Inductance

Transformer Applications

Investigate the many applications for transformers on the internet and in your textbook. After noting several applications, choose one application and explain it in detail. Also, include a discussion of how transformers may be used to improve the safety of devices connected to high voltage AC systems.

Assignment

1. Calculate the inductance of a coil that induces 120V when the current through it changes at a rate of 5A/s.

2. Calculate the inductance of a coil that induces 850V when the current through it changes at a rate of 30mA in 2µs.

3. Given an iron core with 200 turns, a length of 0.35m and an area of 3x10-4m2, determine the inductance.

4. A 10:1 transformer has NP = 300, VP = 240V and IP = 2A.Determine NS, VS, and Is.

5. Four inductors of values 6mH, 7mH, 9mH, and 10mH are connected in series.Determine the total inductance.

6. Four inductors of values 6mH, 7mH, 9mH, and 10mH are connected in parallel.Determine the total equivalent inductance.

7. Calculate the energy store in a 20mH inductor with a current of 3mA flowing through it.

Submit all calculations in a document entitled EE115W4AYourGID.docx, or an equivalent word processing file extension

LAB

Transformers

1. Watch the videos

. Week 4 Video Lecture – Multisim Transformers

· Consider the circuit demonstrated in this week’s presentations. With the turns ratio modified to 20:1, calculate the following values of Vs and Is for the given values of RLin the table below:

· Construct the transformer circuit in MultiSIM and complete the table in part 2 with the measured values of Vs and Is for each value of RL. Use the Agilent Digital Multi-meter to take the measurements and capture a screen shot of each measurement.

· Discuss the following:

Describe the relationship of RL on the secondary voltage.

Describe the relationship of RL on the secondary current.

How do the calculated values compare to the measured values?

How would you go about calculating the transformer power efficiency?

How would you go about measuring the transformer power efficiency?

Determine the transformer power efficiency for the circuit in MultiSIM. Include a calculation and a measured value.

Include all calculations, screenshots of measurements, the table results of part 2 and the answers to part 4 in a word processing document and submit as EE115W4LabYourGID.docx, or an equivalent word processing file extension.

MIDTERM

Show work for full credit. Include MultiSIM screenshots where indicated.

1. For the circuit below, solve for the following:

1. RT

2. IT (pk), IT (p-p), IT (rms), IT (avg)

3. Voltage drops across all individual resistors

a. VR1 (pk), VR1 (p-p), VR1 (rms), VR1 (avg)

b. VR2 (pk), VR2 (p-p), VR2 (rms), VR2 (avg)

c. VR3 (pk), VR3 (p-p), VR3(rms), VR3 (avg)

d. Period of the source VT

e. Capture screen-shot of VR1 (p-p), VR2 (p-p), VR2 (p-p). Use Tektronix Oscilloscope in MultiSIM.

2. For a fixed frequency of f= 500Hz and the values of C below, determine XC:

b. C = 1.0uF Xc = ?

b. C = 0.5uF Xc = ?

b. C = 0.2uF Xc = ?

b. C = 0.1uF Xc = ?

1. Determine the following:

c. XcT for two capacitors in series with the values Xc1 = 200ohms and Xc2 = 800ohms

c. XcEQ for three capacitors in parallel with the values Xc1 = 200ohms, Xc2 = 800ohms and Xc3 = 1000ohms

1. For the circuits below, determine CEQ and CT respectively:

1. For the circuit below, determine the following (express all answers in phasor form). No work equals no points. Include screenshot from MultiSIM for Single Frequency AC Analysis to confirm your calculations.

. XC

. ZT

. IT

. VR1

. VC1

· Given an iron core with 500 turns, a length of 0.50m and an area of 2x10-4m2, determine the inductance.

· A 20:1 transformer has NP = 200, VP = 220V and IP = 4A. Determine NS, VS, and Is.

· Four inductors of values 5mH, 9mH, 15mH, and 17mH are connected in series. Determine the total inductance.

· Four inductors of values 5mH, 9mH, 15mH, and 17mH are connected in parallel. Determine the total equivalent inductance.

· Calculate the energy store in a 15mH inductor with a current of 5mA flowing through it.

Submit your work in a document entitled EE115MidtermYourGID.docx, or an equivalent word processing file extension.