Low Voltage AC 0.66kv Residual Current Transformer (CT) is used to transform the high AC current to small easily manageable values.
They are connected with the panel meter or relay and they can help to measure the current or protect the equipment.
Before connecting the residual current transformer, the phase line, N line and PE line in the power grid should be distinguished. The phase line and the N line must pass through the residual current transformer together, and the PE line cannot pass through the transformer. In the system, if the N line does not pass through the transformer together with the phase line, once the three-phase load is unbalanced, the N line will have a current flowing, and the detector detects the current signal, that is, a malfunction occurs. The N lines between different loops should not be connected at multiple points or repeatedly grounded, otherwise it will cause malfunction, and the leakage current value will be greater than the set value when the system is running, and an alarm will occur. If the PE line passes through the transformer together with the N line and the phase line, it will also cause the detector to reject or malfunction.
When installing the residual current transformer, it is necessary to pass the three-phase wire and the N wire through the same transformer. Therefore, the selection cannot be done in the way of conventional transformers. According to the specifications of copper bars or cables, determine the size of the inner hole, and finally select the type.
