Order of work implementation

 

1. To familiarize with the design of the investigated transformer and equipment of the laboratory setting. To write down technical data of measuring devices to protocol.

To assemble a plant for research of transformer by a chart, represented on fig. 1.8.


2. To research open circuit mode; it is needed for this purpose

to turn off by the switch S1 a load resistance ZL. Setting by means of autotransformer the least of possible voltages, to plug a transformer in a network. Fluently increasing voltage, to take off the readings of devices at the next values of voltage:

0,25U1nom; 0,5U1nom; 0,75U1nom; U1nom; 1,2U1nom.

 

Fig. 1.8

 

To bring the results of measuring and calculation data to the table. 1.1

Table 1. 1

Measuring Calculation
U1, V I0 А U20 V P0 W cosφ0 k Zm, Ω Xm, Ω Rm Ω I0/I1nom
                   

 

3. To research experience of short circuit, for what it is needed at the switched off transformer to include in a chart (fig. 1.8) ammeters with the limit of measuring, which equals to 1,5∙Inom. To change the limit of measuring to the wattmeter to the necessary limits. To short out secondary winding, closing switches S1 and S2. Before powering on the transformer to reduce source voltage up to the zero.

Plugging a transformer in a network, increasing the supply voltage consistently to set the following values of current: 0,1Inom; 0,25Inom; 0,5Inom; 0,75Inom; Inom;1,2Inom.

To bring the results of measuring and calculations to the table. 1.2

4. To research transformer in an operating duty at the active, inductive and capacitive load.

At dead source of feed to connect active load resistance to transformer. For this purpose to close the switch S1 and turn off S2 (fig. 1.8).

Table 1.2

Measuring Calculation
U1, V I1, А P1 W I2 А kL = I1 / I1nom U1 = U1/U1nom cosφk Rk,Ω Zk Ω Xk Ω
                   

 

Before powering on the transformer its voltage must be minimum possible, and load resistance − maximal.

To increase the supply voltage up to the rated value U1 = U1nom. Diminishing resistance of load, consistently to set the next values of current І2 : 0; 0,25I2nom; 0,5I2nom; 0,75I2nom; I2nom;1,2I2nom. Primary voltage here to support nominal U1nom.

Like to research transformer at inductive and capacitive character of load.

To bring the results of measuring and calculations to the table. 1.3.

Table 1.3