CONSTRUCTION OF ELECTRIC MOTOR FROM THE KIT - PowerPoint Presentation

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CONSTRUCTION OF ELECTRIC MOTOR FROM THE KIT

VCE Physics, Unit 4;Area of Study – ELECTRIC POWER gracie.saxena@manorlakesp12.vic.edu.auJoshua.le@manorlakesp12.vic.edu.au

joshua.le@manorlakesp12.vic.edu.au

joshua.le@manorlakesp12.vic.edu.au

joshua.le@manorlakesp12.vic.edu.au

joshua.le@manorlakesp12.vic.edu.au

Aim

To build a working model of Electric Motor and develop understanding regarding:Various components of a simple DC motorThe operation of a simple DC motor, including the role of the commutator (slip rings)

Magnetic force experienced by a conductor and a non-conductor when placed in magnetic fieldInteraction between the magnetic field of the magnet and the magnetic field generated around a conductor carrying current(or we can call it electromagnet)- Main principle used for Electric Motors

Dissecting a small DC motor

The Hudson Motor Kit

Equipment: A power pack

A small non- conductor rod (I used plastic and wooden tooth picks)A pair of scissors to cut the wires.The Motor Kit, which has following components.A pair of bar magnets whose poles are on the longer side (not on the either ends of the bar)A metallic rod to be used as shaftA plastic cylinder for armature windingTwo roles of insulated copper wire to be used as stator coilsCarbon brushesA few more components to hold the above parts togetherhttps://www.youtube.com/watch?v=m95DAhh5Ack&feature=youtu.be

Procedure:

Check the polarity of magnets and place the opposite poles facing each other to generate magnetic field between themExperience magnetic force on the metallic rod (that came in the kit) and compare magnetic force on non-conducting material

Fix the plastic cylinder for armature windingWind the insulated copper wire around the cylinder leaving long ends to be attached with slip ringsPut all the components together as shown in the diagram (given on the instruction manual provided with the kit)Finally connect the brushes with the power pack. We can see the simple DC motor working when power is turned on.The Hudson Motor Kit

Changing the variables:

The turning effect on the coil can be increased by:Increasing the currentUsing a stronger magnetIncreasing the number of turns on the coilIncreasing the area of the coil. (A longer coil means higher forces because there is a greater length of wire in the magnetic field; a wider coil gives the forces more leverage.)

The Hudson Motor Kit

How students can use DC Motors for their EPI

Students may construct a working model of a DC motor and measure its efficiency by comparing the correlation between the voltage and the load placed on the motor.

My students used the following equipment:The ‘Hodson’ DC motor kit Power supplyThread to hang loadLoad (paper clips)

Concepts Covered:

Magnetic force experienced by a magnetic and a non- magnetic material when placed in a magnetic field.Magnetic effect of a current- Right hand grip rule

.Magnetic fields from coils(Electromagnets)Magnetic force on a current- Right hand palm rule.

How DC motor works.

As current flows through a coil inside a magnetic field, one side that is perpendicular to the magnetic field experiences an upward force, while the opposite side experiences a downward force of equal magnitude, due to the current flowing in opposite directions. The combination of forces on the coil causes torque to make it rotate. The direction of the current needs to be reversed so that the coil continues rotating in the same direction, and this is achieved by a split-ring commutator, which changes the direction of current flow twice every rotation.