120 V AC Single Phase Input and 120 V AC Single Phase Output VFD

Why not just use a variable size pulley with a sliding motor frame mount....?

https://www.grainger.com/product/DART-CONTROLS-Variable-AC-Voltage-Supply-5JPF3

I considered that at first, but I wanted to be able to adjust the speed on-the-fly without stopping to make adjustments.

If all else fails, that may be my fall back position with an adjustable idler instead of a sliding base.

I know they make totally mechanical adjustable drives that can be adjusted while in motion, but they are too expensive for this application.

You can't turn it by hand to get the right speed? ...put a hand crank on that bad boy...count the rpm's...

I've got one of those, but my wife is using it to churn butter.

I suppose could borrow one from the old John Deere B out in the shed.

I heard they are making a new tractor now;no seat,no steering wheel....for the farmer that has lost his arse and doesn't know which way to turn..

Take the drive pulley system from the top of a drill press.

Easy to change speeds and very inexpensive.

Didn't snowmobiles have a continuously variable pulley system?

My Canadian Tire wood turning lathe has a continuous variable pulley system.

From what I read, single-phase motors are designed for a fixed frequency and are not compatible with VFDs.

https://electronics.stackexchange.com/questions/235212/can-you-use-a-vfd-to-run-a-capacitor-start-motor

I bet you could find an old treadmill motor (DC) and controller that would do what you want. Maybe buy an old used treadmill fairly cheap...

Or you could do that.

Yeah....

Had to price a 2 hp setup recently. AC tech (Lenze) and ABB were within $50 of each other, although with ABB the keypad was separate. The hardest part was getting the counter guy to understand what I was looking for!

Try reactance control. Form the hot lead into a coil. Find appropriate u metal core to insert into coil to control current. Lots of things can be controlled this way.
Or, use a magnetic amp configuration, and use a small DC current to control the power feed.

These control techniques are old, simple, reliable, and can survive a lot of abuse.

https://www.wolfautomation.com/blog/vfds-for-single-phase-motors/

If your motor has capacitor start that doesn’t switch out after up to speed, you should be able to make it work properly using volts/Hz compensation. This is one offering for $200 for up to 1 hp caught my eye, I've run across US made 1 phase output VF inverters a few years ago that are OEM boards designed to be integrated into equipment, but this one looks like it’s all set to go.

http://www.gohz.com/1-hp-single-phase-output-vfd

I am not much familiar with the subject. But, take liberty to give my penny worth as below:

I see electronic regulators come with ceiling fans in homes etc. Can one such thing not work for this application? If efficiency is not a criterion, even potentiometer type speed regulator can be an option.

Now-a-days, washing machine, AC, refrigerator all are inverter operated and single phase. How about finding one suitable VFD from stores which sell those parts, used or new?

https://en.wikipedia.org/wiki/Variomatic

All of the suggestions have their merit,and I certainly do appreciate the positive feedback.

However,this is an experimental model,and I am trying to use what I have on hand.

I have the motor and pulleys,and may go with an adjustable sheave.

Once I find the most efficient speed,I can size the proper pulley sizes for a fixed speed.

At that point,I will no longer need a variable speed drive.

I cannot give any details of the device because of possible future patent intentions.

But if I must name it without giving away it's intended purpose, let's see...HMMMM...HMMM....OK!Got IT!

How about Super-Dooper-Pooper-Scooper!?

It will be made by one of my subsidiary companies that also makes sports bra's:

UpperTopperFlopperStopper,Unltd.

OK,Enough of that.Seriously guys,thanks for the feedback!

Your button has malfunctioned, so I fixed it for ya'...

Thanks!

Take a look at the Allen Bradley Powerflex Low Voltage Drives Selection Guide, publication PFLEX-SG002M-EN-P July 2019. We have been using Powerflex drives for quite a few years from medium voltage (4160 vac) to 480 vac. They are a very good drive for any application. Ease of use, set up, and reliability. Low voltage 120 vac are also pretty cheap for your application.

Might I suggest a large diameter flat wheel like a flywheel from a car or truck etc. Mount the motor at right angles to the flywheel with a rubber wheel on the motor shaft resting on the flywheel.

You can then move the motor on a slide either in or out to vary the speed and also change the wheel diameter to get to the desired test speed that performs best. A motor mower wheel will do the trick and the flywheel will provide inertia to even out the revolutions and slippage.

Hi, I don't think a single-phase motor speed control is a good idea.

What would be a better idea is to invest in proper Vsd 120vac Input 120vac Output but 3 Phase

With a 3 phase motor running from a single-phase supply you will obtain far better control than you could ever get from a single-phase motor! Your trying to prototype you want reliable speed control for prototyping, also 3 phase motors are cheap

I am trying to use what I have on hand for this mock-up.

I understand the sticking point is the centrifugal switch and the start winding.

Going below the start switch RPM will kick in the start winding.

The switch can be adjusted,but I do not want to do this.

I thought about using a 3phase output VFD,but only using 2 phases to control speed,but this has it's own set of problems.

PSC motors will work very well with VFD'S, but my motor is a cap-start type, so I will probably use the adjustable pulley sheave .

Not as convenient,but is effective and simple to implement with the materials on hand.

The multi-step pulleys are a good idea,but I do not have the room for them.

In theory,all single phase motors are 3 phase motors that are single phasing.

I have only seen 1 110v 3 phase motor in over 50 years of experience,but have seen plenty of 48 v 3 phase motors in automated equipment.

These machine were very long and 3phase was used to improve efficiency and reduce wire size.

50% more power can be carried with the same amount of copper.

Anyway,back to my original topic,I have a 3phase motor that will have to be modified to fit.

It is a face-mount vs a base mount,which has it's own base already mounted.

If the adjustable pulleys do not provide sufficient turn down ratio I will have to fabricate a mount for the 3 phase motor and buy a VFD.

Thanks for the feedback everyone,and I will update as events transpire.

All of the VFD's I have seen, use single phase in, three phase out. You should be able to find a 1/2hp 3 phase motor for cheap. I have two Automation Direct 1/2hp VFD's that I would be willing to donate to the cause. Display allows RPM readout as well.

For a single phase induction motors with centrifugal or capacitor start, forget VFD to control speed. You will most likely burn up the starter winding if you get rpm low enough to engage the centrifugal starter switch. A variable sheave will likely give you the best results fastest.

Most capacitor start motors like on your ac system, well pump & pool pumps don’t have switches, the windings are sized to keep the capacitor connected. Not sure even wash machines use centrifugal switches any more. VFD will work fine, tho not needed in this case, as we find out.

If it temporary, use a variable speed drill to figure out to the speed you need. JHF

You might want to look for a used washing machine motor from a newer type machine. They should be had from salvage. In my experience, on modern machines, especially front loading , the first thing that fails is the drum spindle bearing. The cost to repair this is normally more then the cost of a new machine. Thus the machine is scrapped.

You will have to supply your own driver for this type of motor.