Hi! Today I’m going to do a tutorial on How to check for the Voltage Output of Multi – Tap Single Phase Step down Transformer. These tutorial was based on my personal knowledge, experience and ideas.

Definitions:

Power Transformer

• A Power transformer is an electrical device that is use to change voltages and currents of AC electric power. The basic principle of these device was based on the statically induced emf.

Classification of power transformer

1. Single phase step down/step up power transformer with single output.
2. Single phase step down/step up power transformer with multi tap.
3. Three phase step down/step up power transformer
   For these tutorial we will focus purely on Single phase step down/step up power transformer with multi tap. It is a type of transformer that has a multiple output with only one input. For instance, input of 230 with an output of either 4.5, 6, 9 or 12 volts AC.

Why we need to check the output of the power transformer?

• Output of the transformer must be identified before using it to any form of electrical application. Because, voltage is a very important parameters in electrical circuitry.

Friendly Reminder: always consider safety in handling electricity. I suggest to use electrical gloves or any applicable safety equipment in performing the experiment/job.

Materials Needed:

1. Power Transformer
2. Circuit Breaker
3. Digital Tester
   See attached photo below
   
   Own photo

Below are the Procedures:

P1: Connect the input terminals of the power transformer to the load side of the circuit breaker. The circuit breaker will act as a switch and the same time as a protective device for unwanted events to occur (Note: Use smaller value of circuit breaker ex. 15 A below). Then connect the source side of the circuit breaker to the available power outlet.
See attached photo below

Own photo

P2: Turn on the circuit breaker and measure the voltage at the input terminal using digital tester. It is done to know if the power transformer is being supplied/energized by the source. The desired reading is 230 V as a nominal voltage of the Philippines. Nominal voltages may differ for other countries please be guided.
See attached photo below

Own photo

P3: Measure the voltage on the output terminal of the power transformer using the digital tester. Connect the black test probes on the common terminal commonly labeled as ZERO and the red test probes to the other.
See attached photo below

Own photo
It implies that at this terminals of the power transformer the voltage rating is 4.86 V.

P4: Measure the voltage on the output terminal of the power transformer using the digital tester. Connect the black test probes on the common terminal commonly labeled as ZERO and the red test probes to the other.
See attached photo below

Own photo
It implies that at this terminals of the power transformer the voltage rating 5.70 V.

P5: Measure the voltage on the output terminal of the power transformer using the digital tester. Connect the black test probes on the common terminal commonly labeled as ZERO and the red test probes to the other.
See attached photo below

Own photo

It implies that at this terminals of the power transformer the voltage rating 9.38 V.

P6: Measure the voltage on the output terminal of the power transformer using the digital tester. Connect the black test probes on the common terminal commonly labeled as ZERO and the red test probes to the other.
See attached photo below

Own photo
It implies that at this terminals of the power transformer the voltage rating 12.75 V.

Generally, the transformer has 220 V as an input and 4.86, 5.70, 9.38 and 12.75 Volts.

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