What is the role of Power Current TransformerCT
May 13, 2021| Since the full-scale current of the meter head is 5A, the different indication scales on the dial surface indicate the line current, so when the current on the line exceeds the maximum current allowed by the meter head, a suitable Power Current Transformer should be used. Changed. The previous friend is right. The Power Current Transformer is equivalent to a step-up transformer, so the current becomes smaller when the voltage rises. In this way, the actual current on the primary side can be measured by choosing a transformer with a suitable "conversion ratio". How much is it;
The so-called suitable converter ratio means that the rated current of the primary side of the transformer must be the same as the full-scale current of the ammeter (for example, for a 400:5 transformer, an ammeter with a full-scale current of 400A should be used). Yes, the transformer on the secondary side of the line (the side connected to the ammeter) is absolutely not allowed to open (disconnect the wiring), otherwise there may be danger or accidents due to the high voltage on the secondary side.
Transformer is a special transformer, which is widely used in power supply systems to supply voltage or current coils of measuring instruments and relays.
The role of transformer:
(1) Change the high voltage and high current of the primary circuit into the standard low voltage and small current of the secondary circuit, standardize and miniaturize the measuring instrument and protection device, and make the structure light and cheap, and easy to install in the screen .
(2) Isolate high voltage circuits. There is no electrical connection between the primary side and the secondary side of the transformer, only the magnetic connection. The secondary equipment is isolated from the high-voltage part, and the secondary side of the transformer is grounded, thereby ensuring the safety of the equipment and the person. It should be noted that the transformer on the secondary side of the line (the side connected to the ammeter) is absolutely not allowed to open (disconnect the wiring), otherwise there may be danger or accidents due to the high voltage on the secondary side.