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Using VFD's with single phase motors
liam.mccaffrey - 8/7/17 at 10:30 PM

Does anyone have any experience using VFD's as speed control on single phase motors.

I have a 1.1kw single phase motor which I need to be able to alter the speed of.

Thanks in advance

Liam Mc

Toys2 - 9/7/17 at 09:23 AM

quote:
Originally posted by liam.mccaffrey
Does anyone have any experience using VFD's as speed control on single phase motors.

I have a 1.1kw single phase motor which I need to be able to alter the speed of.

Thanks in advance

Liam Mc


Unfortunately, You can't use a VSD with single phase motor, the option there is to swap the motor for a 3 phase 220V and then use an invertor with that

MikeRJ - 9/7/17 at 05:10 PM

quote:
Originally posted by Toys2
Unfortunately, You can't use a VSD with single phase motor, the option there is to swap the motor for a 3 phase 220V and then use an invertor with that


Single phase VFDs are definitely available, though single phase motors have significant disadvantages over three phase so there would need to be a compelling reason not to fit a 3 phase motor and VFD.

SteveWalker - 9/7/17 at 05:35 PM

Sell the single phase motor and buy a three phase one? At that power you could run the VFD from a single phase supply still.

Alternatively, but physically more complicated, a variable speed pulley system - Variable speed pulley system

liam.mccaffrey - 9/7/17 at 06:36 PM

Anyone want to buy a brand new 1.1kw single phase motor

Toys2 - 10/7/17 at 10:13 PM

quote:
Originally posted by MikeRJ
quote:
Originally posted by Toys2
Unfortunately, You can't use a VSD with single phase motor, the option there is to swap the motor for a 3 phase 220V and then use an invertor with that


Single phase VFDs are definitely available, though single phase motors have significant disadvantages over three phase so there would need to be a compelling reason not to fit a 3 phase motor and VFD.


Yes there are single phase VSD's but they drive 3 phase motors. As far as I know, it's not possible to control a single phase motor due to the requirement of phase angle generated by the capacitor start

coyoteboy - 11/7/17 at 12:27 PM

Single phase induction motor requires a cap to start to give a temporary phase difference between the two fields.
It will run at the speed given by the feed frequency.
You could attempt to run a single phase motor from a 3 phase VFD (just using one phase output) but it's a total kludge and might trip out the (unevenly loaded) VFD.

MikeRJ - 19/7/17 at 12:54 PM

quote:
Originally posted by Toys2
quote:
Originally posted by MikeRJ
quote:
Originally posted by Toys2
Unfortunately, You can't use a VSD with single phase motor, the option there is to swap the motor for a 3 phase 220V and then use an invertor with that


Single phase VFDs are definitely available, though single phase motors have significant disadvantages over three phase so there would need to be a compelling reason not to fit a 3 phase motor and VFD.


Yes there are single phase VSD's but they drive 3 phase motors. As far as I know, it's not possible to control a single phase motor due to the requirement of phase angle generated by the capacitor start


As I said it' most definitely is possible, and they are available. I suspect a capacitor start motor would not be suitable, or at least would limit the available speed adjustment at startup, but a shaded pole or split capacitor motor would be ok.

http://www.invertekdrives.com/variable-speed-drives/optidrive-e2-single-phase/
https://www.wolfautomation.com/blog/vfds-for-single-phase-motors/