Accurate meaning of the PT and CT

Totally Enclosed Protect Feature and Three-phase Phase low rpm ac electric motor

Specifications
Specifications1.3-phase asynchronous motors 
2.IEC standard 
3.OEM 
4.Voltage:50HZ &60HZ;380V&415V 

5.Protection class: IP54 
 CT, CT (Current Transformer), English spelling Current Transformer, is the primary side large Current, in proportion to fit through the instrument or use the ac electric motor relay, rated Current 1 a to 5 a or the transformation of equipment. Its working principle and the transformer is similar. Also known as TA or LH (old symbols). Working characteristics and requirements: 1, a winding and high voltage circuit in series, only depends on the high pressure loop current I1, and has nothing to do with the secondary load. 2, secondary loop are not allowed to open, otherwise will produce dangerous high voltage, endangers one's personal and equipment safety. 3, CT secondary loop must have some grounding directly, prevent after the primary and secondary windings insulation breakdown of high voltage, but only a little ground. The accuracy of the 4, and transformation. Wiring forms are: the three-phase y connection completely, two-phase incomplete connection, two motor vehicle differ lift, two-phase three star connection, single-phase completely. Note: Three phase motor the current transformer for measuring core should be easy to saturated when a short-circuit, to limit the growth of secondary side current ratio; Core for relay protection, should not be saturated when a short-circuit, make the secondary side of current with the primary side current is directly proportional to increase.