A Tip on changing 3 phase AC motor rotation

td456

# e7 V+ h7 Q- V' j  e! @We all know that if you want to change the rotation of a three  phase AC motor.
5 t6 |+ R  L: h# z. nJust swap any of the two phase leads.
2 o" V  _* ?: c, b* m# rBut for VFD application you need to do the swap after the inverter.
' L3 f7 d9 O1 }) f' ^If you swap the leads before the inverter, it will not work.

nw123

go go go

MrElectrician

Yes, Good point.

As the principal of the VFD works, bascially from AC to DC, then DC to AC.
8 h* v: d5 {0 a# N( \' G6 H" e
The phase rotation of the output of the VFD connecting to the motor is based on the sequence "open" or "close" controlled by the inverter pre-set inside; any changes to the phase rotation of the feeder will not affect the DC rotation, as DC is NO phase at all.

5 d  ^% B2 M5 c3 N* jThe only thing you can change the rotation of the motor is the output side of the VFD, NOT the input of the VFD.

jiodiangong

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