VFD Question

[Bib Overalls]

Is there such a thing as a VFD for single phase 110/220V input to single phase 110/220V output?

I have a 1hp single phase motor on a drill press that I would like to convert to variable speed. Is it doable?

A search on eBay gave me a thousand plus "hits." All that I checked were for three phase motors.

If someone has this set up, a VFD for a 1hp single phase motor can you tell me the model and vendor you used?

I am dirt dumb when it comes to this sort of thing and at age 75 I don't have enough time left to get up to speed. Any and all help sincerely appreciated.

 

[slodat]

A VFD powers a three phase motor, only.

 

[Bib Overalls]

Thanks Steve. I was hoping I could get out of the belt flipping mode on my drill press but that is apparently not going to happen. Steve

 

[Bert_]

Single phase has a start switch and capacitors to help it start. Those things don't play nice with speed control.

Used 3 phase motors that size are dirt cheap. Just swap it out.

 

[930dreamer]

X2 on swapping out to a 3 phase motor for variable speed. If you go this route let me know and I might be able to find a new surplus motor at work. The 1hp vfd I bought was about $175 shipped.

 

[Bib Overalls]

X2 on swapping out to a 3 phase motor for variable speed. If you go this route let me know and I might be able to find a new surplus motor at work. The 1hp vfd I bought was about $175 shipped.

Many thanks for the offer. I may take you up on it. I have a millwright friend who spends most of his time swapping out equipment in hospitals and factories. It is amazing what they scrap out. Hoping he will come across a motor that will work for me.

I just put up a post asking, from a user satisfaction, what is the best motor for a variable speed control, AC or DC. If you have an opinion I'd like to know. I am particularly concerned about torque/power at low RPMs.

 

[ddawg16]

A VFD powers a three phase motor, only.

Single phase has a start switch and capacitors to help it start. Those things don't play nice with speed control.

Used 3 phase motors that size are dirt cheap. Just swap it out.

X2 on swapping out to a 3 phase motor for variable speed. If you go this route let me know and I might be able to find a new surplus motor at work. The 1hp vfd I bought was about $175 shipped.

Hmmmm....guys.....not accurate....done all the time. How do you think fan speed controllers work for ceiling fans?

The issue is the cost benefit. It's hard to justify the cost of a VFD on a single phase motor given the limited HP.

Here is one of many sources.........

https://www.invertekdrives.com/variable-frequency-drives/optidrive-e2-single-phase/

 

[Bert_]

Hmmmm....guys.....not accurate....done all the time. How do you think fan speed controllers work for ceiling fans?

The issue is the cost benefit. It's hard to justify the cost of a VFD on a single phase motor given the limited HP.

Here is one of many sources.........

https://www.invertekdrives.com/variable-frequency-drives/optidrive-e2-single-phase/

Some fractional HP single phase motors can be speed controlled. They are shaded pole and permanent split capacitor motors. Neither has much startup torque and a speed control really only controls the torque. Fan speed controllers are NOT a VFD, it's usually a triac or a series of capacitors that can limit the current to the motor. They do not change the frequency.

That works fine for fans or other constant torque loads, not useful for a drill press. A drill press motor would be split phase or capacitor start. You cannot vary the speed of these types of motors.

 

[wyliesdiesels]

Hmmmm....guys.....not accurate....done all the time. How do you think fan speed controllers work for ceiling fans?

The issue is the cost benefit. It's hard to justify the cost of a VFD on a single phase motor given the limited HP.

Here is one of many sources.........

https://www.invertekdrives.com/variable-frequency-drives/optidrive-e2-single-phase/

ahem, a fan speed controller is different than a variable frequency drive so previous comments are accurate

 

[ddawg16]

ahem, a fan speed controller is different than a variable frequency drive so previous comments are accurate

Yes and no.....one is a lot simpler and less flexible than the other.

Fan speed controllers are just simple choppers using and SCR (or Thyrisister). Works fine for fractional HP motors. But can cause noise.

VFD's convert the AC coming in to DC....then regenerate the output as needed. They still use SCR's or Thyristers.

The big advantage of a VFD over a fan speed controller is the ability to provide a lot more current torque at low speeds.

 

[rsanter]

Install a used 3phase motor, it a nice upgrade.
Or do the common treadmill motor conversion

To make a good variable speed conversion you need 3 phase or DC

 

[slodat]

Hmmmm....guys.....not accurate....done all the time. How do you think fan speed controllers work for ceiling fans?



The issue is the cost benefit. It's hard to justify the cost of a VFD on a single phase motor given the limited HP.



Here is one of many sources.........



https://www.invertekdrives.com/variable-frequency-drives/optidrive-e2-single-phase/

Yes and no.....one is a lot simpler and less flexible than the other.



Fan speed controllers are just simple choppers using and SCR (or Thyrisister). Works fine for fractional HP motors. But can cause noise.



VFD's convert the AC coming in to DC....then regenerate the output as needed. They still use SCR's or Thyristers.



The big advantage of a VFD over a fan speed controller is the ability to provide a lot more current torque at low speeds.

Huh?

 

[laser3kw]

VFD's convert the AC coming in to DC....then regenerate the output as needed. They still use SCR's or Thyristers

(actually they are IGBT's)
thyristor's latch "on" until current drops to zero, not desirable in hi freq switching

 

[ddawg16]

(actually they are IGBT's)
thyristor's latch "on" until current drops to zero, not desirable in hi freq switching

I tried to keep it simple....most guys know what an SCR or thyristor is....

One thing I do know....when they say "Discharge the capacitor bank before servicing".....they mean DISCHARGE it....ouch

 

[theoldwizard1]

Is there such a thing as a VFD for single phase 110/220V input to single phase 110/220V output?

I have a 1hp single phase motor on a drill press that I would like to convert to variable speed. Is it doable?

A VFD powers a three phase motor, only.

If you want anything more than fractional (< 1/2 ?) HP, VFD and 3 phase are by far the "best bang for the buck). In commercial HVAC, where 3 phase is available it is used on even "small" fan motors. I have seen 3 phase squirrel cage fans of about 1/2 hp for electronics cooling.

 

[ddawg16]

FYI....you can get a single phase to 3-phase VFD

 

[Phantomd]

ddawg is correct. Find a single phase input vfd. Easy to adjust speed and direction as long as it's not a big motor.

Here is a 110 v input model for a 1/2 hp motor. if you step up to 230v inputs you can go up to a 3 or so HP.
https://www.automationdirect.com/ad...ol/gs1_drive_units_(120_-z-_230_vac)/gs1-10p5

 

[Bert_]

Most vfd's can accept single phase, it's more common than not in my experience.

You can run much more than 3hp on a vfd with single phase input. I've done a bunch of 30hp motors and a couple 40hp motors with a vfd on single phase input.

 

[Augus7us]

Well played sir.