i would like to ask about battery charger i saw at work :) the plate on charger says:

Input voltage 3 phase ac

  • Min 400v
  • Nominal 400-415v
  • Max 456v

Input current

  • 20A


  • 110v DC 9kW
  • 28v DC 3kW

Now if we do simple math with no losses input is 9012W. How can be output 12kW?

Or the manufacturer gives these readings as separate? When we charge only one kind of battery?

  • \$\begingroup\$ The plate is saying that the device is capable of outputting more power when the voltage is set higher. \$\endgroup\$ – supercat Jan 30 '16 at 0:15
  • \$\begingroup\$ Yea i could get it, but i tried to ask one of "smart" guys and he started saying something about power transformers and so on and haven't finished that. \$\endgroup\$ – Martynas Jan 30 '16 at 0:17
  • \$\begingroup\$ From the data you give input power is 14400W \$\endgroup\$ – user1582568 Jan 30 '16 at 0:26

There's a factor of \$\small \sqrt 3\$ for three phase

  • 1
    \$\begingroup\$ Missed that one :)) \$\endgroup\$ – Martynas Jan 30 '16 at 0:31

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