Changing from a router to a spindle.

[rockaukum]

Hello,
I am looking into changing from a router to a spindle. Some questions for you all if ya don't mind...
Looking at a 2.2kw with vfd air cooled. First question is what kind of cable is required between the vfd and spindle? Any suggestions for locating this cable?
I have read about only connecting three leads to the spindle and not the ground. yet I don't fully understand why some do and some don't.
What is the recommended lowest spindle speed for an air cooled spindle to prevent overheat damage?
Any other advice would be great as well!
Thanks in advance...
Rockaukum

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[ger21]

VFD cable. You can get it from McMaster-Carr, or from Igus.

People don't connect a ground, because they are lazy. It's potentially very dangerous to not do so.

I've heard that 8000 is the lowest safe speed. But it depends on the ambient temperature, and how hard you're pushing the spindle.

[plcamp]

Gerry, will a air cooled spindle still give the down blast of cooling air like a router motor?

And yes I agree with you 100%, an non grounded spindle motor can be lethal.

[ger21]

Yes, they blow air down, but not nearly as much as a router. The "fan in an air cooled spindle (with shaft driven fan) is more like an impeller (sp?), whereas a router actually has a fan. The impelller in the spindle does not move as much air. So it's still much, much quieter than a router. At 8000rpm, I can barely feel the air blowing through it, but at 24,000, it blows quite a bit, but still far less than a router.

[rockaukum]

Thanks for the reply guys! However this leads me to another question based on the "potentially very dangerous not to do so" comment...
I purchased this machine and it was loaded with "issues" and that is probably why it was sold. (told it was in perfect working condition, but the owner "never took the time to learn it").
Being new to this fun world and have learned a lot but feel very exposed with what I don't know, where can I go to find out about the grounding issue? I am unaware of any grounding done with this machine. I can give any information you may need in order to ensure "safe" operation.
time to start a new search today.... "proper grounding..."
Thanks,
Rockaukum

[ger21]

Without knowing anything about your machine, it's hard to say, but most stepper driven machines aren't likely to kill you if they aren't grounded. If it's all metal, a simple wire back to the ground wire of the main power is all you need.
The spindle, on the other hand, is high voltage. If you happen to get a short in the spindle, the body can potentially be live, and touching it could kill you.
The plug for the spindle should have 4 terminals. You need to connect the ground terminal to the metal body somewhere.

[rockaukum]

Cool. So if the machine seems to be working as is, and I add a Spindle, I connect the fourth wire to the ground terminal on the spindle and the other end to the metal table not the vfd? I am in no way a electrical engineer and struggle with wrapping my head around some of this stuff. However I am determined and really enjoy making things work. This machine was built in Southern California by a company called "lightening CNC". It is a metal tabel, gantry ect.. It was loaded with issues when I got it (second owner, I believe) and I have managed to get it somewhat reliable by way of this site and others. For that, many thanks!
Rockaukum

[ger21]

No. The VFD cable should have 3 wires + a ground. All 4 are connected to the VFD. At the spindle end, you need to add a wire to the ground terminal, inside the spindle, and connect it to the spindle body.So that when you plug in the spindle, it's grounded to the VFD. Which itself is grounded to your Main power ground.

[rockaukum]

ger21,
Thanks for the information and the quick replies to my inquiries.
I think I got what you are saying now. Big learning curve going on here... Once I receive the spindle and vfd, I'll open it up and figure out how to make this connection! Thanks much for the insight and safety points!
Rockaukum

[CNCMAN172]

The VFD cable should have three wires for all three phases + a ground wire, and it should have a braided shield just below the rubber outer layer. The spindle needs the body grounded with ground wire if the connector on the spindle only has three lugs. The braided shield also needs to connect to the spindle body, some connectors on spindles are all plastic so make sure the braided shield actually is conductive to the spindle body. On the VFD end the ground needs to attach to the ground lug and the braided shield also needs to attach to the ground lug. On incoming power the ground must be there as well, not just the 220V ac legs.

Russ

[Ryadia]

The spindle, on the other hand, is high voltage. If you happen to get a short in the spindle, the body can potentially be live, and touching it could kill you.
The plug for the spindle should have 4 terminals. You need to connect the ground terminal to the metal body somewhere.

Sorry to butt in on this thread but... My 1.5kw spindle is 10 volt max. Hardly high voltage. in fact the only high voltage thing on my router is the input to the power supply.

