Mill is 3-phase 440v, I have 1-phase 220v - What kind of options do I have?

I have a 10 hp RPC and it runs to 3phase breaker box then to disconnects for all the machines prolly over kill but I like it.

I can run 4 of my machines at the same time if-n I could run fast enough to keep them form doing bad things,

If I would have went the VDF route I would have needed 8 so it was cheaper to do it the way I did.

Paul
 
Thanks guys. I think the VFD option is most likely "out" as I understand it you can only run one motor per VFD. While that would take care of the two main motors (I don't think you would have an occasion to run both at once but what do I know?) but the rest of the power system may be an issue (power feeds, DRO).

Even if the motors can be re-wired for 220v 3-phase I would still be in essentially the same predicament, needing something to convert my single phase into 3 phase, or worse as I don't know how the power feeds and DRO are powered. Now that I think about it, a lot may depend on how both the DRO and feeds are powered and if they are easily repairable. From the description I've got on the mill the x-axis feed has gone bye-bye and there is "something" wrong with the DRO box, whatever that amounts to.



Judging from this pic, everything is powered off the side of the mill. Do power feeds generally use something more "conventional" in the way of power? So if there is some kind of conversion going on in this power layout wouldn't that all have to be reconfigured, if possible?

Can someone give me a little more insight as to if this is a reasonable assumption?

I see on the web that "Sargon" is now out of business but there equipment is being supported by Linear Measuring Systems whether that will make any difference. I see that the old DRO appears to be set up for X and Y, on a mill, is there a huge advantage to adding a Z?

Thanks,

-Ron
 
The power box on the side looks like it may have 110 out. I would not be surprised if the main motor is dual voltage as stated before and you can drive that easy with a 220 VFD with your current 220 single phase. The other motors may likely be single phase and therefore only 220 volt or 110 if that picture is actually showing a 110 plug. On our shop the machines that have smaller motors for pumps etc are powered by 1 leg of the 3 ph supply.
You will know more once it is at your door but a motor shop can help you out after that.
I have a lathe with a 220 single phase 1 1/2 hp. I talked to the motor guy in my town and he will set me up with a 220 v 3ph motor, used but with warranty, and a VFD to run it with 220 1ph power. Cost he says about 200.
 
That sure would simplify things a bit as well as get it up and running for a more reasonable amount. That would be money I could put in to some tooling! :biggrin:

I'll be keeping my fingers crossed,

Thanks,

-Ron
 
Ron

Here is the link to my electrical setup. I had a similar situation, except that I needed 600V

To get 440V 3 phase substitute the transformer to a 440V one and use the appropriate load centre to distribute the machines. If only using for one machine you can run from the transformer directly to the machine without the load centre as long as the transformer is fused (or breaker) properly between the RPC and the transformer.

Also note that there needs to be a Timing Line Contactor, TLC between the RPC and the transformer to prevent the transformer from ever being single phased. If you look closely at my diagram you will notice that I have my complete system going through a TLC, which saves having to wire interconnects between the mag switches and the RPC for each machine and makes sure that I never single phase a three phase motor.

http://www.hobby-machinist.com/show...seMAXX-7TZ-Soft-Start-RPC?highlight=phasemaxx

Walter
 
Now that I have the mill home I had a chance to look at the motors and I found that they can be wired for 230v 3-phase (they are 460v 3-phase now) so maybe that will simplify the process in that I only have to turn single phase 220v in to 3-phase 230v. It also looks as if the power feeds and the DRO all run off the regular 110v.

Even though it has two motors I don't believe there would ever be a situation in which they should both be powered on at the same time. Now, the only odd thing is that the vertical head is 2 HP while the horizontal is 3 HP. If I am to go with a VFD which is only good for 2/3 the rated HP (I believe), that would mean I need a 5 HP VFD. Does that sound right?

-Ron
 
I would think in your case a RPC would be your best bet, it allows you more options for future machines that may be 3 phase. If you go VFD you'll have to buy more of them for each machine.
 
Ron

In the past, VFD's had to be derated if you wanted to hook them to single phase input instead of the 3 phase input they were designed to run on. Nowadays, you can get a 3 HP 1 Ph 230V input VFD that has 3 Ph 230V output and has already been derated by the manufacturer.

5 Hp VFD's are still on the spendy side, or at least good ones are.

If you can swing the RPC, would be the best option as allows all sort of expansion later.

Otherwise a 3 HP 1 Ph input VFD would run either motor, but you would have to set up a plug, switch or relay set up so that only one could run at any time and that the power would have to be off to the motor in order to switch between them. Applying open circuit voltage from a VFD with no motor load will allow the magic smoke to escape, so the wires must go straight from the VFD output to the motor input with no switches, fuses etc between them.

Walter






Now that I have the mill home I had a chance to look at the motors and I found that they can be wired for 230v 3-phase (they are 460v 3-phase now) so maybe that will simplify the process in that I only have to turn single phase 220v in to 3-phase 230v. It also looks as if the power feeds and the DRO all run off the regular 110v.

Even though it has two motors I don't believe there would ever be a situation in which they should both be powered on at the same time. Now, the only odd thing is that the vertical head is 2 HP while the horizontal is 3 HP. If I am to go with a VFD which is only good for 2/3 the rated HP (I believe), that would mean I need a 5 HP VFD. Does that sound right?

-Ron
 
I would think in your case a RPC would be your best bet, it allows you more options for future machines that may be 3 phase. If you go VFD you'll have to buy more of them for each machine.

Otherwise a 3 HP 1 Ph input VFD would run either motor, but you would have to set up a plug, switch or relay set up so that only one could run at any time and that the power would have to be off to the motor in order to switch between them. Applying open circuit voltage from a VFD with no motor load will allow the magic smoke to escape, so the wires must go straight from the VFD output to the motor input with no switches, fuses etc between them.

Walter


Okay, I can take a hint. ;) I'll plan on the RPC as I'd hate to have the magic smoke escape. :p :lmao: As I have had a chance to ponder what you've both said, I think you guys are especially right, as expanded upon by Walter with the switches etc. This unit only has one plug for the two motors so all the switching between the two takes place "internally". While doable it would just make it more complicated to try and run with a single VFD. I'd most likely need to take the switching external so I could use one VFD for both (not an optimal solution), run two VFDs (added expense and external wiring) or just go with the RPC and keep the magic smoke safe.

I'll certainly have more questions as I get down to deciding on a particular setup.

Thanks guys,

-Ron
 
The mill has landed! Now I have a question about the RPCs and which route would be better. The way I see it, going with an RPC, I have two choices. The first being to get an (5 HP?) RPC that will take single phase 220v and output 3-phase 460v. The other option would be to go from single phase 220v to 3-phase 230v and rewire both motors to handle 230v.

Is there really any difference between the two options other than the hassle of rewiring the motors? I also like to protect what I have the best that I can so where would Walter's suggestion of "a Timing Line Contactor, TLC between the RPC and the transformer" fit in to this?

Thanks,

-Ron
 
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