Transformer Wiring Lab Group Activity

Transformer wiring Lab Group Activity

Worth:

27 points

Pages of Information:

Ch 20 p.586-595 Grob 9th ed.

Equipment:

Multimeter

120 vac to 13.8 vac transformer single tap output

multiple output / multiple secondary output transformer

Directions:

On page 592 there is a picture of a 12v transformer with a diagram of its wiring. Using the transformers provided measure the primary side, black wires and note its resistance value. Then on the secondary side measure the resistances of the 2 secondary taps.

Draw schematic here from p. 592 include the Resistance Values on the schematic: (5 pts)

Is this transformer a step up or step down transformer. (2 pts)

What does the dots on the schematic represent? (2 pts)

What is the ratio between the number of turns on the primary to the secondary of this transformer? (3 pts)

Create a table similar to the example that is provided at the end of this activity sheet. Sometimes we may not know what the outputs are for a transformer there is a simple way to determine the outputs of it by measuring the resistance of all combinations of the primary and secondary side of the transformer. First, remove the transformer and there is no load to it. It must be removed in order for this to work. Second, you need to set up a graph to make sure you have measure the resistance between all wire combinations on the primary side and then do the exact same thing and measure the secondary side. The resistance values that you measure will “paint a picture” of what wires are tapped together or not.

For example look at example given, notice how the graph is set up. We need to check all inputs and outputs of wire combos. On the primary side the black wire is the tapped to the two black with yellow wires. So there is a black wire central tapped with the black and yellow wires are the outer wires, most likely this to have either a 120 volts hooked up to the black and then the other lead to the black and yellow wire. Or it could have 220 hooked up to it with both black and yellow wires. There also is a red center tap that is the central tapped to the outer red/yellow wires. Again this could be used for 2 different voltages or for a second output on the secondary side.

Using EXCEL construct a spreadsheet similar to the example provided and measure a transformer of your choice. Submit it at the back of this handout. (10 pts)

Using the various examples on p.592-594 make a diagram as best you can deduce about the way this transformer is wired. (5 pts)