Advantages of Instrument Transformers

Advantages of Instrument Transformers Points : Advantages of Instrument Transformers It will be realized that instrument transformers in a.c. circuits, act as devices for increasing the range of instruments; they take the place of high series resistors for voltmeters and shunts for ammeters. They have the following advantages.

1. The power loss in a transformer is small, whereas the power loss in a resistance shunt or multiplier may be considerable.
2. The instrument operated may be well removed from all high-voltage conductors. In addition, the instrument circuit is insulated from the high-voltage conductors and may be carthed. These are important advantages from the point of view of safety. No high-voltage insulation is required in the instruments.
3. A few Standard ranges for voltmeters and standard ranges for ammeters may be used for all circuit currents and voltages by the use of transformers of suitable ratio. Typical values are 5A and 11OV.
4. The instrument transformer are used in conjunction with protective devices, is of great importance but out of the scope of this chapter.
5. If necessary, several instruments can be operated from a single transformer.
6. The cost of the instrument (or meter) together with the instrument transformer is less is less than that of the instrument alone if it were to be insulated for high voltages.