Thanks Danilo,

Appreciate the links and info. His says 400hz (the one I purchased) but from looking at the other identical spindles, they all say 300hz, so i think they just copied the 3kw page. What I'm wondering is if they can be run 380v @ 10amps, because I can supply that voltage and it would be cheaper to run for me. I did set it for 230v 10amp and it seemed kind of soft sounding in comparison to the one I listened to on a video.

It seems that all the spindles in this class (4kw) are 4 bearing, German or Japanese adopted, and all of them can run either in 230v or 380v mode. Some of the sellers charge more for 380v, and more for 4 bearing, or more for german, etc... But they are all the same. But I could be wrong... My VFD will set for 230v or 380v so not sure what to do and don't think I'd find out from a Chinese seller without actually risking burning up my spindle myself. The only other thing I could think of would be star vs delta in wiring the coil, but that is only because the ABB VFD guy said something about that.

Anyways, I'll see what happens if I up the voltage.
Thanks,
Chris

Alright, you've got me confused about the spindles. I guess I'll have to try hunting one down myself to fully appreciate what's been said... or I can wait a bit and find out what happens...(saga continues)

Chris, you should run the spindle at the manufacturers recommended voltage. That is what it is wound for. That being said you can run a motor at a lower or higher frequency but the lower the frequency the hotter your VFD will get especially if you start it at a low preset and low it down. Most of the 400Hz rated motors can be run at 100 Hz but I would not go lower as you are well below at third of the rated Hz. The insulation of the motor windings allows the frequency to be moved up and down and resist thermal breakdown. There is a lot more to it than even what I have here.

Thanks Pete, I've been trying to figure out what to write here.

1) Lower limit is 100Hz = 6,000 RPM to avoid undue heating and failure.
2) Upper limit is based on the rating / quality of the bearings, not the electronics. Typically this will be 300hz = 18,000 RPM, or 400hz = 24,000 RPM.
3) The nameplate amperage limit is generally a hard limit based on the size of the wire used in the winding. Exceed it and the wires will heat and self destruct.
4) The voltage limit is a function of the insulation, the designed wattage and thermal characteristics, and magnetic characteristics. It is a little fungible, and theoretically your manufacturer knows best - if they are putting their best foot forward.
5a) A "classic" 3 phase inductance motor has a characteristic rotation speed, limits its current draw by the resistance of its wiring, and thus has to be supplied a specific voltage to limit the current draw and keep the heating under control when running at the design speed. If you run this motor on a VFD and reduce the speed, you risk overheating; if you increase the speed, you risk the bearings.
5b) Spindles, which are designed exclusively to be run with VFDs are a little different than a classic inductance motor; they expect an electronic control to limit the current, and thus the winding isn't necessarily designed to be self limiting. Wire it up directly to a 50 or 60hz supply, and it will run slow (at 3,000 or 3,600 rpm) while consuming more current than it can handle, and will overheat, melt, short, and fail. Quickly. However, if driven by an intelligent controller that regulates the current, they don't care as much about the voltage, because the windings were never designed to be limited by voltage in the first place.

HOWEVER ...

It's hypothetically possible to run a single manufacturing line that produces identical spindles of a given HP/KW that can be stamped at the end to be 230v or 380v and 300hz or 400hz without any actual differences. They will run, and perhaps even run well in lightly loaded circumstances, but not have the lifetime you might want. Are the bearings really rated to 24k? Will the windings really withstand a fully loaded bit at 6k RPM at 230v for a full days cutting? Does the insulation handle the DC spikes that far exceed the AC input?

At $3k per spindle you should care, at $300 per spindle you should keep spares.

Hopefully this reduces the confusion, and doesn't increase it. Chris, at the end of the day, I'm with Pete - when you step outside the manufacturer's rating, you're on your own to validate all the assumptions. Be careful and report back if you go down this road, please.

I'll try to do this as plainly & my command in English allows...
The spindle basically is an Induction Motor, works using the electromagnetic principle that Rotor's magnetic field "chasing after" stator magnetic field. the AC current generates a running magnetic field which rotates along the stator coils in a fix direction & the speed of that rotation depends on the AC waveform frequency (which is the job for the VFD), so higher the frequency, faster the the magnetic field rotates. This stator magnectic field induce another magnetic field in the rotor which always want to align itself with the stator magnetic field, hence, the rotor "chasing after" the stator magnetic field...

