Ateneo de Naga UniversityCollege of Engineering

ECE and CpE DepartmentS/Y 2014-2015

Group Members:Joa Allen See

Timothy Paul PronJohn Kristoffer Villareal

GE41

Date Performed: June 19, 2014Date Submitted: June 26, 2014

EXPERIMENT NO. FAMILIARISATION

OBJECTIVES:

To be able to understand the theories and concepts of a transformer and its operation. To be able to understand how a transformer works without a load. To be able to understand how a transformer works with a load.

PRACTICAL 1.1 – FAMILIARISATION TEST

Procedures:

1) Take the Dissectible Transformer apart as described in Chapter 1.

2) Remove the large coil and reassemble the transformer with just two smaller coils in

position.

3) Assemble the equipment into the frame as shown in fig 4.1.3 Make all connections

shown, including connections d to g of the transformer.

4) Ensure that the dial on the Variable ac/dc Supply 60-121 is set to the zero position and

that the output switch is in the ac position.

5) Switch on the Earth Leakage Breaker 60-142, if connected.

6) Switch on the 60-121 by pressing the green power on/off button and raise the set voltage

to 5V using the ‘output voltage’ dial. This is the voltage applied to the primary and is

read on the left hand voltmeter.

7) Now read the voltage induced in the secondary coil displayed on the right hand

voltmeter. This should also read approximately 5V.

8) Switch off the 60-121 by pressing the green power on/off button.

9) Remove the coils from the core but keep them together.

10) Switch on the 60-121, and reset the primary voltage (left hand voltmeter) to read 5V.

Read the secondary voltage value (right hand voltmeter). The voltage will have fallen to a

very low level, hardly readable.

11) Place the “I” lamination through the center of the two coils and observe a small increase

in secondary voltage.

12) Separate the two coils and observe that the secondary voltage becomes negligibly small.

13) Switch off the 60-121 by pressing the green power on/off button when there tests are

completed.

Results:

Primary Voltage Secondary Voltage

At transformer core 5.11V 4.52V

No core 5.15V 264mV

With I core 5.15V 1.135V

Separated coils 5.15V 6mV

PRACTICAL 1.2-VOLTAGE RATIOS ON NO LOAD

Procedures:

1) Make the connections on the mimic panel as shown in fig 4.1.4. Assemble the

transformer according to the instructions in Chapter 1. Connect the Dissectible

Transformer leads into the sockets a to g on the front panel ensuring that the identifying

letters on the leads and sockets correspond.

2) Switch on the 60-121, set the primary voltage to 20V (read on the left hand voltmeter).

3) Record the voltage read on the secondary voltmeter (right hand side) in Table 4.1.1

(secondary connection de).

4) Switch off the 60-121.

5) Repeat the experiment for the other connections listed in Table 4.1.1 and record the

results.

6) Switch off the 60-121.

Results:

Voltmeter 1 Voltmeter 2 Voltmeter Ratioon no load

Primary Connection

Reading Secondary Connection

Reading

AC 20 DE 5.85V 0.2925

AC 20 FG 7.75V 0.3875

AC 20 dg (ef linked) 6.37V 0.3185

BC 20 dg (ef linked) 7.82V 0.391

PRACTICAL 1.3-VOLTAGE AND CURRENT RATIOS ON LOAD

Procedures:

1) Make the connections to the mimic panel as shown in fig. 4.1.6. Connect the Dissectible

Transformer leads into the sockets labelled a to g on the front panel ensuring that the

identifying letters on the leads and sockets correspond.

2) Ensure all switches on the load unit are switched on and that the load switch on the

Transformer Mimic Panel is switched on.

3) Switch on the 60-121, set the primary voltage to 100V (read on the left hand voltmeter).

4) Measure the primary and secondary voltages and currents and records the results in Table

4.1.2

Results :

Primary Voltage V1 (V)

Primary Current I1 (A)

Secondary Voltage V2

(V)

Secondary Current I2

(A)

Load Resistance

(Ω)100.98 0.46 100 0.18 60

Figure 4.1.3 Figure 4.1.4

Figure 4.1.6