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Forum Index : Other Stuff : VFD’s and AC servos

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Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 5111
Posted: 04:14am 30 Nov 2018
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I have a few AC servo motors and DC treadmill motors, all in the range of 1500 to 3500 watts, and no way to drive them.

On ebay there are a lot of Huanyang 2.2kW VFD's for around $160 delivered, and I see a lot of people are using them to drive workshop tools, like band saws, etc.

I have zero experience with VFD's, a bit of internet searching tells me, on one site, a VFD can drive a AC servo, but another site says it wont work, or works poorly. I was wondering if anyone on the forum has used a VFD on a AC servo, and how well it worked?

I've also read a VFD can drive a single phase AC induction motor, if you separate the start and run windings and connect them as a sort of 2 phase motor. But again, does this work and how well?

I also thought maybe a VFD could be used to drive a treadmill motor, as they can vary the output voltage through PWM, if I combined the 3 phase VFD output through a 3 phase rectifier to feed the DC motor. But I suspect the VFD uses feedback from the motor to adjust its torque curve and timing, so this may not work.

Like I said, I have zero experience with VFD's.

Glenn
The best time to plant a tree was twenty years ago, the second best time is right now.
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Chopperp

Guru

Joined: 03/01/2018
Location: Australia
Posts: 1090
Posted: 12:47pm 30 Nov 2018
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Hi Glenn

Not too sure as to what you want but SC did a speed controller for induction motors a few years ago here

Maybe helpful if you have access to the full article
ChopperP
 
ryanm
Senior Member

Joined: 25/09/2015
Location: Australia
Posts: 202
Posted: 05:35am 01 Dec 2018
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From my understanding of it a servo is a closed loop motor control system more than a particular motor configuration. So if the ac servos are induction motor based they will also contain a controller, position encoder and a VFD that converts an incoming pulse signal into a rotational position. Although depending on the model this functionality could have been in a control box separate to the motor.

For the DC motor I would slap together a cheap PWM driver. One of Mad's new GTI controller boards would do well I would guess.
 
Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 5111
Posted: 06:42am 01 Dec 2018
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What I want to do is drive a AC servo motor as a motor, without the need of the servo ability. I have several of these motors gathering dust, and was wondering if anyone has any experience using the Huanyang VFD's as a driver. The Huanyang VFD is a single phase AC to 3 phase AC driver for 3 phase induction motors. I have read VFD's can work with AC Servo's, but I've also read they wont.

Glenn
The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ
 
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