MOTORS AND GENERATORS

Transcription

1 MOTORS AND GENERATORS KICKSTART PHYSICS WORKSHOP LIST OF EXPERIMENTS 1. The Motor Effect 2. Electromagnetic Induction and Lenz s Law 3. Generators 4. Transformers 5. AC Induction Motors Name: Kickstart would like to acknowledge and pay respect to the traditional owners of the land the Gadigal people of the Eora Nation. It is upon their ancestral lands that the University of Sydney is built. As we share our own knowledge, teaching, learning, and research practices within this University may we also pay respect to the knowledge embedded forever within the Aboriginal Custodianship of Country.

2 Generate some motor-vation Write an interesting fact you learnt about Physics List three risks in the 2 nd year lab Risk Consequence Precaution Find and list the 4 famous scientists in the lab. Careers with Your demonstrator might be able to help with this. What sort of career do you think you could get if you studied this topic at the University of Sydney? Industry Research Public service

3 The University of Sydney The Motor Effect An electric charge experiences a force when it moves in a magnetic field. Thus, a current-carrying conductor feels a force from a magnetic field. This is the motor effect. Label the parts of the motor on the pictures below. Are these DC motors or AC? Or both? How can you tell? Rotor Stator Power source Brushes Communtator Describe the application of the motor effect in the galvanometer and the loudspeaker Galvanometer Loudspeaker Features: Features: Characteristics: Characteristics:

4 Electromagnetic Induction and Lenz s Law Lenz s Law There are 4 parts to Lenz s Law. A changing flux induces an force that gives rise to a that the original change in magnetic flux. Magnet and coil Predict Observe Apply Falling magnet Jumping rings Pendulum Arago s disk

5 Generators AC/DC Generator How can you tell if the generator is producing AC or DC electricity? Draw the output of the generator as viewed on the CRO screen for both AC and DC Predicted Observed Twelve-phase generator Predict and draw what you think the output of the generator would look like on the CRO: Predicted Observed

6 Transformers Transformers use the ideas of electromagnetic induction to transform one voltage into another. We can use experimentation to determine the relationship between the voltage and the number of turns in the coil. First we can count the number of turns in the coil, then use the multimetre to measure the voltage. Record your results in the table, then graph the data. Volts, V s (V) Number of coils, N s Title

7 Conclusion: From this graph, what can you say about the relationship between the voltage and number of turns in the secondary coil? How would you represent this mathematically? Hint, it s a straight line. Discussion: You have the relationship between the secondary voltage and coils, Calculate the relationship between the primary voltage and coils? V! n! = Are they the same? Can you write a general expression for all of these 4 terms? In Physics, we look for the relationship between things and a graph is one of the best ways of doing this, especially if the graph gives us a formula that we can understand, like a straight line. Once we have an expression for the graphical information, we can manipulate that expression to find more theories and applications for example.

8 AC Induction Motors Constuct from the parts provided, a working AC induction motor. Complete the table below for each type of motor. Description Component DC motor Universal Motor AC Induction motor Rotor Stator Commutator Power supply Physics concept behind motor Applications/ Examples

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