Thread: Running this three phase fan from one phase 240VAC

I've acquired this 3 phase fan and would like to use it to ventilate my shed by varying the speed. I don't know if it works but it is undamaged and the three windings all give about 60 ohms resistance so I presume it will. It is wired in delta configuration.
Single phase 240VAC is readily available in my shed (but not 3 phase) so I figure a VFD would work. Maybe a device such as this... 0.75kw/1HP 240V Single Phase Variable Frequency Compact Drive Inverter VSD VFD (cononmotor.com.au)

Would this VFD suffice or are there better options?

Here's some photos....
fan1.jpgfan2.jpgfan3.jpg

Hi Harry, Welcome to the forums.

A cheap VFD would work just fine, but you will need to be careful to watch for over heating if you reduce the supply frequency too much ! The same applies when increasing the frequency. Here the greater fan speed will work in your favour due to the increased air flow.

Oh, some more info....
Just spoke with a VFD supplier and it to choose the correct VFD it seems I need to know whether the fan will accept 240VAC 3 phase or whether it only accepts 400VAC 3 phase. It is not 100% clear from the nameplate.
Any idea how I determine this?

Originally Posted by harry wall

I've acquired this 3 phase fan and would like to use it to ventilate my shed by varying the speed. I don't know if it works but it is undamaged and the three windings all give about 60 ohms resistance so I presume it will. It is wired in delta configuration.

It's not possible to determine whether its ∆ or Y sed on the resistance alone. Even if it is ∆, it could be 415V ∆, if so it cannot be converted to 240 ∆.


It doesn't matter whether its ∆ or Y what matters is that it is 240V ∆, or 240 Y


Chances are it will be 415V Y.
Whether it is ∆ or Y, it will still run safely on 240V, but it may not reach full speed and if/when it does it will draw more current than usual and overheat the motor. Running it at more than 50Hz is likely to also draw even more current. If you decide to keep it running I would monitor the motor tempertir carefully.


Ehatever VFD you get you will need one on which the max current parameter is able to be set. Not all budget level VFDs do this.

To be sure it work without any changes buy a 240V SP input 415V 3P output VFD - search for Ecogoo.
Costs a bit more but you wont need to change a thing.

Thanks Bobl.
I'm guessing the fan is only 400V (415V) because nothing else is mentioned on the nameplate. Another diagram under the terminal cover shows it is definitely delta wired.

Other examples of motor nameplates I've seen show two sets of figures: one for 240V and the other for 400V but I have no experience in this area to be able to say with authority that the absence of a second set of figures means it must only be 400V. Seems logical to conclude that however.

Something like this may be worth the gamble... 0.75kw/1HP 415V Three Phase Variable Frequency Compact Drive Inverter VSD VFD (cononmotor.com.au)
Oooops, no it won't. I just noticed it needs 415V input. Can't see anything from Conon that has 240V input and 415V output. Back to the research.....

I've seen mention of the ecogoo products (no Australian suppliers that I can see) but I'm happy to pay an Australian supplier like Conon for a similar product.

Hi Bob, Harry,

Oops I missed the voltage rating on the nameplate ! I'll consider my wrist slapped for that...

Originally Posted by harry wall

Thanks Bobl.
I'm guessing the fan is only 400V (415V) because nothing else is mentioned on the nameplate. Another diagram under the terminal cover shows it is definitely delta wired.

Other examples of motor nameplates I've seen show two sets of figures: one for 240V and the other for 400V but I have no experience in this area to be able to say with authority that the absence of a second set of figures means it must only be 400V. Seems logical to conclude that however.

Something like this may be worth the gamble... 0.75kw/1HP 415V Three Phase Variable Frequency Compact Drive Inverter VSD VFD (cononmotor.com.au)
Oooops, no it won't. I just noticed it needs 415V input. Can't see anything from Conon that has 240V input and 415V output. Back to the research.....

I've seen mention of the ecogoo products (no Australian suppliers that I can see) but I'm happy to pay an Australian supplier like Conon for a similar product.

Sorry no known Aus suppliers of 240V SP input to 415V 3P output

I've not yet found an Australian supplier so I may have to try Aliexpress and this product...

VFD 0.75KW/1.5KW/2.2KW/4kw inverter AC Frequency Inverter 1 phase input 220V and 3 phase 380 V output|Motor Driver| - AliExpress

I couldn't find any reference or links to the user manual for this product. Did I miss it somewhere? If no decent user manual then I won't bother buying it.

Does anyone have any comments on: (a) whether this would suit my needs, (b) tips for using Aliexpress since I'll be a first time user ?

Harry, I have sent a PM. I have a PFD of the user manual. Steve

Originally Posted by harry wall

I've not yet found an Australian supplier so I may have to try Aliexpress and this product...

VFD 0.75KW/1.5KW/2.2KW/4kw inverter AC Frequency Inverter 1 phase input 220V and 3 phase 380 V output|Motor Driver| - AliExpress

I couldn't find any reference or links to the user manual for this product. Did I miss it somewhere? If no decent user manual then I won't bother buying it.

Does anyone have any comments on: (a) whether this would suit my needs, (b) tips for using Aliexpress since I'll be a first time user ?

That should work just fine.
Alie Express is good...its just some of the suppliers that use the platform who may not be...so dont forget to ensure your parcel does arrive, and should it not just lodge a complaint...you will get your money back..in my opinion just as good as ebay, amazon etc

Do you want to vary the speed?

If not, you can run a 3 phase motor from a single phase supply. I've seen it done.
We used to do that on our feed water regulator actuators at work. They need to be reliable and they were. I don't know it was done that way........

Not particularly efficient buts its cheap to do.

You only use any 2 of the windings, plus a capacitator.

Hi Harry, Guys,

Using capacitors to provide a second and third motor phases works very well ! Its only a small low powered fan motor, and if you are not bothered about controlling its speed capacitors are a good solution.

Have a look at these links !

https://www.electricneutron.com/elec...-power-supply/

https://electronics.stackexchange.co...ta-connection/

Originally Posted by Reidy41

Harry, I have sent a PM. I have a PFD of the user manual. Steve

Thanks Steve but maybe there is a library somewhere in this forum that you could place it. Then others can benefit by accessing it.
I cannot locate it right now so maybe I'm mistaken.

Hang on Harry.
If the fan is wired for 415V Delta, then it will not be able to be wired for 240V. That is unusual for a smallish motor. The wiring image indeed shows delta connection....
So the EcoGoo VFD taking single phase 220/240V and outputting 380/415V 3-phase seems your only simple option.
Running a fan on the wrong lower voltage is not a good idea, because the load (the fan blades) is fixed for a design speed. Running it slower with lower power may make it overheat because of the magnetic lag, not reaching design speed at 50 Hz. Running it at design voltage but at lower or higher frequency will not cause that magnetic slip, thus less likely to overheat.

An update for anyone else considering running a 3 phase fan from one phase.
I used a 20uF run capacitor across one of the windings, connected 240VAC active (live) to another winding, connected 240VAC neutral to the last winding and the earth/ground to earth/ground.
A power meter was plugged into the 240VAC socket and the fan wiring plugged into the power meter. I ran it for 10 minutes seeing a consistent power consumption of around 380W and current draw of 1.6A. Given the nameplate power consumption was 400W I think it all looks fine. The motor, after the 10 minute run, was only just a tiny bit warm to the touch.
It was also very quiet considering the amount of air it moved so I'm content with not needing a variable speed.
Thanks to all for the comments.