q.3 (a) Explain following Addressing Modes of 8031 Microcontroller

1. MOV A,#20h
2. MOV A,30h
3. MOV A,@R0
4. MOVX A,@DPTR
5. MOVC A,@A+DPTR

07
(b) 1). Describe following pointers

1. PC
2. SP
3. DPTR
4. R0 & R1

2) What is flag register? Explain 8051 Flag register and its practical implementation

07
OR

Q.3 (a)

1). Differentiate ADDC and SUBB instruction. List the precaution to be taken for both instructions during the program.

2). List the JUMP and CALL instruction. Describe Conditional JUMP Instruction

07
(b)

1). What is Pseudo Codes? Explain it.

2). Define and describe the directives of 51 Microcontroller.

07
Q.4 (a)

1). Describe TMOD and TCON Special Function registers.

2). Write an assembly program to generate 10Khz Square wave frequency with 60%

duty cycle.(take T = 1.085 x 10-6 sec)

07
(b)

1). How will you assign Counter to count an external event? Explain it with example

2). Can We implement the interrupt to watch the TF bit of TCON Special Function

Register? Explain it.

07
OR

Q.4 (a) What is Serial Communication? How it will perform using 8051/52 Controller with PC? Explain it with program and diagram.

07
(b) Write an assembly as well as C program to transfer the message “ONE” serially at 9600 buad, 8-bit data, 1 stop bit. Perform this program for 255 times.

07
Q.5 (a)

1). Explain the difference between the low- level and edge-triggered interrupts

2). Explain which technique, Interrupt or Polling, avoids trying down the Microcontroller.

07
(b)

1) How Liquid Crystal Display (LCD) is superior to conventional Display? Explain it.

2). List and describe the LCD Instructions

Answer ti List of LCD Instruction

07
OR

Q.5 (a) Draw and Explain 8051 connection to ADC 0804 with self clocking mode.

07
(b) Draw and explain 8051 connection to external RAM (8Kx8). Write a program to read 100 bytes of data from P1 and save the data in external RAM starting at 5100H Location.

07

# QP: Electrical Power Engineering

## B.E. Sem-Vth Examination December 2010

Subject code: : 150801

Subject Name: Electrical Power Engineering

Date: 16 /12 /2010 Time: 03.00 pm – 05.30 pm

Total Marks: 70

Instructions:

1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.

Q.1 (a) Draw and explain the schematic arrangement of nuclear power plant. Also explain the functions of:

1. Moderator
2. Fuel rods
3. Control rods

07
(b) A 1 phase motor connected to 400V,50 Hz supply takes 25A at a p.f. of 0.65lag. Calculate the capacitance required in parallel with motor to raise p.f. to 0.90lag.  07
Q.2 (a) Define tariff and explain in detail:

1. Two- part tariff
2. Power factor tariff
3. Three-part tariff

07

6-10            30

10-12          45

12-16          60

16-20          40

20-24          30

07
OR(b) Calculate volume of conductor material used in

1. Overhead system, with 3wire dc system
2. Underground system, with 3 phase 3wire system

07
Q.3 (a) Explain string efficiency and methods of improving it. Answer Link
07

1. Critical disruptive corona voltage.
2. Visual corona voltage.

07
ORQ.3 (a) Explain FACTS devices.  07
(b) Explain different equipments used in substations with its symbols. 07
Q.4 (a) Define underground cables, draw and explain internal construction of it.  07
(b) A transmission line has a span of 100m between level supports. The conductor has cross-section area of 5cm2. The tension is the conductor is 2500 kg. If specific gravity of conductor material is 9.98m /cm3 and wind pressure is 1.2 kg/m. Calculate sag and vertical sag.  07
ORQ.4 (a) A part of transposition cycle of 3phase double circuit line is shown below. Radius of each conductor is 0.9cm.The conductors are made up of solid copper. Find the inductance/phase/km of the line.[image]  07
(b) Explain following in respect to medium transmission line.