The current rating is identical at across the 1~400Hz in theory, in fact, at higher frequency skin effect will effectively improve the reliability, but that is in the range of thousands Hz, 400Hz really isn't gonna improve much. so our usual wall frequency is 50/60Hz, hence using conventional calculation serves enough safe factor in the calculation.

The torque equation is identical too. which is
W(rad/sec) x Torque(N.M) = Power(Watt),
BUT there is always a but in real world, due to all sort of inefficiency, 1~25Hz isn't reliable, anything above is nice & dandy.
With water cooled spindle, the spindle temperature remains constant because it has better cooling then the air cooled spindle which the fan is designed to work best at very high rpm.
As you can see, from the equation, the Torque is inversely proportional to the speed, as long as te power is constant. but in real life the motor only draw enough power for the rotor to "catch up" with the stator. & this power limit is the rated spindle power which the coils are designed to handle...

The only real limitation is the bearing rpm rating, not the coil wire size &/or coil turn.

AS for the voltage. the VFD output voltage is select-able, & this must matches the spindle motor voltage & as far as I know, Chinese Spindle are rated at 220V 3 phase.
u can choose whatever VFD input voltage you wish or limited to... As long as you don't overload your house circuit & burn down the house.

I hope this will clear up the voodoo & snake oil on VFD & spindle.

Brad and Ken, Excellent tutorials! Very good info, Thanks.

Thank you guys for the time spent in clarifying this. It's really helped a lot and wow, such fantastic and detailed information I could not have gotten anywhere else, THANK YOU!. I'm going to run it 380v 9amps.

The seller got back to me and said that it is indeed a 400hz motor, and that it can run on the 380v VFD. At 230v he said that it is rated at 12amps but I think they derate it to make sure it will last a bit without burning up. I suppose if I run it at 9 amps 380v it should be ok, especially if I keep it under 300hz. My VFD of course can run 230v too, but with higher voltage I'll save a lot in electricity since I do have 3 phase

I've purchased on ebay a tiny thermistor and I'm wondering if I can place it on the inside of the extrusion somewhere to monitor temperature.

Thank again guys for the help.
Chris

Setting Volts and Amps is related to risk of overheating and melting insulation or copper.
Setting Hertz is related to speed and risk of a short bearing life

When a supplier of a cheap spindle tells you that it is rated for 400Hz, take that with a big pinch of salt. Sure, it might do 400Hz for 2 weeks under light load. The cost of high speed bearings from reputable companies is more than the typical prices of the cheap spindles.

We are in the murky territory of DUTY RATING . . . . . how hard, how fast and how often will you use the device sold by the vendor? When it doesn't come up to expectation, he will say you drove it too hard, or too fast or too long, or something similar.

"and that it can run on the 380v VFD"

380 VFD and 380V motor is two different things, this sentence means that the VFD is rated for 3 phase 380V input.

"At 230v he said that it is rated at 12amps"
This is the value I should start using it

300 - 400 Hz is only the maximum RPM , 18.000 - 24.000
using the spindle for 3 years I never had a need for the speeds above 18.000 or 300Hz
but the rpm rating is for bearings so with a 24k rpm motor used at 18k rpm you are not pushing it too hard as 18k at 18k rpm.
I recently changed bearings in mine, they were indeed high speed P4 precision labeled and looked ok for the price of the spindle.

Thank you for that. What I've noticed is that some of the 4kw combo VFD with spindle sales say that they do have a 380V VFD in stock. I'm curious, if i'm running my VFD with 3ph 380v input, but setting it to 3ph 230v output 12amp, is it pretty much the same as if I set it to output 380v in terms of current consumption on the input side? Not sure if it would make any difference setting it to 380v output in terms of current consumption anyways.

I see what you mean Danilo, the 380v VFD can be set to output 230v anyways, and maybe that is what he means. What do you set your spindle output for in terms of amperage and voltage?

