# Your question: What is the purpose of polarity dots in a transformer?

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## What is the importance of polarity in transformer?

Transformer polarity is fundamental to grasping how transformers function and how they’re utilized. Understanding polarity is essential to properly paralleling single-phase transformers and connecting instrument transformers (current and potential) to metering devices and protective relays.

## What do you mean by polarity marking of transformer?

Transformer Polarity refers to the relative direction of the induced voltages between the high voltage terminals and the low voltage terminals. … Instrument Transformers (PT’s and CT’s) and large substation transformers are Subtractive Polarity, so the H1 and X1 Bushings will be on the same side of the transformer.

## Is polarity important when connecting to current transformers?

Polarity is very important for the operation of transformers and protection equipment. A clear understanding of polarity is useful in understanding and analyzing transformer connections and operations as well as testing protection relays and systems.

## Does polarity matter on AC transformer?

An AC current polarity is changing time to time, with periodical time. That’s why you know there is 60Hz system, mean that the polarity change 60 times per second. Or 50Hz in IEC. So the polarity it is no matter again.

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## What is Dot in current transformer?

The dot only serves as an indication of the side of the current transformer intended to face the source of electricity, or line side, the high side. The dot should face that high side, the source of electricity.

## What is the dots appearing at one end of each winding tell about?

The placement of these dots next to the ends of the primary and secondary windings informs us that the instantaneous voltage polarity seen across the primary winding will be the same across the secondary winding.

## Why do we need a dot convention in mutual induction?

As we have already told that whether the mutually induced emf would be additive or subtractive depends on the relative polarity of the mutually coupled coils. The relative polarity of two or more mutually coupled coils is denoted by dot convention.

## What do the dots shown beside the terminal leads of a transformer represent on a schematic?

¦ Polarity dots are often added to schematic diagrams to indicate transformer polarity.