Need Help!- KM3 Phase Converter?

[centuryz]

Hi All,
I have a KM3 that is running very well under normal 3 phase conditions. I am about to move this machine to my home shop where 3 phase is not available. Like many posting I see here and around the net, a phase converter will get the job done if properly sized and configured. I have a static converter but now understand thier limitations.

I see that a Rotary would be better but heres my questions...
Reading through my schematics, I can see that only 3 motors are 3 phase on this machine, the spindle, coolant flood motor and spindle speed override motor. I can easily live without the coolant flood for the work I do (with mist only) but the speed override may be an issue.

Any thoughts of solutions other than a variable speed drive (inverter)? If I hook up a static phase converter properly sized (considering only these 3 motors are affected) will it all work? L2 and L3 are feeding the transformers so I trust the controls will all be fine.

My real concern is whether the speed control override will work (maybe slower) or not at all? Also, am I just way off track to use this static unit even though the control transformers are connected to the true 220 lines.

Thanks for any support so that I can feel more confident on hooking it all up.

Mike
San Diego, CA

[Captdave]

My vote would be for the rotary converter for several reasons. As cheap as they are (pick up a panel of Fleebay and add a used motor) it makes sense to have the power available for all the mills options. If you ever add any other equipment to your home shop you'll have power available for it as well.

I started out with one small CNC several years ago and now I have 3 plus all the support equipment are 3 phase. Had to upgrade on HP but never short on power.

[skullworks]

So centuryz - Is your machine a KM3 or a KM3P

If it is a KM3 then your Vari-drive is operator set via the hand crank. The KM3P has the speed motor - and a different table/saddle.

I have a KM3P running on a 10HP RotoPhase and while that is all well and good - economically its killing us.

Being on rural power grid the cost per KW/hr is nearly 3x what it costs residential customers in town. So just having the phase converter running, the Hurco "on" but in E-stop so there is no servo power - the cost quickly mounts just to be able to program the machine at the console.

I can swap out the 3ph coolant pump - I know Enco has a 110V perfect replacement which I have fitted to other machines in the past. Likewise perhaps a static converter would be enough for the speed control motor? ( I honestly don't know its load requirements) Then fit a Standard VFD to provide 60Hz 3ph to the OEM motor.

And here is where we go off the paper....

I have seen update kits put out by other machine tool builders which swap out the vari-drive pulleys for a fixed tooth ratio drive and fit a replacement inverter duty motor with matched VFD. Now the only "manual" speed adjustment is to shift into back gear when you really need it.

The $64,000 dollar question is - Is there a way for the Ultimax (Max32 in my case) software to drive the VFD and maybe even adjust the min/max usable spindle speeds. - Another possible but far less likely option would be the ability to rigid tap if an encoder were fitted.

[centuryz]

Thanks guys for the thoughts...

I do have the KM3P. Sorry for the typo. I have the spindle override switch near the quill to adjust the RPM electro/mechanically. I have thought alot about it today and think that if I hook it up on a static 3-5hp converter, it will work at 50~75% spindle rating but I will not be able to use the spindle speed override. Just my reasonable assumption. I dont mind the coolant pump not working and I like your idea of just getting a 115V replacement.

Since I have the 3hp spindle motor and the spindle speed is ultimately adjusted mechanically not electrically through an inverter, I think (if I have read the net correctly) that a rotary converter is the best. What do you think? Rotary would also allow me to run the speed control override and the coolant pump right?

I understand one main difference between rotary and static is that rotary runs the 3rd phase live constantly where the static is only on for a few seconds at motor startup. My brains numb on that whole point! :-)

Thanks for any input...

Mike

[skullworks]

The motor type phase converters are far superior to statics, and can run several different machines at the same time as long as the machines don't start at the same time.

[centuryz]

Great, thats good to know. I am looking at the Rotary style today and will likely pick one up. Seems like the best solution. Thanks for all the help guys!

Mike

[Rich Carlstedt]

I have a KM3 with Ultimax II
I run it on single phase 240 V
First thing to realize is that the Controls and Servo drives only need single phase !
So I wired the transformers to receive their source from the Two power leads ( which I will call A & B) (fused of course after the main disconnect)

At first, I had a 5 HP Rotary Convertor That fed the two motor ( Spindle and Coolant ) Relays, but I did not like the noise or the excess wasted current.

