three phase coolant pump

[powderblast]

Hi i have just bought a lathe which is running on three phase i have bought a vfd to run the lathe from single phase

but i have a coolant pump that runs on three phase i have converted it to run on single phase but it appears to have a dip when running do any of you guys know what i need to do.

here the video clip

 

[powderblast]

heres a pic of the motor plate on the suds pump

 

[westward10]

So the lathe runs from the vfd but the pump does not, correct. How exactly have you "converted" it to run from single phase?

 

[Rocboni]

Looks like he's connected a capacitor across the terminals to create a phantom 3rd phase , usually the motor must be connected in delta but that doesn't look like a dual voltage motor so I would say that's the problem the motor will be running a lot slower than it usually does. Winding street must be intarnaly connected in star configuration as only 3 leads visible.

 

[westward10]

Didn't see the capacitor!
Well it will run but the efficiency and power will be reduced as the shift and/or phase voltage balance will never be correct by doing that.

 

[Rocboni]

You can get away with it with a small dual voltage motor connected in delta, giving 230 to each winding, but that motor will only be getting 115- 120v per winding connected in star.

 

[westward10]

He needs a single phase motor on it.

 

[powderblast]

So the lathe runs from the vfd but the pump does not, correct. How exactly have you "converted" it to run from single phase?

Hi i bought this and this runs great just got it working only down side is you loose all the original controls on the lathe but it all run on three phase and my house is only single.

putting a single phase motor on it would not of work because the electrics was all wire up for three phase

 

[powderblast]

You can get away with it with a small dual voltage motor connected in delta, giving 230 to each winding, but that motor will only be getting 115- 120v per winding connected in star.

Yes the pump is star only so i was told wiring it like this would only give me half the power which should be fine but my concern was the way it was running or is this common doing this will it run like this or just burn out??

i thought it may be dipping in power because of the capacitor no big enough???
im not sure i have never done this before just going of advice and forums.

 

[Rocboni]

2.5 is a bit small, usually thy are about 40uf

 

[westward10]

I think 2.5 is about correct for a 40w motor as you can base it roughly on 70uf per kw.

 

[powderblast]

what would be causing it to have a voltage dip if you listen to the video i have uploaded you will hear it

 

[Rocboni]

Looking at other forums that seems correct, not sure if using say a 3uf would improve things. You could try and find the star point of the windings and separate to you can connect in delta, things would be a lot smoother.

 

[powderblast]

Looking at other forums that seems correct, not sure if using say a 3uf would improve things. You could try and find the star point of the windings and separate to you can connect in delta, things would be a lot smoother.

i dont think you can change to delta maybe if you strip the full motor down maybe????

 

[Rocboni]

Yes you would have to strip it down to find the star point, it would have been made with 3 sets of windings so there will be a star point, it could be there as soon as you take the top off. Just depends how able you are, you could then reconfigure internally and bring out the 3 leads as it is just now.

It seems to be pumping sufficiently anyway, you'll never need that kind of flow for coolent on the lathe, it'll empty before it's drained back. You'll use it once and it'll be everywhere, I hardly use my collect pump, only if it's stainless steel I'm turning.

 

[powderblast]

Yes you would have to strip it down to find the star point, it would have been made with 3 sets of windings so there will be a star point, it could be there as soon as you take the top off. Just depends how able you are, you could then reconfigure internally and bring out the 3 leads as it is just now.

It seems to be pumping sufficiently anyway, you'll never need that kind of flow for coolent on the lathe, it'll empty before it's drained back. You'll use it once and it'll be everywhere, I hardly use my collect pump, only if it's stainless steel I'm turning.

its was they surging it was doing im concerned about the flow is ample i think you will have to turn it down

 

[westward10]

Can't you wire a supply from the lathe.

 

[westward10]

Why do you think it is star and not delta connected.

 

[Rocboni]

Never considered it to have 400v windings connected in delta, wouldn't that be unusual for such a small motor?

 

[westward10]

Don't know to be honest.