How Many Current Transformer Ratios Are There?
How to calculate the transformation ratio of the current transformer
The current method to measure the transformation ratio of the current transformer is a traditional test method. At present, all power plants, substations, etc. basically adopt this method. According to the transformation ratio of the standard current transformer, the primary side current of the tested current transformer can be calculated.
The magnification of the current transformer is related to the transformation ratio of the transformer, which is marked on the nameplate of the transformer.
For example: the primary rated current is 100A, and the secondary rated current is 5A, then the multiplier of the transformer is 100/5=20
The primary rated current is 200A, and the secondary rated current is 5A, then the multiplier of the transformer is 200/5=40
The so-called magnification is the transformation ratio.
For example: 30/5 current transformer, now 5 turns through the core, the single rate of electricity bill is 6.
Primary turns: 1, current ratio: 100/5=20 times
Primary turns: 2, current ratio: 50/5=10 times
Primary turns: 4, current ratio: 25/5=5 times
Primary turns: 5, current ratio: 20/5=4 times
Primary turns: 10, current ratio: 10/5=2 times.
What are the ratios of current transformers?
There are a total of 25 common transformation ratios of current transformers. As follows:
Secondary side: 5A, 1A
Primary side: (A): 15, 20, 25, 30, 40, 50, 60, 75, 100, 150, 200, 250, 300, 400, 500, 600, 750, 800, 1000, 1200, 1500, 2000, 2500 etc.
Common capacities of DC screen maintenance-free battery packs: 12, 24, 38, 40, 60, 65, 80, 100, 180, 300, 500A h, etc.
A current transformer is an instrument that converts a large current on the primary side into a small current on the secondary side for measurement based on the principle of electromagnetic induction. A current transformer consists of a closed iron core and windings. Its primary side winding has few turns and is connected in the line of the current to be measured.
The number of turns of the secondary winding is relatively large, and it is connected in series in the measuring instrument and the protection circuit. When the current transformer is working, its secondary circuit is always closed, so the impedance of the series coil of the measuring instrument and the protection circuit is very small. The working state of the current transformer is close to a short circuit. The current transformer is to convert the large current on the primary side into a small current on the secondary side for measurement, and the secondary side cannot be opened.
