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talvare

Ted A
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Unless you can find the other leads and reconnect for 240 I'd suggest going with the VFD.
John & Izzy,

You could use a VFD but it would only power the spindle motor. The rest of the machine would have to be run from a different power source since there are several other motors and at least some if not all, are DC. Actually, I think the rest of the machine could be operated by supplying 230V single phase power to the primary side of the control transformer that's in the electrical control panel. Components like the magnetic starters could be eliminated (or just disconnected). That may be a good way to go. I'll have to think about that some more.

Ted
 

Izzy

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The feed motors would need to be powered separately even if I went with a transformer and vfd setup? so I would power the machine with 460 3phase just as it is I've been calling around and I found a used vfd/transformer set up for 600. But if there's anything cheaper and easier I'm in!
 

JimDawson

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The feed motors would need to be powered separately even if I went with a transformer and vfd setup?
The VFD/transformer is only for the spindle motor. The rest of the equipment all seems to be 120V. You could split that off ahead of the transformer, or just run another cord and plug it into the wall. That's what I do.
 

talvare

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Izzy,

I was just looking at the schematics that you e-mailed to me. What you could do is get a VFD with 230v single phase input and 460V three phase output rated to operate your 4 HP motor. Wire the 460V three phase output from the VFD to the tops of the three fuses designated as FU-2 in your panel (you would discard the existing wiring to and from those fuses). Then disconnect the three wires (T1,T2 & T3) from the bottom heater connections on the magnetic starter and connect them to the bottom side of the FU-2 fuses. This should put your VFD power directly to the spindle motor and utilize the existing fuses to protect the motor. Then you would disconnect the existing wires from the tops of the fuses designated as FU-3 and connect a 230V single phase power source to the top side of these fuses. Then you just need to re-do the primary side wiring on the control transformer and connect it for the 230V input as shown on the transformer. I think that should work. I'll give it some more thought to make sure I'm not overlooking something.

Ted
 

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What you could do is get a VFD with 230v single phase input and 460V three phase output rated to operate your 4 HP motor.
Have you got a link to a voltage doubling, 230V input VFD? Be a handy thing to have for some applications, but I have never seen one. I have seen (and used) 120V in, 230V out VFDs

Wire the 460V three phase output from the VFD to the tops of the three fuses designated as FU-2 in your panel (you would discard the existing wiring to and from those fuses). Then disconnect the three wires (T1,T2 & T3) from the bottom heater connections on the magnetic starter and connect them to the bottom side of the FU-2 fuses. This should put your VFD power directly to the spindle motor and utilize the existing fuses to protect the motor.
Normally you don't want anything but wire (or a choke) between the VFD and the motor. The VFD takes care of the motor overload protection.
 

talvare

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Have you got a link to a voltage doubling, 230V input VFD? Be a handy thing to have for some applications, but I have never seen one. I have seen (and used) 120V in, 230V out VFDs
No I haven't Jim. I guess I was assuming that since they make 120V in / 240V out that there would be a 230V in / 460V out. I guess not ?? So, I guess he's back to needing a step-up transformer if he stays with 460V.

Ted
 
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Izzy

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The VFD/transformer is only for the spindle motor. The rest of the equipment all seems to be 120V. You could split that off ahead of the transformer, or just run another cord and plug it into the wall. That's what I do.
ahh see I was under the impression that I just had to run 460volt 3phase power to it and it would all run the same because of the step down transformer it has for the feed motors I'm glad I've got some help tho I'd be upstream without a paddle!
 

JimDawson

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I did a little research and found it is possible to modify some 460V VFDs to make them 230 in 460 out but only up to about 3 hp without extensive modification for the higher HPs
 

JimDawson

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ahh see I was under the impression that I just had to run 460volt 3phase power to it and it would all run the same because of the step down transformer it has for the feed motors I'm glad I've got some help tho I'd be upstream without a paddle!
That's what is so great about this forum, we try to keep each other out of trouble. :)
 

Izzy

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Lol that video XD they did another one of those videos but with a transmission, kills me everytime XD.
If I went with an rpc instead of a VFD would I still need to re configure the control voltage?
If it ran on 460 3phase before why would I need to change things if it still has the original voltage? Just trying to understand how this all works
 

Ulma Doctor

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if it ran before on 460 volts 3 phase and you hooked it up to 460v 3 phase again, logic would tell you that it should run exactly as it is.
 

