thinking about how to power this mill

so, after wanting a milling machine for a few years, I broke down and bought
one - this one
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be specific. I've mailed $$ to the manufacturer in Sweeden who will send
me the manual (cheap, 55 euros), so now while I'm waiting for delivery, I'm
turning my attention to the next problem - how to power it.
You will notice that it says it's 440V - I don't know if the motors, etc are
dual voltage or not, but my garage doesn't have 440 in it. Of course I can
use a transformer and a bunch of VFDs or a rotary phase converter, or ....
but I wonder what the group experience might be. I can also rewind the
motor for 220 and use an off the shelf VFD, or I can modify a 440V VFD so it
accepts a DC input and then make a DC power supply (e.g. full wave doubler)
to supply it from the 220, or .......
so, what do you think?
Reply to
william_b_noble
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I think that 5 HP is not terribly too much. You can get yourself a 1:2 transformer and make a 440V rotary phase converter.
see
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His feedback is not great though.
I can check with Dave at Pioneer Industrial, he has some big xfmrs. He could part with them cheaply, but they may be too big for you.
i
Reply to
Ignoramus1487
You'll never get away with this. The doubler will make all your lights and other electrical gear go crazy, and may even cause the transformer on the pole to pop its breaker. This is a 5 Hp motor! The transformer scheme is a LOT better idea. Step down transformers are quite easy to come by. It may only have 2 motors - one for the spindle and one for the power feed. The power feed motors might also be small split-phase capacitor-run motors, ie. single phase, and maybe even running off a small 440 - 220 transformer. It depends on whether the power feeds are mechanically clutched or electrical.
Rewinding the motor(s) is going to be more expensive, unless you have a friend in the motor business. The standard power in Europe, I believe, is 415 V. So, if this machine is 440 V, it may indeed have dual-voltage motors, special for the US market.
Jon
Reply to
Jon Elson
It'll be dual voltage. I had to change the Abene I have over from 440 to 220 when my former employer bought it. The only problem is that it's not exactly user friendly to change over. I had the manuals for the machine but the wiring didn't match the manual completely (and not everything is covered in the manual). I ended up having to trace the wires around the machine for a while before I completely understood it.
There will be two motors that need the wiring changed (the main motor for the mill head, and the feed motor inside the column). Then you'll need to change the control transformer for the contactors. You might also have to change the coolant pump but I'm not sure there because mine had a replacement pump when we got it.
The wiring for the main motor is behind the round cover on the back of the milling arm (took me a while to find that one). The rest is inside the box on the side of the column.
BTW congratulations on the mill. I think you'll like it. I was pretty tempted by that one myself. In some ways it's in better shape than mine is.
Wayne Cook Shamrock, TX
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Reply to
Wayne Cook
I've tried both. I found that connecting a 3ph transformer to a RPC caused the transformer to heat up quickly. I actually burned one out. I imagine that part of the problem was the fact that the RPC was't balanced with caps as well as it should have been.
I have had more luck with using a single phase transformer to boost the voltage up the voltage needed by the VFD and feeding a VFD designed for 3ph input with single phase (but at approximately the right voltage). This is simply a matter of connecting the two single phase conductors to two of the three line in terminals on the VFD. The VFD should be derated, but in a milling application I don't see it being terribly important as the starting load is low and the machine if used by a hobbiest is gernerally not pushed too hard.
Since large single phase transformers are hard to come by, I am experimenting with using 3ph transformers to boost the single phase input. In a week or so I will get a used VFD I bought on ebay hooked up to such a transformer so that I can try it out and let you know how it goes.
stan
Reply to
stanley baer
Not a good idea on his mill since there's two motors in it and one of them can be turned on and off while the spindle motor is turning. In fact the feed motor is reversed when rapid traverse is engaged.
Wayne Cook Shamrock, TX
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Reply to
Wayne Cook
SNIP------------
Thanks Wayne - good input - I am currently under the impression that there are 3 motors (spindle, traverse, and coolant), and I probably won't use coolant. On my lathe, I used a VFD and just removed ALL the pre-existing wiring and contactors, etc and let the VFD to the start/stop/reverse work - that worked out nicely. I don't really trust rotary converters because of the need to balance them electrically, and furthermore they take up space (which is something I don't have), so a solid state approach is much more attractive. I've thought of driving a 3 phase transformer with a primitive VFD (well, a solid state single to three phase converter), but I don't know what the reflected transformer loads would be back on the device. So, if I can convert to 220V, that will be quite helpful. It still leaves the trick of deciding whether to rewire and exploit the new solid state controls or not.
by the way, Rolf at Abene says that the machine was made in 1970. I'm a bit farther away from it than you, since I'm on the left coast - I expect it to show up any week now, as I frantically move stuff around to try and ensure I have a place to put it.
Reply to
don't use this address to reac
experimenting with new news readers (outlook express has bogged down and takes forever to get messages, Free Agent seems fast, but I don't like the buttons) - anyway, messed up my identity, so this messge below really did come from me.
Reply to
William B Noble (don't reply t
Hmm. Well first off you'll need to check the coolant pump. It may or may not be 3 phase. I can't imagine not using coolant of some form on a milling machine. I've never used it on a lathe but it's pretty much essential in milling from my experience.
The way I see it you may end up needing two VFD's to make this thing run properly. At least you will if you want to even think about using the rapid traverse feature (and I'm not to sure about how well that'll work off a VFD since it uses the sudden reversing of the motor to shift into rapids). I suppose you could leave the feed motor on at all times (there's really no reason to turn it off, mine has not been turned off on purpose ever). However that will add up to a pretty good sized load for a VFD. I don't remember what HP the feed motor is but the main spindle motor is big enough that you'll want a 5HP VFD and higher HP VFD's which will take single phase input are harder to find.
