The structure of the voltage transformer is shown in Figure (a). Its function is to extend the range of the AC voltmeter and isolate the high voltage from the electrical workers.The operating principle is similar to the no-load condition of ordinary transformer.When in use, the high-voltage winding with more turns should be bonded to the power supply line that needs to measure its voltage, while the low-voltage winding with less turns should be connected to the voltmeter, as shown in figure (b) below.
Since U1/U2=K, U1=KU2, it can be seen that the voltage of the high-voltage line is equal to the product of the voltage measured by the secondary side and the transformer ratio.When the voltmeter is used with a dedicated voltage transformer, the scale of the voltmeter can be marked according to the voltage on the high-voltage side of the voltage transformer. In this way, the voltage value of the high-voltage line can be read directly from the voltmeter without conversion.
Generally, the rated voltage of the secondary side winding of the voltage transformer is designed with the same standard value of 100 volts.Therefore, voltage transformers used in different voltage classes of circuits have different transformer ratios, such as 1000/100, 600/100 and so on.
J Voltage transformer model：
D Single phase
Z Casting type
F With residual voltage winding
7 Design Number
10 Voltage class（kV）
GYW1 Plateau Dirty