1. Upgradation Control system of Double Column Vertical Boring and
Turning Mill-01
using
Variable Frequency Drive
Author
Sajid IRan Khan
16F-MS-EE-15
Focal Person
Mr. Habib Ur Rehman Habib
DEPARTMENT OF ELECTRICAL ENGINEERING
FACULTY OF ELECTRICAL ENGINEERING
UNIVERSITY OF ENGINEERING AND TECHNOLOGY TAXILA
JAN-2017

2. i
Upgradation Control system of Double Column Vertical Boring
and Turning Mill-01
using
Variable Frequency Drive
Author
Sajid IRan Khan
16F-MS-EE-15
A Report submitted in partial fulfillment of the requirement for the visit of
Heavy Mechanical Complex Taxila
Focal Person
Mr. Habib Ur Rehman Habib
Lab Engineer, Electrical Engineering
Chairman’s Signature: _____________________________________________
Focal Person’s Signature:______________________________________________
DEPARTMENT OF ELECTRICAL ENGINEERING
FACULTY OF ELECTRICAL ENGINEERING
UNIVERSITY OF ENGINEERING AND TECHNOLOGY TAXILA
JAN-2017

3. ii
ABSTRACT
Double Column Vertical Boring and Turning Mill-01 is a universal heavy duty boring
and turning mill, used for machining parts made of steel, cast iron and non-ferrous metals.
For Double Column Vertical Boring and Turning Mill-01, A DC Motor drive is used to
rotate a rounding table for turning and boring of a given job e.g. wheel gear. To Control
the speed of DC motor drive a Ward Leonard control system is used which a lot of
disadvantages such as system is very costly because two extra machines (motor-generator
set) are required and overall efficiency of the system is not sufficient especially if it is
lightly loaded. To provide a best control system for Double Column Vertical Boring and
Turning Mill-01, we referred Variable frequency drive to replace the Ward Leonard
control system. So for that purpose we will replace DC motor with 75KW AC Spindle
Servo Motor and Control its speed and torque through Variable frequency drive.
Keywords: Double Column Vertical Boring and Turning Mill, Variable Frequency Drive

4. iii
UNDERTAKING
Use the following undertaking as it is.
I certify that research work titled “Upgradation Control system of Double Column
Vertical Boring and Turning Mill-01 using Variable Frequency Drive” is my own work.
The work has not been presented elsewhere for assessment. Where material has been
used from other sources it has been properly acknowledged / referred.
Signature of Student
16F-MS-EE-15
Engr SI Khan

5. iv
ACKNOWLEDGEMENTS
I humbly thank Allah Almighty, the Merciful and the Beneficent, who gave me health,
thoughts, co-operative people, and enabled me to achieve this goal.
I am highly thankful to focal person Mr. Habib Ur Rehman Habib, Lab Engineer,
Electrical Engineering Department, University of Engineering and Technology Taxila,
for his kind and continuous help, guidance and encouraging attitude during the
preparation of this report, from the start to the completion, he has been generous to spare
his precious time for discussion and doing away with difficulties arising at various stages.
It can safely be assumed that working under his guidance is nothing short than an asset
which will remain a light tower throughout my life.
I am also grateful to Mr. Khalid Mehmood Shah, Manager at Heavy Mechanical
Complex Taxila for giving me access to all relevant Machine and provide all relevant
information about my project.
At the end especially thanks to staff of Electrical Department of Machine Assy. &
Auxiliary Shop for their co-ordination and meaning full guidance during that period.

