UNIVERSITY OF MINES AND TECHNOLOGY
ELECTRICAL AND ELECTRONIC
ENGINEERING DEPARTMENT
25 June 2020
Electric Haulage Machinery
EL 472
ASSIGNMENT 3
Name: __Abdul Fatawu Kamal Deen___
Index No: _42200116__________
1.
Item
Lecture 5 Presentation
Lecture 6 Presentation
a. How many short videos 4
were shown
4
b. List topics discussed in 1. Types of Locomotives
each video
2. Types of braking
1. HVDC and HVAC
systems. Also, the
2. Electrical substation
various items required
3. Substation
for braking of motors.
(maintenance basis)
3. Electrical braking
safety
4. Transmission line and
electric grid system
methods.
4.
transmission
Train brakes theory.
c. After which slide numbers 1 - slide 9
were the videos shown
2 - slide 21
1 - slide 6
2 - slide 10
3 - slide 21
3 - slide 17
4 - slide 26
4 - slide 26
2.
1. Steam locomotives
2. Diesel locomotives
3. Electric locomotives
1
3.
Regenerative braking is employed when the current produced during braking is fed back into
the power supply system for use by other traction units, instead of been wasted as heat
whereas in Rheostatic braking the electrical energy produced by the motors is dissipated as
heat by a bank of onboard resistors. Also large cooling fans are required to prevent overheat
thereby preventing damage of the resistors.
4.
HVAC
HVDC
Transmission of 50Hz frequency cannot be It does not have any frequency, therefore it
interconnected with transmission of 60 Hz is easy to interconnect two different DC
frequency, hence asynchronous connection transmission circuits
is not possible
Voltage drop is high
Voltage drop is low
It transmit AC current
It transmit DC current
Presence of skin effect
Absence of skin effect
Occurrence of corona losses
Absence of corona losses
5.
Main Elements
Functions
Transformer
It transforms voltage from one level to
another level under the same frequency
Circuit breakers / Fuse
It interrupts the flow of current after
detecting a fault by isolating the faulty
equipment
Earthen mesh
It provides grounding connection to
substation equipment and non-current
carrying objects, to discharge charges
between phase and ground by means of
earthen switches and to ensure safety against
electrical shocks
2
Lightening arrestors
They prevent the flow of normal power to
ground, but provide a path over which high
voltage current flows, bypassing the
connected equipment
Wave trap
They separate
high frequency
communication signals from normal power
frequency
6.
Hazards
1. Electrical hazard
2. Liquid or gas hazard
Safety Precautions
1. Regulation inspection
2. Proper use of ladder
3. Lifting things appropriately
4. Alerting people around on possible hazards
3
3. Personal hazards