本帖最后由 td456 于 2010-4-14 12:28 编辑 , D* C& P4 P" Y B
: u0 k( \9 s4 F& x9 AWe all know that if you want to change the rotation of a three phase AC motor.3 D- A! f3 q, q9 j* ?9 I5 o6 v# n
Just swap any of the two phase leads. & O3 q6 `. _8 S# }$ }But for VFD application you need to do the swap after the inverter. ; {- X1 M3 q, J$ }; jIf you swap the leads before the inverter, it will not work.
Yes, Good point. ; m- D9 u$ k1 O% V& Z& L9 H " y$ S2 y1 Q+ z- O& v4 VAs the principal of the VFD works, bascially from AC to DC, then DC to AC. ) F0 u$ W# q! G9 z& q: N0 D
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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.* ^' c2 R* p) A. F4 T( w
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The only thing you can change the rotation of the motor is the output side of the VFD, NOT the input of the VFD.