|Btec HNC in Construction and the Built Environment
Assignment Front Sheet
|Program No.||MM 758||Qualification:||Building Services Engineering|
|Unit Number:||50||Unit Title:||Electrical Installation for B.S.E|
|Learner Name:||Registration No.|
|Assignment Title:||Understand DC and AC motors||Assignment No:||3 of 4|
|Hand in dates & times.||First Draft:||in stages|
|Final submission:||See Turnitin dates.|
|Copied work will be graded as a FAIL and disciplinary action may be taken against you
I certify that the work submitted for this assignment is my own
|Learner’s signature:||Date:||/ /|
|Assessor’s comment on final submission|
Assignment approved for use in academic year 20010/11
|Learner feedback on this assignment|
|If you have any comments for your assessor about this assignment – please use this space
The criteria below are available in this assignment. Assessor initials in this grid indicate which criteria have been awarded
Assignment writer to edit grid to match criteria covered in this assignment
|Assessor Name:||R Pareccini||Date|
|Internal Verifier:||Date IV’d:|
|Date of Issue:||16 /09 / 2014||Submission is:||Moodle – Turnitin|
|Unit No.||50||Unit title||Electrical Installation for B.S.E|
|Grading Criteria||Page No||Achieve
Actions you must take to meet assignment criteria
|PASS grade criteria|
|Examine DC series and shunt motor applications|
|Explain how to control the speed of DC series motors using thyristor control|
|LO 3.3||Calculate the theoretical ratings of motors for a given duty|
|LO 3.4||Explain starting methods and speed control for AC motors.|
|LO 3.5||Evaluate the suitability of AC motors for building services applications|
|DISTINCTION grade criteria É Learner to enter Page Numbers before submission|
|Take responsibility for managing and organising activities|
|Assignment Number||3of 4||Assignment title||Understand DC and AC motors|
As a newly appointed Electrical Engineer for a large Electrical Contractor, you are part of the project team involved in the feasibility and provisional electrical design for a new leisure centre block (see attached drawings).
You have been asked to produce a portfolio of evidence that includes the provision of electrical machines (DC and AC) and associated control equipment.
Examine DC series and shunt motor applications
| Task 13
DC motors are ideal for a wide range of applications, including:
Ski lifts – Printing presses- Heavy Moveable Structures – Paper Milling- Cranes – Iron, Steel and glasswork-
You need to include manufacture data for the chosen motor.
Explain how to control the speed of DC series motors using thyristor control
| Task 14
With the aid of a diagram explain how to control the speed
of a DC series motor using thyristor control.
(You may use the multisim software to construct the circuit).
Calculate the theoretical ratings of motors for a given duty
A servomotor for plastic moulding machine
has a repetitive duty cycle as follow:
Time (s) 10-15 15-25 25-35 35-50 50-55 55-60
KW Load 1 2 1 3 1 4
With the aid of a diagram,
depict the duty cycle above
(x axis = time in seconds, and y axis = power in Kw).
Determine the minimum motor rating.
Explain starting methods and speed control for AC motors.
The selection of a suitable starting method for a motor/load combination is becoming increasingly important.
Explain how the different types of motor starters works ( D.O.L – Star / Delta – Rotor resistance – soft start, VFD). Use diagrams to support your answers.
Also explore how you can control the speed of a Three phase A.C. motor using solid state devices.
Evaluate the suitability of AC motors for building services applications
The Building Regulation approved documents F and L have signalled a big shift toward energy-efficiency buildings. Refer to UK regulations only.
Select and justify an appropriate AC motor for the following applications:
Employer Engagement and Vocational Contexts
Support to enable centres to initiate and establish links to industry and to networks arranging visits to industry and from property practitioners is given below:
Indicative reading for learners
Technical Index – B.S. (from Moodle – On line resources).
BS 7671:2008 (AM1)
Electrical circuit theory & technology (John Bird)
Building Regulations Approved documents. (Planning portal.gov.uk)
Building Services Handbook ( Fred Hall & Roger Greeno)
ABB/Schneider technical books.
Wiring matters- CIBSE Guides.
The student is expected to research further using the internet (ensure you quote all references)
Where there is evidence of plagiarism the assignment will be rejected and the candidate will have to re-submit the work. This will jeopardize your chances of completing the unit.
Work that is not handed in on time will not be graded.
You may hand in completed tasks at different times to those shown, but work must be handed in to gauge the progress being made.
You must hand in the Marking Grid each time you hand in work for assessment.
The assignment will not be assessed unless accompanied by the marking grid.