To work this out you will need to know the current that is travelling through the device.
You can then find the number of volts by dividing the power (watts) by the current (amps).
45 volts
1000
230 Volts
4160 volts
1.55 volts
0.016 volt
Zero volts.
230 volts
neither...it should have 14.63 volts
3 Kv = 3,000 volts.
12 volts DC
1 megavolt = 1,000,000 volts