Most current transformers have a the standard secondary rating of 5 amps with the primary and secondary currents being expressed as a ratio such as 100/5.
What are the specifications of transformer?
- 11 kV.
- 400 V. Nominal Voltage. ...
- 10.1 Rated Power. The continuous rating of the distribution Transformers shall be 100kVA, 250 kVA, 400 kVA and 630 kVA. ...
- 10.2 Overload Capacity. ...
- 10.3 Impedance Voltage. ...
- 10.4 Short Circuit Performance. ...
- 10.5 Flux Density. ...
- 10.6 Noise Level.
What is STC rating of current transformer?
Standard times for which the CT must be able to carry rated short-time current (STC) are 0.25, 0.5, 1.0, 2.0 or 3.0 seconds. A CT with a particular short-time current/ time rating carries a lower current for a longer time in inverse proportion to the square of the ratio of current values.Dec 3, 2018
How are current transformers specified?
They are defined by their ratio, power and accuracy class. Their class (accuracy as a function of CT load and of overcurrent) is chosen according to the application. ... Current transformers are thus expected to have an Accuracy Limit Factor (ALF) that is usually fairly high.Dec 5, 2015
How is current transformer rating determined?
Calculate the current from the voltage/amperage (VA) specification or the power rating designated in watts. Both figures mean basically the same thing. Divide either the VA or wattage rating of the transformer by the voltage. This will give you the current rating.Mar 13, 2018
How is CT ratio calculated?
The CT ratio is the inverse of the voltage ratio. In this example, the voltage ratio is 1:5, so the CT ratio is 5:1. This means the current level is stepped down 5 times where, if the primary current is 200 amps, the CT output is 40 amps.Aug 7, 2017
What is CT ratio?
The CT ratio is the ratio of primary current input to secondary current output at full load. For example, a CT with a ratio of 300:5 is rated for 300 primary amps at full load and will produce 5 amps of secondary current when 300 amps flow through the primary.
What is CT ratio in transformer?
The CT ratio is the ratio of primary current input to secondary current output at full load. ... Current Transformers (CTs) can be used for monitoring current or for transforming primary current into reduced secondary current used for meters, relays, control equipment and other instruments.
How do I choose a current transformer?
- Type: opening (split-core) or non-opening (solid-core)
- Accuracy: monitoring or revenue grade.
- Size: must be large enough to fit around the conductor being monitored.
- Rated Amps.