Izzy

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So just go ahead with a rpc and transformer? Cuz then it would all be same as before. If I'm understanding this correctly a vfd is just a motor controller where as a rpc just puts out 3 phase power correct?
 

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The RPC/transformer would work fine. An RPC outputs 3 phase but has no other control functionality.

Or so would the VFD. The VFD outputs 3 phase also and is a variable frequency motor controller which is kinda handy.

I would take your motor over to the motor shop and see what it would take for them to get it to run on 230V. I really don't think it needs a rewind to do that. And I'm pretty sure they can get that pulley off also.
 

Izzy

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I haven't had time to mess around with the motor but I should be able to get it off.
Going back to what Ted said about the vfd only powering the spindle motor why is that? Like wouldnt I just run the 3 phase wires out of the vfd to L1, L2, and L3 at the top of these fuses and be good to go? Doesn't the machine have a step down transformer that converts from 460vac-120vdc? I feel like I'm missing something and that's why I'm.not getting it :/
IMG_20161002_020452.jpg
 

JimDawson

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The reason is that the VFD output must be connected directly to the motor. No fuses, overloads, switches, etc. The VFD takes care of all of the safety stuff and switching. The VFD is not a 3 phase power source like a RPC, it is a 3 phase motor controller. It will convert single phase to 3 phase, but can only work correctly when connected to a motor, or maybe to the motor through a 3 phase transformer.

upload_2016-10-12_9-6-2.png
 
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talvare

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Going back to what Ted said about the vfd only powering the spindle motor why is that?
What Jim said plus, VFD's provide "variable" voltage and frequency. You don't want anything other than the proper "constant" voltage and frequency going to those electronic components as well as things like the coils on the mag starters, relays, etc.

Ted
 

Izzy

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Ok ok I think I understand, so since the vfd doesn't put out a consistent voltage and frequency it would mess with the rest of the electrical components as they need one constant voltage to work correct? So that means that I could just run 3 phase power from a rpc to those fuses in that picture then I wouldn't have to touch anything correct?
 

JimDawson

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Yup! ;) But you still need to deal with the 230-460 issue.
 

Izzy

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Ok I think I'm getting somewhere lol so would it work if I ran a roto phase to a 3phase step up transformer so then I'd have 3 phase 230 in and 3phase 460 out? Then just ran that to the L1, L2 and L3 terminals on the fuses?
 

talvare

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Ok I think I'm getting somewhere lol so would it work if I ran a roto phase to a 3phase step up transformer so then I'd have 3 phase 230 in and 3phase 460 out? Then just ran that to the L1, L2 and L3 terminals on the fuses?
Yes
 

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Yes.........But, by the time you buy a RCP and a 3 phase transformer you will have more $$$$$ into it than just getting the motor to run on 230, and buy a VFD.
 

Izzy

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Awesome! And if I went that route I wouldn't have to touch anything else just turn it on and make chips right? If I can't find the other 6 connections in the motor I'll probably go down that route as I've got a line on a rpc and transformer.
I know Ive been annoying with the simple questions and all but I appreciate y'all walkin me through this!
 

Izzy

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Izzy,

I was just looking at the schematics that you e-mailed to me. What you could do is get a VFD with 230v single phase input and 460V three phase output rated to operate your 4 HP motor. Wire the 460V three phase output from the VFD to the tops of the three fuses designated as FU-2 in your panel (you would discard the existing wiring to and from those fuses). Then disconnect the three wires (T1,T2 & T3) from the bottom heater connections on the magnetic starter and connect them to the bottom side of the FU-2 fuses. This should put your VFD power directly to the spindle motor and utilize the existing fuses to protect the motor. Then you would disconnect the existing wires from the tops of the fuses designated as FU-3 and connect a 230V single phase power source to the top side of these fuses. Then you just need to re-do the primary side wiring on the control transformer and connect it for the 230V input as shown on the transformer. I think that should work. I'll give it some more thought to make sure I'm not overlooking something.