So I bought a 5 HP Invertor (Mitsu*****i VFD 3 phase to 3 phase) and used it for my 3 HP Spindle. ( You can use 3 / 3 units as 1/ 3 , if you only use 65% of power)
I changed the coolant pump system to 110 Volt

I added a new relay(Motor contactor), so when I turn on Servo power , it also closes the heavy contacts that provide single phase power to the VFD, using the same feeds ( A & B but fused ) as the transformers get.
Removing all input wires and output wires from the original main motor contactors allows me to use those contacts for the VFD (single poles on/off) for off/on/for/rev.
I also added a Manual over-ride , so I can do MDI work by bypassing "control" statis.
I can jog the spindle or use it for edge finding when doing manual axis moves.
It all works beautifully
Here is a photo of the over-ride box I have posted on photobucket

http://i273.photobucket.com/albums/j...s/P9010004.jpg

Stay away from statics ( although coolant should be OK)
I would buy a VFD for spindle " speed" drive for under 50 bucks
In fact, here is a 1/4 HP GE for 31 dollars
http://www.dealerselectric.com/

Hope it helps
Rich
I can post a schematic perhaps ?

[centuryz]

Hi Rich,

Thats great info thanks. I couldnt see the photo but the information was very helpful. I have considered the VFD's but havent switched just yet. It works so well for me just as it is.

I have wired both main transformers to the L2 and L3 which is the clean existing single phase. I purchased a very nice quality 5hp rotary converter. I am planning to wire the wild 3rd phase leg to the L1 clear of the electronics. My schematics and my physical inspection appears to support this course. I hope Im right! :-)

I have 3 motors that require 3 phase... spindle, coolant pump and spindle speed override.

My real concern is in hoping the prints are correct and that the L1 is clear of all electronics and that my tracing didnt miss anything.

Thanks for all your great help!

Mike

[bloke]

If you just want to program at the the control, you could always put a two-gang toggle switch just before the power supply in the machine cabinet and use it to switch between the machine's 115v supply and a wall socket thus cutting out the need to run the whole machine.

[skullworks]

Originally Posted by bloke If you just want to program at the the control, you could always put a two-gang toggle switch just before the power supply in the machine cabinet and use it to switch between the machine's 115v supply and a wall socket thus cutting out the need to run the whole machine.

I like the idea, but will the machine diagnostics let you get to the point where you could do part programing? As is now it wouldn't let me get past square 1 if the shop air pressure is too low.

[Rich Carlstedt]

Mike
The Schematics are very accurate from my experience.
Sorry the photo didn't work.
I tried putting the URL up several times and I had problems.
It worked for me just now ?
Your wiring sounds OK

I like Blokes comment about 115 Volt to run the control only.
Great idea. Are the Fans on 115 or 230 ?
I may do that as I sit for hours sometimes writting programs.
I do not have a CAD/CAM setup nor do I use G code
I bypassed my air switch and installed a electric solenoid for braking where the cylinder was ,
Saves air, as I don't need my compressor running and I can also manually turn on the brake at anytime
Thanks Bloke

Reminds me , When I got my Hurco, The Previous owner who had it new and for 11 years said he never had a service call and the electrics were all original. I liked that as the Bridgeports I have seen all needed Board work after 3 years
I bought it (10 years ago), because of that as I am not an electronics guy, but I have and can do industrial power wiring.
Well I Smelled the power transformer and could see some residue starting to leak ??
So I added a wisper fan to the Transformer when ever 230 v power comes on.
Works geat and the smell went away.. Check yours for heat !

[centuryz]

Thanks Rich and Bloke,

I like Bloke's idea too. Nice one.

Got the machine home tonight and the new Rotary Phase Converter. I should have it all in tomorrow.

I agree Rich that the schematics look correct. For some reason, someone has moved one wire to L1. I am putting it back to meet the schematic so that both transformers are on L2 and L3.

Thanks again!

Mike