Power Systems Lab 1

ELECTRICAL & COMPUTER ENGINEERING

EEL 4213L

POWER SYSTEMS LAB

TRANSFORMERS AND MACHINES

Experiment 1

Transformer Voltage, Current and Impedance Ratios

Lab Instructor:

Group Members:

09/01/2011

TRANSFORMERS AND MACHINES

Experiment 1

Transformer Voltage, Current and Impedance Ratios

Purpose:

In this lab we studied the relationship between voltage and current in a transformer.

Equipment:

1. One Hampden Transformer (Model T-100-3A)

2. One Hampden RLC-100 [Resistance-Reactance Load]

3. One Hampden Resistance Load

4. Two Hampden AC ammeters

5. One Hampden AC voltmeter

6. One Hampden 120 volt fixed AC power supply

7. One portable [AC voltmeter (rated at least 75 volts]

8. One portable [AC ammeter (rated at least 1 amp)]

Background

Transformers transform electrical energy according to the laws of conservation of energy..

Electrical laws consider the following two laws: According to the law of conservation of energy, the power delivered by a transformer cannot exceed the power fed into it. The power dissipated in a load at any instant is equal to the product of the voltage across it and the current passing through it. It follows from the above two laws that a transformer is not an amplifier. If the transformer is used to change power from one voltage to another, the magnitudes of the currents in the two windings must also be different, in inverse ratio to the voltages. Thus if current were to be brought down by the transformer, voltage would go up. If voltage were to be brought down by the transformer, current would go up.

A current flowing through a coil (primary winding) produces a magnetic field (flux). If the current alternates (AC) so will the magnetic field (Flux). If another coil (secondary winding) is placed near the primary winding the varying magnetic field will induce a voltage in the secondary coil.

Two coils that have mutual inductance make up a transformer. The coil connected to the...