Ted
that sounds easy enough hopefully I can find the other 6 wires so I can go down this route it seems cheaper and quicker as far as getting it running goes if I can't find the other 6 wires then a rpc and transformer will be my next option I was quoted 600 for the rpc and transformer together
 

JimDawson

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$600 is a pretty good price, so that is a good option.
 

Izzy

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Yea it's not too bad I'm still gonna try for the 230vac conversion if I can that seems like the cheapest and most reliable option but it's always good to have a back up right!?
 

John Hasler

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Ok ok I think I understand, so since the vfd doesn't put out a consistent voltage and frequency it would mess with the rest of the electrical components as they need one constant voltage to work correct? So that means that I could just run 3 phase power from a rpc to those fuses in that picture then I wouldn't have to touch anything correct?
You probably could configure the VFD to just act as a constant voltage, constant frequency three phase source (possibly with some additional components) but it would be a waste.
 

mksj

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So maybe a few thing to clarify.
  1. I am not aware of any VFDs that have 230VAC in (single or three phase) that will regenerate it to 460VAC. Above 3Hp, most VFD are 3 phase input, to use on 230VAC single phase you need to double the VFD rating. So in this case, something like a 7.5 or 10Hp VFD to run a 4Hp motor, pricey for a decent VFD. It is not recommended to use a VFD as a fixed frequency 3 phase output to a machine when there are other components systems other than a motor; i.e. transformers DC drives, etc. Most likely both will be damaged. There are fixed phase solid state converters, they are very expensive.
  2. Even if the machine was wired for 230 VAC and you did not have the motor issue (it can be rewired to 230VAC), you still could not run it off a VFD wired directly to the machine, the cost of a single phase in to 3 phase out in the 4-5 Hp, you would be looking at a similar cost of an RPC. At 3Hp and below a VFD for a single machine is more economical.
  3. If you where to use a VFD, it would be wired directly to the motor, and would be separate form the rest of the powered components. It can be done to just run the motor, but it makes a lot of the controls and load meter useless. So you are talking a lot of rewiring and new switches. Most of the machine drives and electronics operate off of 115VAC output from the large 2kVA transformer, the transformer could be wired for 230VAC and only is connected to L1 and L3 (so it is essentially single phase). So a total rewire and new controls.
  4. A VFD since it is a direct connect to the motor does not require output fusing, but should have input fusing. More wiring and costs, VFDs use high speed fuses which can be expensive, otherwise use a breaker
  5. A static converter is a band-aid, the spindle motor would lose about 1/2 of its rated Hp, the other components would not care because they essentially run off of single phase.
  6. If the machine is rewired for 230VAC running off a RPC, you still need to change the fusing and the motor thermal/current relays.
  7. A VFD in my view doesn't add anything in this picture, mostly because there are lots of subsystems, you do not need the speed control, or the other features one uses on VFD. I have built a number of VFD systems, and I am a proponent of them, but this is one situation where I do not think it is a good fit unless you redo the whole system.
So we are back to what is the easiest way to be plug and play (and probably the least expensive route unless the motor can easily be rewired). A RPC and then a step up transformer going to 460VAC, this is what I most commonly see if it is not a simple rewiring of the motor. Brain fart on the step down transformer and voltages when using it to back feed. So your voltage would drop a bit, but that is not an issue, given line voltages tend to be a bit higher these days it would be fine. These are very common on the used market. If you opt not to use a step up or back feed a step down transformer, next would be taking the motor to a shop and seeing if they can rewire it to 230VAC, this is not something obvious that you will find the wires and know how to reconfigure them. A motor shop can asses and hopefully bring the correct wires out in the proper fashion. Then change the fuses, wiring to the transformers and thermal relays. Once again, you need to be comfortable, and need to methodically trace the power in and makes sure it is rewired/fused correctly. If the fuses are on the output side (secondary) of a transformer, they would not be changed.

If you were quoted $600 for an RPC and step-up transformer for this size load, I would jump on that in a heartbeat.
 
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