Terminology question....
- Thread starter pridelion
- Start date
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jwelectric
Senior Member
- Location
- North Carolina
Re: Terminology question....
current tap, captain tom, cookie trap, or maybe "Cee Tee"
current tap, captain tom, cookie trap, or maybe "Cee Tee"
Ed MacLaren
Senior Member
Re: Terminology question....
Current Transformer
Current Transformer
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Re: Terminology question....
If it is for measurement of current, then as Ed said, current transformer. If it is for looking inside your body, then cat scan.
If it is for measurement of current, then as Ed said, current transformer. If it is for looking inside your body, then cat scan.
allenwayne
Senior Member
Re: Terminology question....
Cat scans,don`t flinch or you have to do it all over again
Cat scans,don`t flinch or you have to do it all over again
charlie tuna
Senior Member
- Location
- Florida
Re: Terminology question....
"current transformer" --- a big coil of wire!
two wires to hook up! they are rated and designed in size and the number of turns to have a five amp output at their rated current. an example: if you had a big piece of switchgear rated at 4000 amps, the incoming bus or cables would past through C.T.'s (current transformers).they would be rated at 4000 amps. if the current flow was 2000 amps coming into the switchgear the C.T.'s induced current flow would be 2.5 amps. at 4000 amps the C.T's output would be 5 amps. this is a ratio. they make "split" C.T.'s that allow you to install them without opening up the circuit you want to monitor or meter. the "split C.T." is not as accurate as the one piece C.T., but very close!
"current transformer" --- a big coil of wire!
two wires to hook up! they are rated and designed in size and the number of turns to have a five amp output at their rated current. an example: if you had a big piece of switchgear rated at 4000 amps, the incoming bus or cables would past through C.T.'s (current transformers).they would be rated at 4000 amps. if the current flow was 2000 amps coming into the switchgear the C.T.'s induced current flow would be 2.5 amps. at 4000 amps the C.T's output would be 5 amps. this is a ratio. they make "split" C.T.'s that allow you to install them without opening up the circuit you want to monitor or meter. the "split C.T." is not as accurate as the one piece C.T., but very close!
Re: Terminology question....
Just another note, I'm sure if you've wired them up before you know this. Never leave the secondary of a CT (Current transformer) Open. I know what happens if you do that, not sure what happens if you leave the wires open for a Cat Scan, maybe just doesn't work?
Just another note, I'm sure if you've wired them up before you know this. Never leave the secondary of a CT (Current transformer) Open. I know what happens if you do that, not sure what happens if you leave the wires open for a Cat Scan, maybe just doesn't work?
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: Terminology question....
The ?Cat? in ?Cat Scan? is ?Computed Axial Tomography.?
The ?Cat? in ?Cat Scan? is ?Computed Axial Tomography.?
- Location
- Mission Viejo, CA
- Occupation
- Professional Electrical Engineer
Re: Terminology question....
In fact its a Code violation if you do (110.23)
Re: Terminology question....
You know Bob I hate to admit it I'm so unfamiliar with the code I did not know that. I just learned it (luckily not by my own experience). Learned the theory a long time ago, but seen the results, if you want to know what happens this is where you can use the smoke theory as in one of the other threads on here, and loose electrons flowing out of the ends of wires, or is it darkons getting into the ends of wires?
You know Bob I hate to admit it I'm so unfamiliar with the code I did not know that. I just learned it (luckily not by my own experience). Learned the theory a long time ago, but seen the results, if you want to know what happens this is where you can use the smoke theory as in one of the other threads on here, and loose electrons flowing out of the ends of wires, or is it darkons getting into the ends of wires?
charlie tuna
Senior Member
- Location
- Florida
Re: Terminology question....
the new C.T.'s have a small resistor wired across the output terminals which prevents a high voltage buildup in the coil. this allows you to open the connection without problems.
the new C.T.'s have a small resistor wired across the output terminals which prevents a high voltage buildup in the coil. this allows you to open the connection without problems.
Re: Terminology question....
Charlie T, surely you aren't you saying because a resistor is present you can throw normal precautions aside are you?
I know you aren't, but let's not let some one misinterpret a post to imply this safety measure as full proof.
Roger
Charlie T, surely you aren't you saying because a resistor is present you can throw normal precautions aside are you?
I know you aren't, but let's not let some one misinterpret a post to imply this safety measure as full proof.
Roger
charlie tuna
Senior Member
- Location
- Florida
Re: Terminology question....
roger,
i am certainly saying if you purchase a C.T. that has the resistor built in to the coil you can open the secondary without worrying about voltage building up in the secondary because it will be disapated by the little resistor. this is the reason the resistor is installed!!!
roger,
i am certainly saying if you purchase a C.T. that has the resistor built in to the coil you can open the secondary without worrying about voltage building up in the secondary because it will be disapated by the little resistor. this is the reason the resistor is installed!!!
charlie
Senior Member
- Location
- Indianapolis
Re: Terminology question....
110.23 Current Transformers. Unused current transformers associated with potentially energized circuits shall be short-circuited.
No exception exists for a resister.
110.23 Current Transformers. Unused current transformers associated with potentially energized circuits shall be short-circuited.
No exception exists for a resister.
charlie tuna
Senior Member
- Location
- Florida
Re: Terminology question....
i deal with C.T.'s often in data recording functions, and with sub metering. almost any current carrying device in our trade requires caution and knowledge in safe handling---everything from a duplex receptacle to a 4000 amp transfer switch. they are all different just like C.T.'s! i mention the fact that new C.T.'s have internal resistors since we will run into C.T's without shunt terminals on them and then they not know what they are up against. safety and common sense should never is overlooked in our trade -- but knowledge of new equipment allow tradesmen to use common sense!!!!!!!
i deal with C.T.'s often in data recording functions, and with sub metering. almost any current carrying device in our trade requires caution and knowledge in safe handling---everything from a duplex receptacle to a 4000 amp transfer switch. they are all different just like C.T.'s! i mention the fact that new C.T.'s have internal resistors since we will run into C.T's without shunt terminals on them and then they not know what they are up against. safety and common sense should never is overlooked in our trade -- but knowledge of new equipment allow tradesmen to use common sense!!!!!!!
Re: Terminology question....
Have dealt with current transformers on many occasions.
For metering in low, medium, & high voltage equipment. Also for protective relaying in medium & high voltage equipment.
A fairly common method is to wire the CT's to "short-circuiting-type terminal blocks".
With the use of "thumbscrews" at these term. blocks, the CT secondary can easily be shorted out while making any wiring modifications.
If their were a resistance strapped across the secondary, I believe it would need to be taken out of the circuit at the appropriate time.
Have dealt with current transformers on many occasions.
For metering in low, medium, & high voltage equipment. Also for protective relaying in medium & high voltage equipment.
A fairly common method is to wire the CT's to "short-circuiting-type terminal blocks".
With the use of "thumbscrews" at these term. blocks, the CT secondary can easily be shorted out while making any wiring modifications.
If their were a resistance strapped across the secondary, I believe it would need to be taken out of the circuit at the appropriate time.
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