Running a single phase motor on VFD

dloc · Jul 3, 2002

Is there a way to run a single phase motor on a VFD so that I can get variable speed? The motor runs an industrial flap sander. Alternative is to swap out the single phase motor for a three phase but that will be difficult mechanically. No room to swap pulleys.

D. Thomas · Jul 3, 2002

Forrest Addy · Jul 5, 2002

Also no.

But look at the problem again. Three phase motors are frequently smaller than single phase for the same HP. Also study the motor catalog looking at small motor frame sizes that duplicate that of the singl ephase motor you have. Surely there's something.

George Hodge · Jul 8, 2002

Dloc,depending on the hp.of your motor,you might get by with a Variac. An adjustable AC.power supply. I have one rated at 3/4hp.used to achieve speed control of a big ventilation fan. I don't think it will work with a split phase motor. I have a smaller one on my drill press,running a 3/4hp.DC. motor,with some electronic controls.

Jeremy · Jul 12, 2002

So can someone recommend a VFD setup (controller and drive motor) for a 1-1/2 HP Jet mill/drill? I'd really dig getting away from the belt change setup. Currently I have 110/220VAC single phase available, but may be getting 3 phase this winter.

Country Bubba · Jul 13, 2002

I purchased one of
http://www.dealerselectric.com/
2HP VFD/Motor packages to go on my RF31 and have been extremely pleased with it. I just checked his web site and he now has 3 packages available 1,2,3 HP. He used to have a 1 1/2 package also, but it may be sold out. Give him a call and ask??

Usual disclaimer, just a satisfied customer

Coolhand · Mar 17, 2003

Yes, look at the Allen Bradley PowerFlex series. They have single phase units in this new series.

Forrest Addy · Mar 18, 2003

Jeremy, you'll still have to change belts even with a VFD/three phase motor drive. You need the mechanical advantage to run those operations requireing significant power.

Induction motors are constant torque devices. If, for example, your 1 HP machine is set to top speed of 2500 RPM and you wish to drill a 1/2 hole is steel at 500 RPM but turning down the VFD, you'll discover you have only about 1/5 HP available.

You'll still have to flip belts with a VFD but not as often.

Mouse23 · May 22, 2017

Puzzled.

D. Thomas said:
No

Why not? The power on the power pole is three phase. But you can decide to use one, two or three phases, dictated by your equipment needs.
So if your VFD is the 3phase "provider" and you are the client, seems to me you can decide as well.

JST · May 22, 2017

It depends on the motor. A "PSC" motor, with a start/run capacitor and no start centrifugal switch you CAN run on a single phase output type VFD.

They start at full speed, then can be varied in speed over a decent range. A regular split phase would also work, EXCEPT that the start switch would cut in if you went below about 80% of full speed, making it not very useful.

A few other non-useful motor types also work, but are limited to low power applications.

Basically the motor you have is probably one that does not usefully work.

Modelman · May 22, 2017

JST said:
It depends on the motor. A "PSC" motor, with a start/run capacitor and no start centrifugal switch you CAN run on a single phase output type VFD.

They start at full speed, then can be varied in speed over a decent range. A regular split phase would also work, EXCEPT that the start switch would cut in if you went below about 80% of full speed, making it not very useful...

I wonder... could the centrifugal switch be replaced by a timing relay? I mean, you really only need the start winding energized just long enough to determine rotation direction, then the relay could time out and reset when the motor is de-energized.

Dennis

JST · May 23, 2017

They also tend to pull a lot of start current. may not be available, even from the 1P units out there. Never tried it, only used PSC types.

It Is done for some well pumps. Turned down a bid request for a VFD design for well pump once. Didn't look cost effective. They wanted 5A or so continuous, and 45A start, IIRC.

TDegenhart · May 23, 2017

There is another variable, some of the VFD's have phase loss protection, meaning that it will fault out if not all three phases are used.

Tom

Philabuster · May 23, 2017

Mouse23 said:
Why not? The power on the power pole is three phase. But you can decide to use one, two or three phases, dictated by your equipment needs.
So if your VFD is the 3phase "provider" and you are the client, seems to me you can decide as well.

Thank you for reviving a 14 YEAR OLD THREAD. :rolleyes5:

Jraef · May 23, 2017

There are VFDs made to run single phase motors, but only PSC (and shaded pole, which is pointless anyway).

Feeding only 2 poles off of a 3 phase drive will create a current imbalance that the VFD will (should) trip on by assuming it has a defective transistor because no current is flowing through it at the right times (a VFD is constantly cross checking itself).

If you found one that would NOT trip on output current imbalance, then in theory maybe a Split Phase with a timer and relay on the output of the drive instead of using a centrifugal switch is theoretically possible, but the starting current will exceed the transistor rating, unless you so grossly over size the VFD that it would have been cheaper to just get a three phase motor and a VFD that can accept single phase input. Basically all the risk of popping your expensive VFD without much reward.

Steven-Canada · May 23, 2017

Philabuster said:
Thank you for reviving a 14 YEAR OLD THREAD.

With giberish

Search

Largest Manufacturing Technology Community on the Web

Search

Running a single phase motor on VFD

dloc

Guest

D. Thomas

Guest

Forrest Addy

Diamond

George Hodge

Aluminum

Jeremy

Hot Rolled

Country Bubba

Plastic

Coolhand

Guest

Forrest Addy

Diamond

Mouse23

Plastic

JST

Diamond

Modelman

Titanium

JST

Diamond

TDegenhart

Diamond

Philabuster

Diamond

Jraef

Titanium

Steven-Canada

Hot Rolled

Similar threads