Suggestions on 1PH motor connected to VFD with 3PH output
Suggestions on 1PH motor connected to VFD with 3PH output
(OP)
I have connected a 1PH 240V 1.1kw motor to a VFD which has 1PH 240V input and 3PH 240V output. I disconnected the cap and can run the motor but it is drawing excessive current and is not getting up to full speed? Any ideas on how to rectify this would be appreciated.





RE: Suggestions on 1PH motor connected to VFD with 3PH output
What you are attempting will never run correctly. You're violating a fist-full of physical requirements and should soon be needing a new VFD.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Suggestions on 1PH motor connected to VFD with 3PH output
RE: Suggestions on 1PH motor connected to VFD with 3PH output
Is there a reason why you are running a Single Phase Motor ?
If it is cost then replacing the VFD will cost you more int he long run !!
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RE: Suggestions on 1PH motor connected to VFD with 3PH output
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Suggestions on 1PH motor connected to VFD with 3PH output
But I learn...
RE: Suggestions on 1PH motor connected to VFD with 3PH output
If the 1-phase motor has starting caps then it is not suitable for a VFD speed control application, even if you get a different VFD.
It is possible to control certain types of 1-phase motors on a 3-phase VFD by connecting 3 or a multiple of 3 motors to the VFD.
RE: Suggestions on 1PH motor connected to VFD with 3PH output
ht
RE: Suggestions on 1PH motor connected to VFD with 3PH output
#1 motor should be a perminant split capacitor type
#2 motor should NOT have a start capacitor or start winding or centrifugal switch
#3 motor should NOT be used in an application where it must have high starting torque or start under load (ie air compressor or power tools)
Really one of the only times you can use a vfd with an induction motor is in a fan/blower type application.
You really should use a single phase vfd in this type of application when possible. A single phase vfd will often remove the capacitor that is built into the motor and generator the main and phase (shifted) waveforms and allow speed control and reversing. The other alternative is to use one that generates the main waveform only and use the capacitor in the motor. The other gotcha with single phase vfd is that the efficiency and torque is no where near flat compared to a 3ph motor. torque and efficency will suffer greatly at low and higher speeds, usually more of a problem as motor frame size increases. Like I said best used in a fan/blower application where this will not be an issue. hope this helps
RE: Suggestions on 1PH motor connected to VFD with 3PH output
Thanks again