• Nominal T method
• Nominal π method

07
Q.5 (a) Draw and explain following distribution schemes:

1. Secondary AC distribution system
3. Ring main distribution system

07
(b) Explain importance of voltage control and method to achieve it. 07
ORQ.5 (a) Differentiate most economical p.f. and most ideal p.f 02
(b) Explain:

1. Diversity factor
2. Plant capacity factor

05
(c) A two conductor street mains AB, 500 m in length is fed from both ends at 250 V. Loads 50 A, 60 A,40 A and 30 A are tapped at distance of 100 m, 250 m, 350 m, and 400 m from A respectively. If cross section area of the conductors be 1 cm2 and specific resistance of conductors is 1.7 × 10 -8 Ωm. Determine minimum consumer voltage. 07

A device which taps electrical energy from the electric power system is called a load on the system. The load may be resistive (e.g., electric lamp), inductive (e.g., induction motor), capacitive or some combination of them. The various types of loads on the power system are : Continue reading

# Assignment Three Phase Induction motor

Assignment 3: Three phase induction motor

1. Explain the equivalent circuit and Phasor diagram of three phase induction motor.
2. Discuss the procedure of no-load and blocked rotor test with test setup arrangement.
3. List out the basic steps of drawing the circle diagram with any one example.
4. Explain the unbalanced operation of the induction motor. Also discuss the case of single phasing.
5. Explain in brief about the cogging and crawling phenomena.
6. What are the desirable starting conditions for a three phase IM? Discuss all the starting methods with the circuit diagram.
7. Explain the construction, operation and equivalent circuit of double cage induction motor.
8. Discuss the methods of speed control of three phase induction motor.

Using circle diagram method, solve the followings:

1. Motor data: 3 phase, 20 HP, 440 Volt, 50Hz, 4 pole
2. No load test: 440 V, 10 A, 1.5 kW
3. Blocked rotor test: 120 V, 30 A, 2.25 kW
4. Determine   Full load current and PF & Maximum possible output power

1.  Motor data: 3 phase, 10 HP, 200 Volt, 50Hz, Slip ring IM, Rs = 0.38Ω and Rr = 0.24Ω  per phase, winding turns ratio unity
2. No load test: 200 V, 7.7 A, 0.195 pf
3. Blocked rotor test: 100 V, 47.6 A, 0.454 pf
4. Determine,   Starting & Maximum torque, Slip at maximum output and maximum output

1. Motor data: 3 phase, 40 HP, 440 Volt, 50Hz, 4 pole
2. No load test: 440 V, 16 A, 0.15 pf
3. Blocked rotor test: 100 V, 55 A, 0.225 pf
4. Ratio of rotor to stator copper losses is 0.9
5. Determine,   Full load current and PF & Maximum possible output power

1. Motor data: 3 phase, 15 HP, 230 Volt, 50Hz,Slip ring, Rs = 0.42 Ω and Rr = 0.3 Ω  per phase, winding turns ratio unity
2. No load test: 230 V, 9 A, 0.2143 pf
3. Blocked rotor test: 115 V, 45 A, 0.454 pf
4. Determine   Starting & Maximum torque & maximum output.

# Assignment Three Phase Transformer

Electrical and Electronics Engineering

Electrical Machines II

Assignment 2: Three Phase Transformers

1. Explain in brief about the construction of three phase transformer.
2. Draw all the vector group of transformer connection.
3. Discuss in brief about the application of the four basic types of connections of three phase transformer.
4. Discuss about the open delta connection and derive that the power transfer capacity is reduced by two third.
5. Explain about the scott connection. How three phase to two phase transformation is done?
6. Explain the parallel operation of the three phase transformers.
7. Discuss the harmonic phenomenon for three phase transformer.

Example:

Three 1100/110 V transformers connected in delta-delta supply a lighting load of 100kW. If one of the transformer is out of service, determine the following:

1. Current of each transformer in healthy condition.
2. Current of each transformer when one transformer is out of order.
3. kVA rating of each transformer if it supplies full load in open delta connection.

A 400 kVA load at 0.7 power factor lagging is supplied by three single phase transformers connected in ∆-∆ each. Each transformer is rated at 200 kVA, 2300/230 V. If one defective transformer is removed from service, calculate for the V-V connection,

1. kVA load carried by each transformer.
2.  Percent rated load carried by each transformer.
3.  Total kVA ratings of transformer bank in V-V.
4. Ratio of V-V bank to  ∆-∆ bank transformer ratings.
5. Percent increase in load on each transformer when one transformer is removed.

# Construction of cables

1. Core or Conductors
2. Insulators
3. Metallic sheath
4. Bedding
5. Armouring
6. Serving

Construction of cables