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Bridgeport Romi 13-5 Lathe Issue

Can your transformer be powered by 120/240?


If it can.... don't power it from the VFD. Bad.

Motor straight to the VFD - But this requires you to run your fwd/rev/jog/e-stop controls to the VFD
If doable I’d rather up my transformer or get a transformer designed for VFD’s before I touch any of the factory controls. Only reason I went with VFD’s to power my equipment is due to space limitations, price, and two machines on different 3 phase power. Don’t have any desire to use any controls that are not on the machines.
 
It's not like lathes are really high duty cycle machines. Stick a fan on the transformer and call it a day.
Kinda what I thought as well. Had a parts company find me an exact replacement transformer. Was thinking about swapping them and putting a fan and closely monitoring. As mentioned before the current transformer was experiencing heat with prior owners from looking at the pre wiring pictures. So maybe a brand new one that didn’t come “pre-heated” will tell a different story?
 
then upstream of the VFD put a switch that supplies the 240 single directly into the transformer?
Absolutely. You could wire it into the input of the VFD if you’d like. Currently your transformer input is wired into the 1&2 (200V) taps. What is your actual input voltage? If much higher you might consider using taps 1&3 (230V). The following shows the two input leads to the transformer circled.
IMG_2364.jpeg
 
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Thank you, I will try moving the tap and see what happens.

Would a sinusoidal filter on the input of the VFD help anything? I know when looking at wiring the VFD’s they suggested those for noise. But would they also help with heat and helping out that sine wave? Or would it even matter because it’s before the VFD and would actually need to be installed after the VFD?

Again I appreciate everyone’s help and the explanations and reasonings. Way easier for a person to grasp a concept when it’s explained rather than just being told you can’t with no explanation.
 
Input filters are generally to stop noise from the vfd from feeding back into the grid and disturbing other equipment on the grid. I don’t think there’s anything there for you as it won’t change the output waveform of the vfd.
 
I have a KB VFD selected for being pretty basic, and had planned to use it on two machines, but a careful read through the manual and it’s not an option to run it as a “dumb” power source. The automated nature of all the functions that it constantly monitors and conditions it safeguards against, make configuring it specifically for each motor a requirement unless they are very close in size.

I‘ve only read through an installation manual for one other VFD, and it had much more strict requirements for setup, which is why I went with the KB, but now I can see how a wider variety of features is nice if it can be setup and left on one machine.

Your VFD will have its own limitations, and I don’t envy anyone having to sort out the details - makes my head hurt. It’s a good sign that you aren’t setting any error codes - that’s all I know. Good luck.
 
Through this whole thread, it seems the expected possible failure of the transformer is it will just quit, with no damage to any other component or the machine. Is that realistic? What else could happen if the transformer fails?
 
Through this whole thread, it seems the expected possible failure of the transformer is it will just quit, with no damage to any other component or the machine. Is that realistic? What else could happen if the transformer fails?
I suppose it could catch fire. My bet is if it failed one of the winding's will short from the heat (insulation breakdown) ultimately resulting in an open winding and that would be that. Might blow one of the fuses too if when it shorts. In my experience when a transformer winding fails nothing downstream fails. There's just no voltage to run the circuit anymore. What is sort of telling though is that some of the worst looking wires on some of the taps are not being used which suggests they are just being cooking due to heat coming off the laminated core. Maybe all he needs to prolong it's life is adding a previously suggested fan to cool it.
 
Through this whole thread, it seems the expected possible failure of the transformer is it will just quit, with no damage to any other component or the machine. Is that realistic? What else could happen if the transformer fails?
It looks like a dry transformer, so I doubt there would be much of a fire. I guess there is a chance that the transformer primary(input) shorts to the secondary but I have never seen it happen.
 
I have a KB VFD selected for being pretty basic, and had planned to use it on two machines, but a careful read through the manual and it’s not an option to run it as a “dumb” power source. The automated nature of all the functions that it constantly monitors and conditions it safeguards against, make configuring it specifically for each motor a requirement unless they are very close in size.

I‘ve only read through an installation manual for one other VFD, and it had much more strict requirements for setup, which is why I went with the KB, but now I can see how a wider variety of features is nice if it can be setup and left on one machine.

Your VFD will have its own limitations, and I don’t envy anyone having to sort out the details - makes my head hurt. It’s a good sign that you aren’t setting any error codes - that’s all I know. Good luck.
For sure, I haven’t been getting any error codes at all on either of my vfds. Have one set up to run my Bridgeport J head and one set up to run this lathe. Both are set with the exact parameters each machine is wanting and also have kills programmed in with the VFDs.

But yeah so far no issues have been occurring. Everything has been running fine. Only thing I noticed was the transformer in the lathe being a little hot for my liking after a day of work.
 
A new replacement transformer has been ordered and am in the process of ordering some fans/vents with dust proof filters to mount into the electrical cabinet of lathe.

Will update with what I find. Might swap taps and install fans and see what happens before I completely swap transformer.
 
A new replacement transformer has been ordered and am in the process of ordering some fans/vents with dust proof filters to mount into the electrical cabinet of lathe.

Will update with what I find. Might swap taps and install fans and see what happens before I completely swap transformer.
I'd check that ground connection on x4 as well.is that the schematic for your machine?
 
I'd check that ground connection on x4 as well.is that the schematic for your machine?
It is the schematic for my machine. It’s just showing a 230v model. My lathe is a 200v motor with the nameplate asking for 208v.
 
Once again, thank you everyone for the help and guidance with this issue. Believe it has been fixed with a simple fan blowing directly on the transformer.

Installed the fan a couple days ago and proceeded to work the lathe for 4-5 hours. Checked the transformer once finished and it had a much more comfortable heat. No trouble leaving your hand on it for however long I wanted.

I will keep running this transformer for the time being. But I have a new replacement transformer on the way that I will keep as a spare. Thanks again, Happy New Year!
 

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