Name of the project
The name of the
project done by me is Design and Implementation of Automatic Changeover Circuit
for UPS to switch from one UPS to another to maintain an uninterrupted power
supply to controllers, PLCs and network switches connecting them through
Duration of the project
The project was
done during the period from 20 January 2015 to 27 January 2015 as the project
could be done only on the shutdown maintenance day.
Organization and geographical location
The project was
done at MRF Tyres Limited, Ankenpally,
Telengana, India, which started
as a rubber balloon manufacturing unit and has later turned out to become a
tire manufacturing company, producing quality tires all over India and
internationally besides its presence in paints, coats, toys, motorsports and
Position occupied by me in the project
I was holding
the position of Electrical Maintenance Engineer during the project with the
responsibility of implementing machine modifications and control system design
using both hardwire and software applications.
Nature of the project
arose when the continuous power delivered by the available backup power supply
was insufficient and uncertain as there were chances of breakdown of the backup
system. As the controllers, PLCs, network switches and hubs which connected
PLCs to other devices through ethernet and SCADA played a crucial role in the tire
manufacturing process of the plant, it was extremely important to have an
additional backup as the manufacturing process could not be compromised for power
fluctuations and interruptions including UPS failure or breakdown. The company
took the assistance of Shiva Erectors and SVS Contractors for the adequate
manpower for the project under my leadership and supervision.
Objective of the project
As discussed by
the engineering team of our manufacturing unit lead by the Engineering Manager,
it was decided to provide an additional backup supply for the SCADA equipment
in order to ensure the uninterrupted power supply for all equipment and
maintaining the ongoing tire manufacturing operations during occasions of power
interruption or UPS emergency shutdown.
Nature of work
The team of 15
members allocated for the project comprised of two high skilled technicians,
five skilled, five semi-skilled and two unskilled contract laborers. Except for
some cable laying work, the major part of the work was in and around SCADA and
UPS rooms. The whole work was comprised of two major phases.
Phase-1 included study of
electrical parameters like total load on the UPS, estimation of cable
requirement, design of control circuit and selection of protective devices and
control circuit elements.
Phase-2 incorporated planning
and scheduling of daily jobs, manpower allocation for the job, distribution of
jobs to each member of the group and supervision and monitoring of jobs to
ensure its completion within stipulated time.
role in the project
tenure of the project, I was entrusted with many responsibilities listed as
I have referred to technical
information and technical standards for selection of cables, wiring methods and
switching control equipment. I was confident in volunteering myself to take up
the responsibility of the project during the department level meeting and
agreed to complete the meticulous and tiresome work within the deadline.
I have estimated the
requirements like the cable length, contactor, auxiliary contact, timer relay,
switching relay, rectifier and so on using the technical standards and
geographical location of existing panels.
Conducted study on the existing
load of the intended equipment on UPS by isolating it. This was to analyze the
current and voltage before selection of protective devices that have to be kept
for the new modification.
Designed the control circuit
and specifications and prepared electrical circuit diagram of the same for
reference while working.
Coordinated with the Assistant
Manager on the allocation of manpower based on the skill and experience for
completion of the project.
Organized the allocated
manpower according to their skill, experience and divided them according to the
nature of work as planned.
Ensured safe working conditions
throughout the duration of work by following the safety procedures and
Allocated work to different
sub-groups and provided training and instruction to each group on the nature of
work they are intended to do. This helped to avoid mishaps during the entire
course of work.
Monitoring and supervision of
work like cable laying, control wiring, ensuring the presence of skilled and
experienced workers in each electrical related work besides the semi-skilled to
ensure the reliability of work done by each team.
Testing was done by isolating
the backup UPS on which the load was on. The load immediately shifted to the
standby UPS successfully. Once the initial UPS was turned on, the load shifted
to that backup supply after manual shifting of load using a switch.
Reported the progress of the
project at each stage to the Assistant Manager, prepared report and detailed
the project and its scope to the Engineering Manager during the weekly
Reported the same in the daily
log and task register for future reference and was documented in the OSHAS as a
fatigue reduction modification.
Regular testing and
verification was conducted on every plant shutdown occasions to ensure its
healthy operation and safe condition of control equipment.
C.E 1.2.5 Organizational
Application of Engineering Knowledge
changeover unit was based on the principle of Electromagnetism. When an
electric voltage (AC/DC) of the specified value is applied across the
energizing coils of the switching device which is an electromagnet, the magnetic
field thus generated attracts the moving core of the switch thus activating the
respective contacts. It develops force which holds the moving and fixed contacts
together. The corresponding contact positions (Normally Closed/Normally Open)
change to opposite states (Open/Closed) respectively.
electromagnet or coil is de-energized, the pulling force vanishes and the
spring connected to the core returns the core with the contacts to its initial
positions. Thus, the switches like relays and contactors operate on this
principle for electromagnetism for the necessary output. The timer based relays
also work on the same principle but after a set time interval. The control coil
wiring and the wiring of various Normally Open (NO) and Normally Closed (NC) contacts
were done as per the auto- changeover logic to enable timer based switching
from one backup UPS supply to the standby UPS supply after two seconds, in case
of any mishaps.