6. v
TABLE OF CONTENTS
Abstract ............................................................................................... ………...ii
Acknowledgement ..............................................................................................iii
List of Figures .....................................................................................................vi
List of Tables......................................................................................................vii
Abbreviations....................................................................................................viii
Chapter I: Introduction...................................................................................8
1.1: Double Column Vertical Boring and Turning Mill-01...........8
1.2: Working Operation perform by VBT-01................................9
Chapter II: Existing Control System for VBT………………………...…..10
2.1: Existing Control System........................................................10
2.2: Block Diagram of Existing Control system..........................12
2.3: Other AC Motors using in VBT-01 ......................................12
2.4: Block Diagram For Different Motors in VBT......................13
Chapter III: Proposed Control System……………………………….…...14
3.1: Problem Identification...........................................................14
3.2: Proposed Solution..................................................................14
3.3: Comparison AC Spindle Servo Motor over DC Motor........16
3.4: Variable Frequency Drive .....................................................17
3.5: Variable Frequency Drive Operating Principle ....................17
Chapter IV: Conclusions & Recommendations……………………...…...19
Chapter V: References……………………….…………………..……...20

7. vi
LIST OF FIGURES
Number Page
Fig 1.1 View of Vertical Boring and Turning Mill-01……………....…..9
Fig 1.2 Different parts of Vertical Boring and Turning Mill-01..............10
Fig 2.1 Generator Motor Set....................................................................11
Fig 2.2 Control Panel of DC Motor Drive ...............................................12
Fig 2.3 View of DC Compound Motor....................................................12
Fig 3.1 75KW AC Spindle Servo Motor. ................................................15
Fig 3.2 Small variable-frequency drive. ..................................................17

8. vii
LIST OF TABLES
Number Page
Table 2.1 Specifications of MG-Set ……………....………….………...11
Table 2.2 Rating DC Compound Motor …… .........................................12
Table 3.1 Specifications of 75KW AC Spindle Servo Motor.............….15

9. 8
CHAPTER 1
Introduction
1.1 Double Column Vertical Boring and Turning Mill-01
Double Column Vertical Boring and Turning Mill-01 is a universal heavy duty boring and
turning mill, used for machining parts made of steel, cast iron and non-ferrous metals. It is
used for tuning cylinders, cones and plane surfaces by means of high speed steel tool or
carbide tool, and is serviceable both for roughing and finishing. Complete view of Double
Column Vertical Boring and Turning Mill-01 is given below in fig 01.
Fig 1.1: View of Double Column Vertical Boring and Turning Mill-01
Type: C5240
Shop: Machine Assy. & Auxiliary Shop
Serial No: 22
Manufactured By: Wuhan Machine Tool Works

10. 9
1.2 Working Operation perform of Vertical Boring and Turning Mill-01
Vertical boring machine is use for large, heavy work parts through large diameters;
frequently the work part diameter is more than its length. The Part is clamp to workable that
rotates relative to machine base. Worktables able to 40 it in diameter are accessible. Typical
boring machine can place and feed several cutting tools at the same time. Tools are mounted
on toll heads that can be fed horizontally and vertically relative to worktable. One or two
heads are mounting on horizontal cross-rail assemble to machine tool housing over the
worktable. Cutting tools mount over the work can be used for lacing and boring. In adding to
tools on cross-rail, one or two extra tool heads can mount on side columns of housing to
enable revolving on outside diameter of work.
Fig 1.2: Different parts of Double Column Vertical Boring and Turning Mill-01

11. 10
CHAPTER 2
Existing Control System for Vertical Boring and Turning Mill
2.1 Existing Control System
The electrical equipment of this machine consists of control desk, three electrical control
cabinets, M-G set etc.
Power Supply 360V, 50Hz
The Drive of the table is realized by means of a generator-motor automobile speed
adjustment system controlled by SCR with the speed of 200-750-1500 r.p.m. The drives of
left & right tool heads are realized by means of AC electrical shaft. The servo speed is 35-618
r.p.m. sufficient protecting interlocks and signal indicating devices are provided for all the
electrical equipment so as to ensure the safety and reliability of the operation.
Ward Leonard control system is introduced by Henry Ward Leonard in 1891.
For DC drive speed control, variable-voltage DC supply needed for speed control of an
industrial DC motor was to generate it with a DC generator. The generator was driven at
fixed speed by an induction motor, and the field of the generator was varied in order to vary
the generated voltage. So for that purpose pulse transformer provide pulse signal to SCR
where SCR will provide required dc voltage to field of generator.
Fig 2.1: Generator Motor Set

