Group lab report Electromagnetic induction and transformers

docx

School

Miami Dade College, Miami *

*We aren’t endorsed by this school

Course

131

Subject

Physics

Date

Jan 9, 2024

Type

docx

Pages

Uploaded by MateKoupreyPerson718

PHYSICS LABORATORY LAB REPORT – 60% OF THE LAB GRADE (Complete and save in pdf, send it by assignment in blackboard) Name (Last, First) Zahan, Ilma Segura Alvarez, Fabiola Zchesan, Leonel Title of the lab: ELECTROMAGNTETIC INDUCTION AND TRANSFORMERS. Date 06/30/2022 OBJECTIVES: (5 points) 1) Verify the Faraday-Lenz‘s Law 2) Perform measurements with a set of coils to understand how a transformer works. MATERIALS: (Complete by watching the video to the measures ) . • Galvanometer • Set of coils • Iron core • Magnets • Power supply (marked as Faraday)  Multimeter EXPERIMENTAL PROCEDURE: ( 5 points) The experiment consisted of introduce a magnet inside a coil setup to a Galvanometer. First, the professor introduced a North Magnet inside the coil, once it was inside, the Galvanometer started to read a flow current. Second, the professor removed the North Magnet and the Current changed direction to right. Third, the professor introduced a South Magnet and executed the same process to introduce and remove the magnet inside the coil. The Galvanometer read the current but, in this case, the current flowed from left to right. Change of the movement causes the current. Change in magnetic field, when it sees the coil, it responds. Red north pole, white south pole. Change of the magnetic field inside the coil, you get the current change. Change in the magnetic field. Write the equation of the magnetic flux and the name of each term (5 Points) ∅ B = B Scosθ ∅ B is the magnetic Flux B is the magnetic field intensity.

S is the area. ϴ is the angle between the vector B and normal vector to S. Area is perpendicular to the coil Write the Faraday´s law equation and the name of each term. (5 points) ∈ = − d ∅ dt where ∈ is the electromotive force (EMF) and ∅ B is the magnetic flux . EXPERIMENTAL RESULTS: DATA, CALCULATIONS, TABLES, GRAPHS PART I: Electromagnetic Induction. Watch the video. RESULT ANALYSIS 1. Describe what happened when the magnet was moved toward the coil slowly and quickly .(10 points) When the coil is moved slowly, the current goes to 0 and when it is moved quickly it goes back and forth in the current measurement. There is a direct relationship between the North and South magnet and the coil’s movement. When each magnet was moving slowly it was creating a slow current meanwhile a quick magnet’s movement created more current. 2. Why is there absence of induced electric current when the magnet remains at rest inside the coil?. .(10 points) When the magnet is at rest inside the coil, the magnetic field and flux is constant and there is no inductive voltage. There is absence of induced electric current because the magnetic flux becomes constant, hence, the induced electric current becomes zero because the derivative of a constant = 0. In previous question we described the direct relationship between the coil movement and the magnet because it based on Faraday’s Law. Again, in this question if the magnet remains at rest, it is not producing a change in the magnetic field therefore there is not an induced current in the coil.

PART II: Transformers. The experiment consisted of putting transformers connected to a primary and secondary coil onto an adjusted platform. Once they were setup in the platform the AC power generator was connected to the set of transformers and the multimeter was also connected to the coils. After everything was connected the students proceed to manipulate the current coming from the AC generator. These changes produced different coil’ lectures in the multimeter. Once all the lectures were showing in the multimeter, the students took notes on how the primary and the secondary coil changed every time there was a change of current and made a final calculations in the below tables. A transformer consists of two coils, primary and secondary coils, mounted onto an iron core. When the switch in the primary circuit is closed, the ammeter in the secondary circuit deflects momentarily. The EMF (electromotive force) in the secondary circuit is caused by the changing magnetic field through the secondary coil. TRANSFORMER A. Set two coils (Primary 200 turns and Secondary 400 turns) on to the iron core. Connect the first to the multimeter and the second to a AC power supply . (10 points) Primary voltage Secondary Voltage V s V p Primary Turns N p Secondary Turns N s N s N p 1.03 1.74 1.689 200 400 2 2.01 3.48 1.731 200 400 2 3.04 5.30 1.743 200 400 2 4.04 7.24 1.792 200 400 2 5.01 9.03 1.802 200 400 2

