lab 1 introduction of elecrical machines

POLITEKNIK SULTAN ABDUL HALIM

MU’ADZAM SHAH

LABWORK 1

JABATAN KEJURUTERAAN ELEKTRIK

LABORATORY MANUAL

GROUP CLASS SESSION LECTURER FAIRUZ ABADI BIN KHALID

NAME REGISTRATION NO

Prepared By Revised and Signed by

(FAIRUZ ABADI BIN KHALID) (Head of Department / Head of Programme/ Curriculum Officer)

Date: Date:

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ET301 : Electrical Machines


MU’ADZAM SHAH

LAB -1

Title : Introduction Of Electrical Machine

Objective :

At the end of this experiment, the student should be able to :1. State the type of D.C and A.C Machine.2. Identify the main part of the D.C and A.C machine.3. State the function every parts of the D.C and A.C machine. 4. Know the different between D.C and A.C machine.

Equipment:

1. D.C machine: Series D.C , Shunt and Compound Machine.2. A.C machine Squrrial Case Motor and Slip Ring Machine.

Theory:

Machines that convert mechanical energy to and from electric energy.- Motor convert electrical energy into mechanical energy.- Generator convert mechanical energy into electrical energy.

Motor can be divided into :

AC Motors – powered by AC sources which can either be single phase or three phase. - most common type is induction motor and synchronous motor.

DC Motors – powered by DC sources.

Basic components of the machine:

1. Stator – stationary part.2. Rotor – rotating part.3. Shaft – coupled the machine to the mechanical load.

In most types of machines, a given windings can be classified as field winding or as armature winding.Field winding - to set up the magnetic field required to produce torque.Armature windings - carry currents that vary with mechanical load. When the machine is used as a generator, the output is taken from the armature windings.

Machine nameplate :

The National Electrical Manufacturer's Association (NEMA) specifies that every motor nameplate must show these specific items: Manufacturer's Name; Rated volts and full load amps; Rated frequency & number of phases; Rated full load speed; Rated temperature rise or the insulation system class; Time rating; Rated horsepower; Locked rotor indicating code letter; Service Factor; Efficiency; Frame Size; and Design Code. Additional information will normally appear on most nameplates.

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Direct current or DC electric motors work for situations where speed needs to be controlled. DC motors have a stable and continuous current. DC motors were the first and earliest motors used. They were found, however, to not be as good at producing power over long lengths. Electric companies found using DC motors to generate electric did not work because the power was lost as the electric was transmitted. Brush DC motors use rings that conduct the current and form the magnetic drive that powers the rotor. Brushless DC motors use a switch to produce the magnetic drive that powers the rotor. Direct current motors are often found in appliances around the home.

Alternating current or AC electric motors are used differently based on what type of AC motor it is. Single phase AC motors are known as general purpose motors. They work well in many different situations. These AC motors work great for systems that are hard to start because they need a lot of power up front. Three phase, also called polyphase, AC motors are usually found in industrial settings. These motors also have high starting power built transmit lower levels of overall power. AC power gets its name from the fact that it alternates in power. The amount of power given off by an AC motor is determined by the amount of power needed to operate the system.

DC and AC electric motors are found everywhere from the home to the car to industrial plants. Motors are important to everyday life. Dc motors were introduced and caused a great revolution in the way many things are done. When AC motors came on the market the way motors were looked at changed because of their amazing starting power potential.

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Procedure:

1. Get all the equipment mentioned above.

2. Identify the parts of D.C electrical machines.

a. Make observations of the direct current machine sections found in the laboratory in accordance with section diagram below.

3. Identify the type of direct current machines.4. Draw and label the terminal connection of machines that have been identified in the columns below.

Series Machine Name plate

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Shunt Machine Name plate

Compound Machine Name plate

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5. Functions of the important parts of a direct current machine.5a. Amature.

_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________

b. Field Pole

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c. Comutator_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________

d. Carbon Brush_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________

e. Yok / Frame

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6. Draw a pattern of self-excitation generator circuit connections.

a. Series Excitation

a. Shunt Excitation

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b. Shot Compound Excitation

a. Long Compound Excitation

7. Identify the parts of A.C electrical machines.

8. Make observations on the current machine alternating section found in the laboratory according sectional diagram below.

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9. Identify the types of alternating current machines.

10. Draw and label the terminal connection of machines that have been identified in the columns below.

Squirrel Cage Machine Name plate

Slip Ring Machine Name plate

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11. Draw a pattern of Three Phase motor circuit connections.

a. Star

b. Delta

12. The main part of function a alternating current machine.a. Rotor

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

b. Stator

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a. Slip Ring

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13. Discussion:

a. State the difference between direct current machine (D.C) and alternating current machine (A.C).

b. Draw and explain the right hand Fleming’s rule.

14. Conclusion

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lab 1 introduction of elecrical machines

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