The cable laying
and wiring with the overvoltage and overcurrent protection are done as per the
IS.732 – 1989 and the wiring systems such as perforated trays and ladder wiring
system were done. The marking and identification of the power cables and
control cables were done as per the IS: 11353- 1985 with the respective color
coding like red, yellow, blue, black, green and yellow for U, V, W, N and PE
The safety of
workers was considered throughout the project complying to the IS:
5216(Part-1)-1982 which acts as a guide for safety practices and regulations in
electrical work. The power supply isolation from the UPS outgoing was done
along with the shutdown of UPS as per procedure were done and lockout with
lockout tag was done to ensure the safe working conditions during cable laying
and termination at both ends of the cable.
5133(Part-1)-1969 was referred to while selection of panel box for the Auto-changeover
circuit and cast-iron box was selected for the enclosure of electrical
accessories. The cast-iron box of dimensions 500mm x 300mm was selected to
incorporate the control and protection devices.
switches and switching equipment for control and auxiliary circuits including
contactor relays and its general requirements and tests as per the IS:
6875(Part-1)-1973 and IS:2959 – 1985 was considered while selecting the
switching contactors, timer contacts and relay switches.
Tasks delegated and accomplished
backup UPS supply, along with the present one, was discussed by a team of
higher-ups including the Plant Head at the topmost level followed by the Plant
Engineering Manager who is, in turn, assisted by the Assistant and Deputy
Managers of the respective departments who finally entrust the responsibility
to their engineers who are assisted by skilled or semi-skilled electrical
activity that I did was to study the various electrical parameters like
available power supply voltage and load on 300kVA UPS. Voltage supply was found
within normal range of 410V AC between phases and the total load in each phase
of the three-phase supply was around 8 amperes. Considering the future loads
that are planned to be connected to the UPS, the total intended load was
calculated as 8 amperes. For protection, MCB of rating 10 amperes was selected
for both the backup UPS incoming sides. The estimation was done to determine
the size and length of the cable that has to be laid based on the location of
UPS outgoing panels and the SCADA room. Armored cable of 2.5sq.mm and 40-meter
length was used to connect common panel with the UPS outgoing cables.
routing was done and perforated cable trays were laid in the intended route for
the cables. Junction box and control box were fixed at the planned positions.
Cable glanding and termination was done at both sides of the cable and the
control box. The cables on the cable tray and panel box were properly dressed
and identified. I selected control switching components as per the current
rating of the switching devices. The ambient temperature specification was
maintained at 20 – 30 degrees using air conditioners for SCADA panels and PLCs
inside SCADA room.
I designed the
control circuit based on the logic of automatic switching such that under
normal conditions, the supply would be from the first 300kVA UPS. In case of a
breakdown or failure of the UPS, the power supply delivered by the UPS cuts
off. This will engage the power contactor of second UPS to deliver power to the
controllers thereby maintaining an uninterrupted power supply to the SCADA room
equipment. Once the interruption for the first UPS is removed and ready to
deliver power, switching is done to the first UPS from the second one by means
of manual intervention through a switch. The power and control cables were
properly dressed and terminated at both ends and inside panels with adequate
identification and safety warning. I split and distributed the entire job among
the workers after proper planning and organization so that work can be carried
out simultaneously and completed on the same day.
Problems encountered and solutions implemented
Problem – 1
foremost, the major challenge that I faced in the project was that it had to be
completed and verified on the first day and second day could be used only for
any auxiliary works as this job could be done only on the plant shutdown days
which usually falls on public holidays in India.
was done to combat the challenge. The high skilled and skilled workers were
employed on the first day along with the skilled contract workers so that the
works that demands skill and experience could be accomplished on the first day.
The semi-skilled workers were arranged on the net day for the permanent fixing
and anchoring of support structures.
Problem – 2
faced by me during this time was that it was difficult to wire up the control
elements in either of the UPS outgoing panel side as both were far away from
each other. The estimated length became insufficient to serve the purpose.
I came to a
solution to the problem by including an additional panel which would act as the
common panel for both the UPS outgoing cables and as a control panel thereby
reducing the required length of the cable.
Problem – 3
problem that I had to face during the work was that some workers were reluctant
to do their assigned jobs and some others who were planned for the work did not
show up on the day.
This has made me
to reorganize the work making up for the absentees and shuffling workers and
assigning jobs to them based on their interests in doing the job. This has
resulted to be extremely successful as the workers were motivated and has led
to the completion of job on time. I monitored and supervised the entire job to
ensure that they are carried out as planned and designed meeting the
requirements with perfection and minimum wastage of resources.
C.E.1.4.1 My overall view on the project
Even though the
task taken up by me was timebound and stressful, it has improved my confidence
and has helped me to push my limits forward to take up responsibilities
courageously and accomplish it using my technical skills and knowledge.
C.E.1.4.2 Requirements met by the project
It has been
implemented as per the intended concept and plan and has ensured one hundred
percent uninterruptable power supply for SCADA and auxiliary equipment for the
smooth operation of the manufacturing process. The plant utility department and
the plant as a whole were the major beneficiaries of my project resulting in
zero occasions of power interruption and deviation of manufacturing operations
due to this issue.
C.E.1.4.3 My achievements on the project
It has taught me
to manage the various crisis and challenging situations. It has helped me to imbibe
knowledge about the technical and safety standards related to the project. It
has aided in ameliorating my courage and determination which has, in turn, helped
me to successfully accomplish the task meeting each and every requirement of