Aiph5u
July 16, 2024, 11:24am
6
Hey Dennis,
anyway, you should always rely on the input current rating on the nameplate and the manual of the VFD. And if the VFD’s input current rating is willingly omitted and kept secret by the manufacturer, like in these examples here , I would never buy such a VFD. It’s not serious.
Here you can see the nameplate of my VFD and Michael’s, both are VFDs for 2.2 kW 220 V spindle:
Look at the input current, and at the output current. The output current refers to the current per phase !
As you can see on the VFD’s nameplate that Michael shows above, it delivers max. 12 A three-phase output current to a spindle motor, and in order to do this, it draws up to 24 A on a single-phase supply line . In the manual, a 30 A fuse/MCB is recommended. That is because the output current rating applies to three phases that are delivered on three wires simultanely, each rotated by 120°. If you look at mathematics of three-phase electricity , you can calculate how much current that is if you sum up all the three currents at a certain moment in time:
Image: Three-phase electricity: Each wave is shifted by 120°.
1 Like