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

TRANSFORMER B . Set two coils (Primary 1600 and Secondary 800 turns) onto the iron core. Connect the first to the multimeter and the second to a AC power supply. (10 points) Primary voltage Secondary Voltage V s V p Primary Turns N p Secondary Turns N s N s N p 1.01 0.41 0.4059 1600 800 0.5 2 0.82 0.41 1600 800 0.5 3.02 1.25 0.4139 1600 800 0.5 4.01 1.67 0.4165 1600 800 0.5 5.01 2.10 0.4192 1600 800 0.5 RESULTS ANALYSIS 1. Why we should use an AC power supply and not a CD power supply for the transformer? . (10 points) Because the AC power supply gives the voltages according to the time, so it is changing with respect to time. We should use an AC because to be able to obtain an induced voltage, the magnetic field should change with time so that when the primary current changes so does the magnetic flux and magnetic field. If DC is used, the magnetic flux and field is constant and if it is constant, there is no voltage. If we want to get induced current, we must create a change in the magnetic field over the time elapsed. In the Alternative current the magnetic field changes over time while in the Direct Current the magnetic field remains constant and if the magnetic field stays constant over time there is not a change of voltage. Here it showed a proportional relationship betweem the magnetic field and current in primary coil, when the first changed the second did as well. 2. Find, with your measurements, the transformer equation; Vs/Vp =Ns/ Np (this transformer equation tells how the output voltage is related to the input voltage. .(10 points) Ideal transformer equation. The below formula shows the “Ideal transformer equation”. Vs / Vp = Ns / Np Vs = (Ns / Np) * Vp This calculation is not only the ideal transformer equation. Also, it shows that Vs/ Vp is equal

to the slope because the Ns/Np is the turns ratio. 3. If the secondary coil contains more loops than the primary coil ( Ns > Np) we have a step-up transformer, but if ( Ns < Np) we have a step– down transformer. According to your measurements when we have a step-up or a step-down transformer? .(10 points) Step up transformer- voltage increased in the secondary. According to the measurement, transformer a is step up and B is step down. Based on data from transformers above, the Transformer A was a step-up while Transformer B was a step-down. 4. Explain why does the secondary voltage increase when you increase the primary voltage? (10 points) The voltage on the secondary is directly proportional to the primary. The directly relationship between these two is due to induction. A higher voltage in the primary creates a higher current hence the induced voltage in the secondary increases. Vs/Vp = Ns/Np Vs = Ns/Np * Vp The voltage in the secondary is directly proportional to the voltage in the primary. CONCLUSIONS: Critical analysis about the fulfillment of each objective (8 points). Two separate paragraphs, one by each objective (comment the errors) (2 points). 1) The objective to verify the Faraday & Lenz’s Law was executed. In the first experiment the students were able to proof that any change in the magnetic field will cause a voltage to be induced in the coil thus whenever the magnet was introduced in the coil the Galvanometer showed a change in current. Also, in the first experiment was proved the Lenz’s law which means the induced electric current flows in a direction such that the current opposes the change that induced it. For example, when the North Magnet was introduced the Galvanometer read the current was flowing to the right and moved to left when North Magnet was removed. Same process happened with South Magnet but in this case once South Magnet was introduced the Galvanometer read first to left and later to right once the magnet was removed. 2) The objective to understand how transformers work were completed. The students were capable to proof that the Alternative Current is the only one suitable to work with

transformers when the goal is to create induced electromagnetic field. The Direct Current would not be a good source to be applied in a transformer electric system because the constant of magnetic field would not create the goal of induced current. Also, the student understood the direct relationship between the primary and secondary voltage. Once the first one increased the second increased as well due to induction. 3) Some of the errors in this experiment are the measurement of the voltage, human error. In the lab we have a real transformer and not an ideal one. Maybe due this, the real transformer is missing voltage. Another error could be the heat which causes to lose a bit of voltage, hence the discrepancy in the measurements and lab.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Group lab report Electromagnetic induction and transformers

Related Documents