600 Volts 20 Amps 3 Phase Needed

[will_eng]

I have a CNC Lathe requiring 600 Volts 20 Amps 3 Phase. I only have 240 Volts Single Phase in my shop. I know Phase converters are quite popular but can you run am transformer to step up voltage? It seems all i have seen is 240 to 240 or 240 to 480 but never 600 volts.

Reguards. W.G.

[Al_The_Man]

If you get a phase converter that will run a transformer it does not matter what the secondary voltage is, you can get 240 to 600v but the 600 to 240 are more common so you may have to run it 'backwards'.
if you do, most manufacturers advise that the output voltage will be less than nameplate due to the compensation factor of the windings.
But if it is a 600v and you get 575v output, this is often the voltage of the service in Canada.
If a rotary type of converter, you do not however get the added advantge of obtaining the false leg assistance from other three phase motors being fed by the converter itself.
Al.

[will_eng]

Thank you. This Fourm has been very helpfull. Has anyone here done this before? And I understand how this would work but would an electritian be comfortable with doing something like this(wiring up a phase converter and running a step down transformer backwards) or are these things common enough? Also is there a supplyer or a good secondhand source for Phase converters and transformers?
Reguards W.G.

[Al_The_Man]

I have used 600 to 240 single phase reverse connected for 600v to power a tap disintegrator and worked fine. The rotary type converters are fairly cheap and easy to build, there are some previous posts here where I have links to building one.
Surplus 240v 3ph 4 pole motors are usually easy to obtain.
Al.

[murphy625]

Not sure if this is any help but yes it can be done very easy..

I run a 15 hp rotary phase converter that outputs 240 3phase.. I run this into a 3phase transformer that boosts the voltage to 480.
Are you sure you need 600 volts??? I've never seen this..
What I have seen is 480 volt systems that use equipment rated at 600 volts. (most 480volt equipment is rated for 600volt service) its just a saftey thing and is done because canada operates at 575 volts @50hz.

Are you sure you require 600 volts??

[Al_The_Man]

Originally Posted by murphy625 its just a saftey thing and is done because canada operates at 575 volts @50hz. Are you sure you require 600 volts??

Canada Is 60hz BTW same as US.
Practically all transformers I have installed here are designed to operate at 600v wether Y or Delta. And will deliver 600v three phase on a 600v secondary.
Most do however have taps to allow for adjustments at least 25v up or down.
Al.

[murphy625]

Al!! Your in Canada!! I did not know that..

I went to a little town just umm(North) I think of Toronto to supervise the de-construction of a very large process system. (Large as in 40 semi trucks to move it)

The whole thing had 575 volt motors marked at 50hz.. We ran them for a good 6 months on 480 volts 60hz (here is the USA)and they rotated faster than the marked RPM's.
The system was a solid 15 years old.. (umm. that would make it about 23 years old now)
Has Canada changed?? Or am I missing something?

Thanks,

[Al_The_Man]

Originally Posted by murphy625 The whole thing had 575 volt motors marked at 50hz.. Has Canada changed?? Or am I missing something?

I don't know where those motors were meant for, AFAIK Canada has always been 60hz, I am not sure why the reason for going 600 though. I believe Australia is 50Hz but cannot remember whether they went with 440 same as UK.
Al.

[will_eng]

I talked with a guy at an Industrial electical place that has done phase converter stuff before. And he told me I needed a special phase converter and it would probably cost me $10,000.00 all wired up and done. Is this true? He mensioned something about me having like variable drives and that was why. But if me spindel motor is just a regular 3 phase motor with a transmition and i have a hydrolic unit and a few little pumps on 3 phase and wouldnt my whole control be DC (my servos are DC)? Or coudl i just get a regular phase converter to power the 3 phase motors and then get a rectifier to rectify singel phase 220 to __DC for my control? I dont know alot about electrical things but basicaly i want to know about cnc with phase converters. Reguards W.G.

[Al_The_Man]

I know a few people that are using rotary converters, some home built, for various CNC machines, especially if you have a regular induction motor for spindle, I am using one to run two mills that have VFD's on the spindle and single phase for the control and servo's.
I think that guy was spinning you a $10,000 line!!
Are your servo's 1ph? The only reservation I would say is if they are older 3ph SCR DC drives that fire directly across the line, If they are I would put a three phase line filter before the machine, manufacturers like Hammond make them.
Al.

[will_eng]

Ok I'm ready to start talking numbers and things I need to specifically do. I am in some what of a dilemma since people I talk to are very negative and then the people on here and other pages on the net are confident this can be done. So regardless I am striking out to see what I can learn and hopefully accomplish something instead of just talk. I understand a lot of you have small lathes and mills and things like that and I know the concept should still apply to a larger machine. I have attached a table with all the specs for my machine. As you can see I have like 15.5HP in motors. On the outside of the machine it says 600V 20 amps, which works out to 12000 watts which equals a little over 16HP. Maybe that has no relevance but regardless I’m looking at about 15-16HP.
It seems a lot of rotary phase converter success stories involve a 1HP lathe or something of that nature. http://home.att.net/~waterfront-wood...econverter.htm This sight tells a bit about calculating capacitors and building a phase converter. Its example is also a 1HP motor and just says to scale up for a bigger motor. But is this a linear scale? Can you just scale up with no problems? I know it said you would have to play around with caps wand what not but even still.

So for my 16HP I need Cap L1-L3 =80uf and Cap L2-L3=200uf?

http://www.phaseconverterinfo.com/ph...verter_cnc.htm

This sight has a lot of interesting stuff on it too.

The widely variable load of CNC machines exposes the primary weakness of rotary phase converters, namely, the inability to main balanced voltage. A rotary phase converter can provide balanced voltage at only one load point and the more variable the load, the worse the voltage balance. If a CNC machine is operated on a rotary phase converter, the converter must be oversized to minimize the voltage imbalance. Oversizing the phase converter to improve voltage balance will result in poor efficiency, often as low as 70%.

Any thoughts or ideas on what to do as far as sizing for my specific machine?

[Al_The_Man]

Is this the 600v m/c? If so what is 600v on the machine, even the aux motors in the list, Hyd, lube coolant etc show as 220v. The spindle drives and servo's are more than likely 220. If so it may be possible to study the prints for the possibillity to run of 220/240, although you would need around a 12 - 15 hp converter but would not need the 600v txfr.
You would also have the advantage of the 3 phase motors assisting the converter process.
The oddball frequency shown on some are strange? they should be all 60hz.
The spindle and the servo's go into electronic drives, which in most cases on Fanuc are 220v 3ph.
Al.