Using an air cooled spindle is going to seriously limit the time you can run your machine for. Almost all Chinese Spindles over 800kw are water cooled. It can take as long a 4 hours (or more) to create a masterpiece. Increase the spindle speed (read operating heat) by 20% and you reduce that time by almost an hour. It is seriously bad practice BTW to start a big job and walk away from the machine. Common sense would dictate you do it as fast as possible.

I know Zero about US power supplies and a big heap about electrocutions. I've had 2 of 240 volts in my lifetime and I'm still here to tell the story. If you have 2 pins on your wall socket – as many movies show for USA, its not earthed. For an earth to be effective a rod needs to be driven into the ground at least 4 feet down. In Australia it is illegal to attempt any sort of wiring if you don't have a license for it. That's because 240 volts is a fatal dose. I believe 110 volts is not but I still wouldn't like to get bitten by it. The most important earth you can have is from your wall sockets. Every workshop that has spinning cutting tools needs its own separate earth and every machine in it needs to be earthed.

Some tools are 'double insulated' and are OK without an earth... Until you get a shock from one! Most routers would fit that category.

A major reason for using a spindle instead a router is noise. Spindles are quiet. Its the cutting bit that makes the noise and a lot of design has gone into cutting bits in recent times to shut them up. That doesn't mean the router bit you get at the dime & 10 cent store is going be a quiet one. Just imagine standing beside a 1hp router in full flight cutting hardwood. Now imagine sitting in your car with the windows up and engine running flat out. That's the difference between a router and a spindle. Expect to pay some serious money for 2.2kw spindle. Are you sure you need that much power?

Ryadia

[ger21]

My 1.5kw spindle is 10 volt max. Hardly high voltage.

That would mean you have 150 amps going to your spindle. Sorry, but you're wrong. The 10V is the speed control signal.

Right now, I'm running a $150,000 machine with an air cooled spindle. It runs all day, every day, and has for 10 years now.

[Ryadia]

That's cool,
I measured voltage at every point in this machine. Only point with 240 volts is the input which has an Estop switch prior to reaching the transformer. Nothing comes out of the transformer at anywhere near the input line voltage. BTW I've got a 1.3 million dollar house that is air cooled too!

[Al_The_Man]

Thanks for the reply guys! I purchased this machine and it was loaded with "issues" and that is probably why it was sold. (told it was in perfect working condition, but the owner "never took the time to learn it").
Being new to this fun world and have learned a lot but feel very exposed with what I don't know, where can I go to find out about the grounding issue? I am unaware of any grounding done with this machine. I can give any information you may need in order to ensure "safe" operation.
time to start a new search today.... "proper grounding..."
Thanks,
Rockaukum

It is not only audible noise!
http://www.cnczone.com/forums/phase-...se-issues.html

As a point of interest, of all the VFD's I have installed over the years I have never used any 'special' cable from motor to VFD.
I typically used MTW/TEW for the three conductors tightly twisted and a ground ran along side.
I did in most cases use metallic flex conduit.
If you can get the shields type cheap then go for it. but when I was installing the only option was High $$ Belden specialty version.
Al.

[rockaukum]

What size wire do you recommend I use? I have reached out one seller of the vfd / spindle and they replied "2 square mm's". I have asked for clarification in terms of awg and am awaiting a reply. I will look into the pricing options for the preassembled wire or like that suggested by Al.
I am choosing to go with the 2.2kw as it comes with the er20 collet which will hold 1/2" bits.
Rockaukum

[ger21]

2 mm² is between 14 and 16 gauge. I think either will work fine.

McMaster-Carr # 7777T21
is 14awg, and $2.45/foot.

Igus is a bit more expensive.
chainflex
chainflex

[Ryadia]

I am choosing to go with the 2.2kw as it comes with the er20 collet which will hold 1/2" bits.
Rockaukum

half inch bits? this must be one hell of a machine you have. What size is the table?

[CNCMAN172]

As Ger21 pointed out that is the control voltage 0 to 10 volts and spindle rpm is proportional. 3 phase spindles are 220v or higher typically

Russ

[rockaukum]

1/2" shank on several bits, yes... is it uncommon for people to use 1/2" shank bits?
The table has a 4x8' workable surface with another 1' bay(?) off of one end. That is there in case a fourth axis is installed for turning(?).
The main bit that I plan on using with the 1/2" shank has a cutter of 1" or it might be 1 1/4" which is used for surfacing the spoil board.
The machine ran fine with the current router (2hp). That said, I am very new to this and therefor am very conservative with feed rates and such. As of now I am stuck with
28,000 rpm as the router is non adjustable and extremely noisy.
Rockaukum

[ger21]

is it uncommon for people to use 1/2" shank bits?

No, it's not.