12. 11
Table 2.1: Specifications of MG-Set
DC Generator Induction Motor
Type: Z2-101
90 KW
230V, 392A
1450 r.p.m
Separately excited:
110/220 V
Type: J0-94-4
100KW
660/380 V
1450 r.p.m
180 A
Fig 2.2: Control Panel view using SCR to control Speed of DC Motor Drive
Fig 2.3: View of DC Compound Motor

13. 12
Table 2.2: Rating DC Compound Motor
2.2 Block Diagram of Existing Control system
2.3 Other AC Motors using in Vertical Boring and turning Mill-01
Air Pump Motor
Type: JO2-21-2 (3M)
1.5 KW
2850 r.p.m
380 V 3.22A
Lubricating Oil Pump Motor
Type: JO2-41-4 (D2/T2) (4M)
4.0 KW
1440 r.p.m
380 V 8.40 A
Speed Change Box Oil Pump Motor
Type: JO2-22-6 (D2/T2) (5M)
1.1 KW
930 r.p.m
380 V 3.01 A
Cross Rail Travel Motor
Type: JQO2-52-4 (D2) (6M)
10 KW
1450 r.p.m
380 V 20.35
Cross Rail Left Clamping Motor
Type: JO2-22-6 (D2) (7M)
1.1KW
930 r.p.m
380 V 3.01 A
Cross Rail Right Clamping Motor
Type: JO2-22-6 (D2) (8M)
1.1KW
930 r.p.m
380 V 3.01 A
DC Compound Motor
Type: Z2-111
75 KW
220 V, 387 A
750/1500 r.p.m
Induction
Motor
Dc
Generator
DC Motor
Drive
Control System
(SCR + Pulse Transformer)

14. 13
2.4 Block Diagram of Control Circuit for Different Motors in VBT
ZD Automatic Switch
Dz1-600/330
Compound Trip
Current 250 A
G-1M
A.C Contactor
CJ1-300A/3
Coil Voltage 380 V
ZD 3M Automatic
Switch Dz4-25/330
Compound Trip
Current 25 A
G-3M
A.C Contactor
CJO-20
Coil Voltage 110 V
ZD 4M Automatic
Switch Dz4-25/330
Compound Trip
Current 10 A
G-4M
A.C Contactor
CJ0-20
Coil Voltage 110 V
G-5M
A.C Contactor
CJ0-10
Coil Voltage 110 V
G-6M
A.C Contactor
CJ0-40
Coil Voltage 110 V
G-7M
A.C Contactor
CJ0-10
Coil Voltage 380 V
G-8M
A.C Contactor
CJ1-300A/3
Coil Voltage 380 V
ZD 5M Automatic
Switch Dz4-25/330
Compound Trip
Current 4 A
ZD 6M Automatic
Switch Dz4-25/330
Compound Trip
Current 25 A
ZD 7M Automatic
Switch Dz4-25/330
Compound Trip
Current 4 A
ZD 8M Automatic
Switch Dz4-25/330
Compound Trip
Current 4 A
3M
380V A.C
Circuit Breaker Magnetic Contactor
380/110V
380/110V
380/110V
380/110
380/110
V
V
380/110V
380/110V
1M
4M
5M
6M
7M
8M
Motor

15. 14
CHAPTER 3
Proposed Control System
3.1 Problem Identification
For Double Column Vertical Boring and Turning Mill-01, A DC Motor drive is used to rotate
a rounding table for turning and boring of a given job e.g. wheel gear. To Control the speed
of DC motor drive a Ward Leonard control system is used which has following
disadvantages:
1. The system is very costly because two extra machines (motor-generator set) are
required.
2. Overall efficiency of the system is not sufficient especially if it is lightly loaded.
3. Larger size and weight. Requires more floor area.
4. Frequent maintenance.
5. The drive produces more noise.
6. Signal interrupted in case of pulse transformer burn or fault in SCR.
3.2 Proposed Solution
To provide a best control system for Double Column Vertical Boring and Turning Mill-01,
we referred Variable frequency drive to replace the Ward Leonard control system. So for that
purpose we will replace DC motor with 75KW AC Spindle Servo Motor and Control its
speed and torque through Variable frequency drive.
Fig 3.1: 75KW AC Spindle Servo Motor

