From the first picture:
Current transformation ratio 300A to 5A.
Nominal power 5 VA.
Nominal voltage 660V
Accuracy 0.5%
"Current transformation ratio 300A to 5A."
Not unless that transformer is going to step the voltage UP by a factor of 300/5!
Every current transformer that I've ever seen measures amperage but gives a
voltage output. In this case 5 volts AC out when the current through it is 300 Amps. The output
voltage is directly proportional to the
current in the conductor that passes through the center hole. 2 1/2 VAC output for 150 amps, so on and so forth.
660V is also not the nominal voltage but the MAXIMUM safe voltage.