ch 6 current transformers
5 A
What is the standard current rating for the secondary winding of a CT?
5A
What is the standard current rating for the secondary winding of a CT?
false
When current transformers are used, the main power line is inserted through the opening in the transformer. The power line acts as the primary of the transformer and is considered to be two turns.
The primary winding of a voltage transformer is connected directly across the power line. The primary winding of a current transformer is connected in series with a load.
Which of the following statements are true?
c. wrap multiple turns of wire around the jaw of the ammeter to change the secondary-scale value
An ammeter with a full-scale range of 0-6 amperes would not be able to measure accurately a current flow of 0.2 amperes. The answer to this problem is to ____.
true
Many electricians use the clamp-on type of AC ammeter.
true
The clamp-on type of AC ammeter uses a current transformer to operate.
TRUE
The secondary winding of a CT should never be disconnected from its load when there is current flowing in the primary, because an extremely high voltage can develop that can cause physical injury to personnel or could damage the transformer,
true
The secondary winding of a CT should never be disconnected from its load when there is current flowing in the primary, because an extremely high voltage can develop that can cause physical injury to personnel or could damage the transformer,
only one
To use the clamp-on type of AC ammeter, clamp the jaw of the meter around ____ of the conductors supplying power to the load.
50 A
A current transformer has a ratio of 500:5. If ten loops of wire are wound through the transformer core, how much primary is required to produce 5 amperes of current in the secondary winding?
2.5 A
A current transformer has a ratio of 600:5 and three loops of wire are wound through the transformer. If the primary current of 100 amperes flows through the windings of the transformer. How much current will flow in the secondary winding?
6.875 A
A current transformer has a ratio of 600:5 and three loops of wire are wound through the transformer.If the primary current of 275 amperes flows through the windings of the transformer. How muh current will flow in the secondary winding?
60 A
A current transformer has a ratio of 600:5. If ten loops of wire are wound through the transformer core, how much primary is required to produce 5 amperes of current in the secondary winding?
their lowest scale value is too high to accurately measure low-current values
A problem with many clamp-on ammeters is that ____.
toroid
A(n) ____ transformer is a transformer constructed with a hollow core, similar to a donut in that it has a hole in the middle.
AC ammeters
Current transformers are used to change the full-scale range of ____.
true
Current transformers differ from voltage transformers in that the primary winding is generally part of the power line.