16. 15
Table 3.1: Specifications of 75KW AC Spindle Servo Motor
3.3 Comparison AC Spindle Servo Motor over DC Motor
AC Spindle Servo Motor
1. Low power output of about 0.5 W to 100 W
2. Efficiency is less about 5 to 20 %
3. Due to absence of commentator maintenance is less
4. Stability problems are less
5. No radio frequency noise
6. Compare to DC servo motor it is relatively stable and smooth operation
7. AC amplifier used have no drift
DC Compound Motor
1. Deliver high power output
2. High efficiency
3. Frequent maintenance required due to commentator.
4. More problems of stability
5 Brushes produce radio frequency noise.
6. It is noisy operation
7. DC amplifier used have a drift

17. 16
3.4 Variable Frequency Drive
A variable-frequency drive (VFD) (also termed adjustable-frequency drive, variable speed
drive, AC drive, micro drive or inverter drive) is a type of adjustable-speed drive used in
electro-mechanical drive systems to control AC motor speed and torque by varying motor
input frequency and voltage. VFDs are used in applications ranging from small appliances to
the largest of mine mill drives and compressors.
However, around 25% of the world's electrical energy is consumed by electric motors in
industrial applications, which are especially conducive for energy savings using VFDs in
centrifugal load service, and VFDs' global market penetration for all applications is still
relatively small. That lack of penetration highlights significant energy efficiency
improvement opportunities for retrofitted and new VFD installations.
Over the last four decades, power electronics technology has reduced VFD cost and size and
has improved performance through advances in semiconductor switching devices, drive
topologies, simulation and control techniques, and control hardware and software.
Small variable-frequency drive is shown in fig 07.
Fig 3.2: Small variable-frequency drive
3.5 Variable Frequency Drive Operating Principle
Whilst there are a number of variations in variable frequency drive design; they all offer the
same basic functionality which is to convert the incoming electrical supply of fixed frequency
and voltage into a variable frequency and variable voltage that is output to the motor with a
corresponding change in the motor speed and torque. The motor speed can be varied from
zero rpm through to typically 100-120% of its full rated speed whilst up to 150% rated torque
can be achieved at reduced speed. The motor may be operated in either direction.
Variable frequency drives applied to AC motors are by far the most common. Their basic
design consists of four elements:
 Rectifier: the working principle of rectifier is changing the incoming alternating
current (AC) supply to direct current (DC). Different designs are available and these
are selected according to the performance required of the variable frequency drive.
The rectifier design will influence the extent to which electrical harmonics are
induced on the incoming supply. It can also control the direction of power flow.

18. 17
 Intermediate circuit: the rectified DC supply is then conditioned in the intermediate
circuit, normally by a combination of inductors and capacitors. The majority of VFDs
currently in the marketplace use a fixed-voltage DC link.
 Inverter: the inverter converts the rectified and conditioned DC back into an AC
supply of variable frequency and voltage. This is normally achieved by generating a
high frequency pulse width modulated signal of variable frequency and effective
voltage. Semiconductor switches are used to create the output; different types are
available, the most common being the Insulated Gate Bipolar Transistor (IGBT).
 Control unit: the control unit controls the whole operation of the variable frequency
drive; it monitors and controls the rectifier, the intermediate circuit and the inverter to
deliver the correct output in response to an external control signal.
Variable frequency drives are typically 92-98% efficient with 2-8% losses being due to
additional heat dissipation caused by the high-frequency electrical switching and the
additional power required by the electronic components. Equally motors connected to
variable frequency drives experience some additional losses due to heating caused by the
high frequency electrical switching.

