CT's and ammeters

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GoldDigger

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For what purpose?
If the voltage drop of each ammeter is low enough you could wire them is series so that they both gave an identical and correct reading.
If you try to put the meters in parallel the sum of the two readings could be the CT current, but the current split between the two would not be controllable.

Tapatalk!
 

SG-1

Senior Member
It is quite common in MV Switchgear to wire multiple devices in series in a current circuit. The circuit designer just needs to watch that the burden does not exceed the limit for the CT being used.
 
For what purpose?
If the voltage drop of each ammeter is low enough you could wire them is series so that they both gave an identical and correct reading.
If you try to put the meters in parallel the sum of the two readings could be the CT current, but the current split between the two would not be controllable.

Tapatalk!

Will there be an issue with wire length?
 

Phil Corso

Senior Member
Swaso...

"Burden" is the total equivalent impedance of the electrical protective and measuring devices connected to the transformer(s) secondary. Connecting lead lengths are also included. Device impedances are usually furnished by the device manufacturer.

Typically, one selects a transformer having a capacity that equals or exceeds the computed burden. Burden could be expressed in Volt-Amperes @ some load angle, or resistance and reactance. All xfmr designs are required to meet specific 'Accuracy' standards. Of course there are a myriad of standards depending on the country of origin.

Regards, Phil Corso
 

Phil Corso

Senior Member
Swasco...

"Burden" is the equivalent impedance of the electrical protective and measuring devices connected to the transformer(s) secondary. The connecting leads, hence length, are also included. Device impedances are furnished by the device manufacturer.

Typically, one selects a transformer having a capacity that equals or exceeds the computed burden. Burden could be expressed in Volt-Amperes @ some load angle, or resistance and reactance. All xfmr designs are required to meet specific 'Accuracy' standards. Of course there are a myriad of standards depending on the country of origin.

Regards, Phil Corso
 

djohns6

Senior Member
Location
Louisiana
It is quite common in MV Switchgear to wire multiple devices in series in a current circuit. The circuit designer just needs to watch that the burden does not exceed the limit for the CT being used.
Very common in high voltage substation relaying as well .
 
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