The motor is rated for 220v or 230v, your OUTPUT of the VFD MUST match that, If you are able to supply the VFD with 380V then do that. As far as the line supply is concerned it only "sees" the input to the VFD, it will make very little difference what the output is set to as it completely changes the current passing through it (voltage and frequency).

Mine is a watercooled 2.2kw 220V set at 9Amps as that is the info etched on the spindle body

Chris, I don't want to add confusion to this already but there is a lot to motors that is not even covered here. First, how is your power supplied there, Wye or Delta? Things can be different based on the country we are from. Mostly here in the US power is supplied in WYE. If you want a motor with a constant torque, you would by an inverter rated delta motor with a specified torque ratio and use it with the VFD and the VFD being specified as a Vector Type. However, most three phase motors here are a split voltage 230/460 with the Wye motors supplied with 9 wire and the DELTA with 12 wire. These Chinese spindles are supplied with a dedicated wiring for 220V and only three wire connection. Some come with 4 or 5 pin connectors and some come with and without a case ground connection in the connector. Again this is where the confusion can and will start. With little known about how the spindle is wired internally. Now with this all to confuse you, with your VFD you specify the HP or kW of the motor and FLA. The FLA will tell the VFD to never exceed the amperage you tell it. I have never seen a VFD that you supplied a high voltage on the Line side and it supplied a lower Load voltage. (Not saying there isn't one but I don't know how the v/f relationship would work then as they usually both vary) Typically you use a transformer to reduce the voltage before feeding the the Line side of the VFD with required voltage, in this case 220V. On your concern of saving money, I have never drawn the maximum amperage of 9A that my spindle is rated at or even close to it.

I even set my VFD to 8Amp for my 3Kw spindle. I still cut harder than when I was using a 2.2Kw spindle with the lower amp setting.

Thanks guys, Pete I don't know how it works but my VFD, the ABB acs350-03u-15a6-4 is able to set 230v even with 380v input. Also it has vector type speed control, but I am not sure what that means. I did try it, but my spindle didn't run with that.

I'll set it to 12 amps as he's told me to, but I have a suspicion that it will run fine at 15amps. I think they under rate the spindle so that they don't burn out.

Unfortunately for me, my spindle didn't come with a sticker plate, or a manual, so there is nothing to say what it is supposed to run at. I really would love to change the 2 bottom bearings to ceramic, but have no idea what sort they are, and would have to disassemble in order to find out. Bearing pullers on ebay are cheap, and I have a friend with a hydraulic press so it wouldn't be too much of a nightmare I don't think.

Ok, well it runs fine on 230v 10amp, I'll up it to 230v 12 amp and run with it like that.

Regarding mounting of the spindle, was I supposed to drill and CS the 6 holes for mounting from the back of the Z plate and the rest from the front?

Glad you have it working

Rack finished, any boring advice for pinions?
 

Thanks Pete,

Rack is welded, drilled, taped, and mounted. Looking at the pinions, searching the forum about boring them out and not too thrilled about having to get them machined. Has anyone gone and bored them out themselves on a press with good results or should I just bite the bullet and get them bored? They are 10mm now, need to get them to 12.5mm.

The cost of 4 hardened pinions from OZ, with shipping, was 1/4 the cost of buying the same quality pinions, though non-hardened here in NZ.

Will post pics of the rack mounted soon but all went well. That tape is so strong!

Thanks!
Chris

If you drill them on a drill press with 12.5mm drill it might produce a bit larger hole.

try on some scrap metal and see if it is a slip fit. otherwise get them machined

Thanks Danilo, Do you think that if I use .5mm increments it would stay concentric?

Here are what my pinions look like.

http://s9.postimg.org/4yaz97lvf/IMG_2237.jpg http://s9.postimg.org/dhyykpjln/IMG_2238.jpg

It all depends on your desired end product. Remember once you start giving a little in one area the next thing you know you are giving a little in another and it affects everything exponentially. If pretty close to straight, I do not think it would affect your run too much. There is a little leeway in the design. The rack is mounted with double sided tape and the spring allow for a movement when running. Forged angle is not perfect. As long as you have a true vise to your drill press chuck, you could drill it open. Boring on a lathe would be your best option, that is what I would choose.

