Difference between Current Transformer and Potential Transformer

In this article about difference current transformer and potential Transformer. How Current Transformer and Potential Transformer works.

How do you measure volumes of AC currents and very high voltage? You will need high-level measuring devices, which literally means a huge instrument. The AC currents and the voltage change is another way of using the property. You can change the voltage or current down with the transformers whose turn ratio is well known. Then measure the step-down dimension with the normal range of equipment.

Instrument Transformer

The transformers principal amount will determine by multiplying the result with the only conversion ratio. Particularly transformed transformer with a proportion of correct turn is called an instrument transformer. The instruments are two types of Transformers.

1. Current Transformers (CT)

2. Potential Transformers (PT)

Current Transformers (CT)

The Current transformers are usually using to measure currents of high magnitude. These transformers take the current down to measure that it can measure with the normal range ammeter. There is only one or very small primary turn in a current transformer. The primary rotation can be just a conductor or a bus placed in a hollow core (as shown in Figures). The ratio of a specific turn in the secondary rotation leads to a large number of correct wounds. the current transformers currently increase the voltage during the bottom (below) voltage (increases).


The secondary flow is measuring with the help of AC ammeter. The turn ratio of a transformer is equal to:

Turns ratio =  Np/Ns  =  Vp/Vs  =  Is/Ip
The current transformers are using in a common Digital Clamp Meter application. Normally, the current transformers are expressing in their primary to secondary current proportions.

A 20: 1 ratio will mean the secondary flow of 1 ampere when the primary flow is 20 amperes. The secondary current ratings are normally 5 amperes or 1 ampere, which is compatible with standard measurement instruments.

Potential Transformers (PT)

The Potential transformer also known as voltage transformers. They are basically taking down the transformer with extremely precise turn ratio. Possible transformers high voltage down to low voltage, which can measure with standard measuring instruments. Their transformers will have a large number of winding turns in primary and small numbers of secondary part.

Potential transformers are usually expressing from the primary to secondary voltage ratio. For example, 5: 1 PT means that the voltage in the secondary is 50 volts when the primary voltage is 250 volt.

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