Write any four differences between CT and PT.

1 Answer

Answer :

CT
PT
CT corresponds to current transformer
PT corresponds to potential transformer
CT primary is connected in series with load and secondary winding is connected to a low range ammeter.
PT primary is connected in parallel with high voltage of load and secondary winding is connected to a low range voltmeter. 
Secondary winding is never open circuited when primary carries current.
No such restrictions are there for PT connection.
Used for Range extension of ammeter, wattmeter & energymeter.
Used for Range extension of voltmeter, wattmeter.
Specified by their burden and nominal current ratio.
Specified by their burden and nominal voltage ratio.
Measured value of current = (reading of low range ammeter) x CT ratio
Measured value of voltage = (reading of low range voltmeter) x PT ratio
It is a step-up transformer.
It is a step-down transformer

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