If you do not have a rigid mill or lathe to ream them out, I would find a small shop locally to do it for you. If you do it your self, only do one at time.

You will need a reamer bit to finish the hole and I would use snub bits (real short) to drill the holes because they are more ridged. Also make sure your table is as close to the quil as possible.

I would farm this out, or at least be ready to order another. I think I recall someone here trying to do this without much luck.

Issue is not about being concentric (which is also an issue) but you could drill a hole a little bit too large and when you put setscrews the pinion could wobble.
so drill on a lathe and ream the hole as metalhead said is the best option

They make adjustable reams. We use them a lot when repairing machinery. That is another option. http://www.mscdirect.com/browse/?nav...rs&hdrsrh=true

I don't remember anyone on this site boring out pinions successfully on a drill press. A few have tried. SurfCNC for one.

Why not drill your pinion on a milling machine with a strong mechine vice & lovely V-blocks. Drill bench are meant for lesser precise jobs.

Thanks for the advice guys. I luckily just had a friend of the family going to school taking a turning class, who has access to a CNC lathe. He just took all 4 pinions and is going to try to get them done tomorrow. Fingers crossed.

On another note, I've mounted all the Drag chain and ended up with some leftover. Just an FYI, I used one section of 2meter, one of 1800mm, took about half meter off the 1800 and added it to the 2 meter for the x axis. Chai has good chain that is 75mm bend radius so it worked out well.

I've just received my 8 channel relay board that operates off 5v logic so I'm going to use that to turn on vacuum, Dust Collector, laser, plus 3 indicator lights, and so forth on my second parallel port off the smooth stepper. I really love all this stuff and how it meshes with Mach3.

I've been interested in seeing how far I could get with running LinuxCNC on a raspberry Pi board. It sound really interesting if not for this project then maybe for another. Also been looking for quadrature encoders for the OM steppers I have but so far haven't found anything below $50.

Cheers,
Chris

I forgot to add, my spindle mounting hole pattern is spaced in 1.5in intervals. So I guess I must drill entirely separate holes as they run into the other ones on the plate. Thank goodness to betsy that I didn't drill into a real guage plate yet.

It Moves!
 

Job Well Done Chris!

Congrats ... Looks great!

Thanks still have a bit to do. Sensors, wiring up the push button boxes, and painting it. But it all works so far. Inspiring!

Full speed
 

Loving this machine! Here are another couple vids showing full speed rapids. Man, im surprised how fast it runs!:D Allie, my helper iis running the machine. Made some progress on estop boxes and routing.

http://vimeo.com/69613423
http://vimeo.com/69617216

http://s04.flagcounter.com/count/zVf...ews_1/flags_1/

That's looking really good, you will soon have that cutting, keep up the good work
Andrew

Thanks Andrew! I'd be cutting today if I had 3 phase in my build garage. Maybe I need a backup spindle and VFD that is single phase just in case.

Your cable chains are too short?

I tried to tighten the swag by shortening them... but they make the run. suppose i could add a few more links. the x one ??

The x one is very unhappy at the end of travel. Only saw that at end of video and didn't go through vid again to check Y. Sag is a totally normal event for drag chains - nothing days we have to get them parallel.

Gerald's eyes are amazing at times. I didn't even pick up on that.

Sag is only on some chains and every manufacturer is different. Most IGUS chains will not sag but some of their cheaper ones will. Your X/B chain should have another 2 to 3 links. That and with a solid no rotation 90° end connecter will help with some of the sag. You should have the half circle with the chain at the each end of travel else you will be flexing your cables at a tighter bend radius than the rest of the chain. That will be where you wires will break first. Another thing that is not that big of an expense is to chain the Y complete to the end where the X/B chain is. It is not needed but gives a much nicer look to the machine. HTH

Thanks, will do it as I have 7 or 8 more links. Does that mean I have to redo the chain holder on the Y axis if I add more to it?

Cheers,
Christ

All depends if it is an open top chain if you mean the end anchor for the chain. If you mean the chain supports, you can add more supports easily and tie together if you wish.