19. 18
CONCLUSIONS & RECOMMENDATIONS
For Vertical Boring and Turning Mill-01, A DC Motor drive is used to rotate a rounding table
for turning and boring of a given job e.g. wheel gear. To Control the speed of DC motor drive
a Ward Leonard control system is used which has a lot of disadvantages. To provide a best
control system for Double Column Vertical Boring and Turning Mill-01, we referred
Variable frequency drive to replace the Ward Leonard control system. So for that purpose we
will replace DC motor with 75KW AC Spindle Servo Motor and Control its speed and torque
through Variable frequency drive.
Proposed Control system will provide following advantages:
 This will Energy savings.
 Elimination of expensive mechanical drive components.
 Increased motor longevity.
 Reduced power line disturbances.
 Reduced risk of motor damage during start up and stop.

20. 19
REFERENCES
Citations
1) Kulkarni, A.B. (Oct 2000). "Energy consumption analysis for geared elevator modernization:
upgrade from DC Ward Leonard system to AC vector controlled drive". Conference Record
of the 2000 IEEE Industry Applications Conference. 4. Institute of Electrical and Electronics
Engineers. pp. 2066–2070.
2) "Electrically propelled Vehicle", H.W. Leonard, US Patent 1121382, originally filed March,
1903
3) Shinners, Stanley M (1998). Modern Control System Theory. Wiley and Sons. p. 202.
ISBN 978-0471249061.
4) Rajput, R.K. (2005). Basic Electrical Engineering. Laxmi Publications Pvt Limited. p. 571.
ISBN 9788170081203. Retrieved 2014-06-14.
5) Datta, A.K. (1973). "Computerless optimal control of Ward Leonard drive system".
International Journal of Systems Science. 4 (4): 671–678. doi:10.1080/00207727308920047.
General references
1) The Editors (Nov 1989). "Technology for Electrical Components". Power Transmission
Design: 25–27.
2) Ward Leonard, H. (1896). "Volts versus ohms - the speed regulation of electric motors". AIEE
Trans. 13: 375–384.
3) Gottlieb, I.M. (1994). "Electric Motors & Control Techniques 2nd Edition". TAB Books.
4) Malcolm Barnes (2003). Practical Variable Speed Drives and Power Electronics. Oxford:
Newnes. pp. 20–21. ISBN 978-0-7506-5808-9.
5) Campbell, Sylvester J. (1987). Solid-State AC Motor Controls. New York: Marcel Dekker, Inc.
pp. 79–189. ISBN 0-8247-7728-X.
6) Jaeschke, Ralph L. (1978). Controlling Power Transmission Systems. Cleveland, OH:
Penton/IPC. pp. 210–215.
7) Siskind, Charles S. (1963). Electrical Control Systems in Industry. New York: McGraw-Hill,
Inc. p. 224. ISBN 0-07-057746-3.
8) NEMA Standards Publication (2007). Application Guide for AC Adjustable Speed Drive
Systems. Rosslyn, VA USA: National Electrical Manufacturers Association (now The
Association of Electrical Equipment and Medical Imaging Manufacturers). p. 4. Retrieved
Mar 27, 2008.
9) Bose, Bimal K. (2006). Power Electronics and Motor Drives : Advances and Trends.
Amsterdam: Academic. p. 22. ISBN 978-0-12-088405-6.
10) Bartos, Frank J. (Sep 1, 2004). "AC Drives Stay Vital for the 21st Century". Control
Engineering. Reed Business Information.
11) Eisenbrown, Robert E. (May 18, 2008). "AC Drives, Historical and Future Perspective of
Innovation and Growth". Keynote Presentation for the 25th Anniversary of The Wisconsin
Electric Machines and Power Electronics Consortium (WEMPEC). University of Wisconsin,
Madison, WI, USA: WEMPEC. pp. 6–10.
12) Jahn, Thomas M.; Owen, Edward L. (Jan 2001). "AC Adjustable-Speed Drives at the
Millennium: How Did We Get Here?". IEEE Transactions on Power Electronics. IEEE. 16
(1): 17–25. doi:10.1109/63.903985

21. viii
ABBREVIATIONS
HMC: Heavy Mechanical Complex Taxila
VBT: Vertical Boring and Turning Mill
VFD: Variable Frequency Drive
A.C: Alternating Current
D.C: Direct Current
R.P.M: Revolutions per minute