Another point is the fact that the main motor is a special built motor and would not be easy to replace. On the other hand the feed motor is pretty much a normal motor and could be replaced if needed.
Interesting. I wonder when mine was made. There's enough differences between the two in minor details which makes me believe that mine might be slightly newer than yours.
Wayne Cook Shamrock, TX
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Reply to
Wayne Cook
Stan, the reason your transformer burned up when you had a VFD in front of it is the transformer is made for relatively clean sinusoidal power. The VFDs put out very "dirty" (sometimes actually square wave) power. The harmonics created by this dirty power cause losses within the transformer that it is not designed to take. You should always use a VFD after your final transformer, and not before, if you're going to use one. Mr. Noble, if you're intending to stay with the original motor, I would recommend a 220 VAC 3 phase slave motor of 15 HP driving a 3 phase transformer stepping the 220 VAC up to 440 VAC. Then, if you still want a variable speed drive, put it on the 440 side. The 15 HP motor will need to be started/run by a static phase converter. There's a lot of info on this out on the net, and if you need more information, I can find some good people in Indianapolis who can help further. Good luck with your new machine.
Reply to
Jim Reed
thanks guys - sounds like there is no brilliant secret, although I'm still not convinced that there isn't some way that doesn't involve moving parts to geerate 440AC 3 phase from 220 single phase - but I'm going to wait until I get the machine and then see what it really has in it - if I can get it to run on 220, then VFDs are the obvious answer - small ones are cheap, and for this application I don't need the fancy vector drives. I wonder if a 220/440 motor can be both a transformer and a phase converter at the same time - there's something to think about
Reply to
William B Noble (don't reply t
You could use a 220/440 rotary converter as a transformer, but it is REAL inefficient. The 220/440 motors use the windings in a series or parallel configuration to make the voltage/current change so none of the wires have to be large enough to carry a current twice as large as the HP rating requires. This means you would have to have a idler motor rated twice of what you normally need to power the same load - i.e. 7.5 HP idler for a 5 HP load becomes a 15 HP idler for the same load. Starting becomes tricky (now a 20X current inrush or greater rather than a 10X inrush), and the starting cap requirements grow exponentially (expensive). There are a couple of other concerns with this technique, but I think you get the idea. It's not the easiest, cheapest, or quickest technique. I don't know of any motors which are specifically made as rotary converters and step up converters at the same time, but if they were available you would probably want to consider that as a way to go.
"William B Noble (don't reply to this address)" wrote in message news: snipped-for-privacy@4ax.com...
Reply to
Jim Reed
I have the manual now, ordered it from Abene in Sweeden - they were very helpful, and it only cost 55 euros.
According to the schematic, all 3 motors are 3 phase, but there is no hint of any kind whether they are single voltage or multiple voltage motors - once the mill arrives, I'll be able to figure out the answer. Low power VFDs are really cheap, so I'm not worried about the small motors if they can run on 220, it's just making the spindle motor run that may be a bit of a challenge if it requires only 440. we shall see. The "good news" in the schematic is that it shows the control transformer with taps for 220, 440, and 550 - so at least the controls will work on 220.....
Reply to
william_b_noble
As I said before there schematic is less than helpful in the voltage change issue.
First off there's a round plate on the rear of the milling arm (near the crank for moving the arm if it's in the down position). Take this plate off and you'll find the wires for the main motor. I'll probably have to go out and take my plate off in order to tell you how to change them (it's been 6-7 years since I changed mine over).
The feed motor is both easier and harder. It's easier because it says on the motor how to wire it up. It's harder because it's buried up inside the main column and is nearly impossible to get to.
The coolant pump is easy to get to on the back and will probably state on it's plate if it's a dual voltage motor (likely) and may well state what is needed to change it on the tag.
(please excuse any typos, my keyboard is getting cranky, looks like I'm going to have to replace it after only 3 months use).
Wayne Cook Shamrock, TX
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Reply to
Wayne Cook
this Abene mill finally arrived - a long story. The good news is that it's wired for 220, so I won't need to worry about a transformer or other means to convert to 440 - everything seems to be dual voltage. My plan, unless someone here has a much better idea is to use two VFDs, one for the spindle motor, one for the ways motor, and to use a suitably sized capacitor for the coolant pump - a little motor that doesn't seem worth a VFD of its own. I like the VFD approach because of the soft start. If anyone has a better suggestion, chime in.... I don't really want to use a rotary converter because of space considerations
Bill
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will iam_ b_ No ble at msn daught com
Reply to
William B Noble (don't reply t
The only possible problem could be the feed motor. To engage rapid traverse the feed motor is reversed quickly (as in instantly). The VFD might not change it quick enough to make the rapids engage (you'll have to try it to see). I know that my mill is rather difficult to get the rapids to engage when it's cold with the instant reverse and it may take several tries before it does engage.
Wayne Cook Shamrock, TX
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Reply to
Wayne Cook
some more follow up info - the pump on this mill is .15 amps at 220 - no need for fancy circuitry there, though we shall see - the motor that moves the ways is 5.9 amps, (2 hp) the spindle motor is 6 hp, so, any thoughts?
Bill
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Reply to
William B Noble (don't reply t
I've now got this unit running using a simple (two relays and a capacitor) static inverter - you were half right - the feed motor reverses to actuate the rapid feed - it doesn't have to do it quickly, though it's convenient if it does - I have no trouble with it changing direction instantly, though I'm not sure I uderstand why it works. I built the static converter using some scrap parts I had lying around (two 250 UF starting caps, a small starting relay and a 110AC single pole relay)
now to find all the oil ports and fill it with oil.
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to contact me, do not reply to this message, instead correct this address and use it
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Reply to
William B Noble (don't reply t

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