[HereinCS]

I was just about to buy the 4kw chinese made spindle motor. For some reason, I thought that it's only equivalent to 3 HP. But talking with Dealers Industrial, I found out that its more like 5hp. That makes the VFD choice much more limited. Am I using too much power? Maybe I'll go to a 2.2kw spindle? Is that enough to cut wood and aluminum? Is an ER16 collet rather than an ER20 a big deal?

In regards to the VFD, I read that I should look for a sensorless speed controller? Did I remember incorrectly? Is this important?

Thanks

[UUU]

I can cut wood and aluminium with a saw, and I don't put out 2.2KW

[wcarrothers1]

down side of the smaller ER is I don't think you can get a 1/2" collet untill ER20 size.. That would sorta suck if you ask me seeing I have alot of .5" bits..

they might have another option but I think the biggest VFD automation direct sells which can operate from single phase is 3hp. I'm sure some one else makes a bigger one that can run from single phase input. get bigger then that and you would have to run a rotary phase converter. I've got one to run my bridgeport although I will admit I would not want to run that all day just to operate my router mill spindle.

b.

[jsheerin]

http://www.google.com/search?hl=en&c...=&oq=&gs_rfai=

4kW = 5.36HP.

Personally I have a 3.7kW spindle and plan to drive it with a Mitsubishi A520 7.5kW drive. This is a 3 phase input power drive, but you can hook it up to single phase if you derate it by a factor of 2.

As far as power, you can cut wood and aluminum with much less power. You just can't cut it as quickly. You can probably search on google and find a machining calculator for aluminum that will give you an idea of how much power you need for a given material removal rate.

I believe what sensorless vector control does in a VFD is give you more torque at low speeds without feedback from an encoder. I've used several VFD's and never really noticed my motor bog down, although I was taking light cuts. So the answer there might be that it could come in handy more if you plan on taking cuts near the limit of your drive / spindle at low speeds, but otherwise it's not strictly necessary.

[underthetire]

I've had very good luck with this company for all my drive stuff
http://www.a-m-c.com/index.html

[HereinCS]

Thanks for the advice guys. I'm glad I discussed it here prior to buying the motor. A household 220v outlet is single phase right? The most that any single phase vfd will put out is 3 hp? That means that, since I'll buy an air cooled spindle, I'll use a 1.5 kw motor. This is only 2 hp. Worse, it only has a er16 collet. Now I'm back to square one. Maybe I'll just buy their package with the VFD.

[jsheerin]

Like I said, you can use some 3 phase input vfd's off of single phase. It's not the cheapest way to go if you're buying new though, but you can get in to higher power drives that way and it's what I'll be doing. From many posts here, I would not buy a Chinese VFD.

[Al_The_Man]

In regards to the VFD, I read that I should look for a sensorless speed controller? Did I remember incorrectly? Is this important?

Thanks

Most medium/high end VFD's are Sensorless vector, this refers to the VFD's ability to take a model of the motor and attempt to maintain the optimum vector angle between the rotor and the winding current.
The alternatives are variable speed, which basically outputs the frequency without knowledge of the vector angle.
The opposite end is pulse feedback on the motor rotor to VFD.
Any VFD that has a teach mode for your individual motor is sensorless vector.
Al.

[HereinCS]

Is TECO a good name for VFD?

[awerby]

Is TECO a good name for VFD?

I got one new from Dealer's Electric, and tried to set it up using the (rather cryptic) manual. It didn't seem to be working too well, running hot and sounding funny, so I tried experimenting with various software settings hoping for a healthier response from my spindle. Suddenly there was a flash-bang from the VFD, a bad smell, and no further action from the motor. We sent the VFD back to TECO for evaluation; their tech said it must have been "struck by lightning" and that he couldn't be responsible for "acts of God". I was somewhat dumbstruck at this, wondering if God was working in their factory all this time, or if my experimentation was more inspired than I'd thought. But nothing could persuade them that this was something they were responsible for in any way, despite the unit's still being under "warranty" (read the fine print...)

Fortunately, Harold at Dealer's Electric is a stand-up guy, and he sent me a new Hitachi VFD, which had a much more comprehensible manual (with an index!), set up much easier, and is working to this day. I can heartily recommend Dealer's Electric and Hitachi's VFDs - TECO, not so much...

Andrew Werby
www.computersculpture.com

[wcarrothers1]

My ekstrom is a 2.68hp 8.8A 220v one with a er25 collet.. Working with the 3hp vfd from automationdirect which has single phase input 220.

Seems to work good.. But mroe expencive then any of the china ones.



b.

[HereinCS]

What would happen if I power a 3kw spindle with a 3hp vfd? Does it just not make the power? or is there more to it than that?

[Al_The_Man]

Probably go into fault, over current limit and cut out on you, also over voltage on decel etc. Nuisance tripping.
3Kw is ~4hp.
Al.

[HereinCS]

Thanks Al for all your help.

This spindle/vfd choice is driving me nuts. I really wanted a higher hp motor for faster cutting, but finding a vfd that takes household single phase beyond 3 hp is almost impossible. Almost:

what do you think of this Seems like 36+ amp would exceed my capacities anyways.

Is there a way to get 220v 3 phase in a home?

Also, can I use a 3 hp vfd with a 2hp spindle motor?

[UUU]

Yes you can run a smaller motor from a bigger inverter. I do it.

Most inverters will have a paramter-set current limiter, so you can de-rate the inverter to match the motor. If the motor draws more current than the set value, then the inverter will stop and show an error.

This same feature is what stops you running a big motor from a small inverter. As previously noted in this thread, the motor will attempt to draw more current than the inverter can supply and it will shut down. This is not speed dependent, it will happen as soon as you start up.

As an aside - my VFD has an output signal when in error condition that I'm wiring to my break-out board, so if the spindle stops because of an inverter error, then the stepper drives and control software register an e-stop.

As another note, I've found a UK supplier listing 5HP single to three phase 240V inverters and single 240V to three phase 415V at 7.5HP (at mega-money). I've not bought from them so this is not any kind of recommendation, just a note that such things are avialable. www.drivesdirect.co.uk

[diyengineer]

Just build a rotary converter, takes single phase 220 to a electric motor that develops and outputs 3 phase. Walla.

Im sure there are at least a million tutorials and walk throughs on you-tube as well as the internet. Just a simple quick search from google and you will find hords of information for free.

Dont bother with the solid state cheapo ones, they dont work with crap. You need a rotary converter. My friend uses a 7HP GE electric motor and a few capacitors i believe to make his 3 phase for his bigger machines (lathe and mill).

Thanks Al for all your help.

This spindle/vfd choice is driving me nuts. I really wanted a higher hp motor for faster cutting, but finding a vfd that takes household single phase beyond 3 hp is almost impossible. Almost:

what do you think of this Seems like 36+ amp would exceed my capacities anyways.

Is there a way to get 220v 3 phase in a home?

Also, can I use a 3 hp vfd with a 2hp spindle motor?

[UUU]

Like the previous respondent I have seen three-phase machines run from a capacitor-based converter, with a pilot motor (a small free-running second motor).

These have been entirely satisfactory in every way on the machines I have seen, but have had spindle speed control via belts and gearbox, as the alternating current frequency and therefore motor speed is fixed by the supply.

On my mill there is no option to control spindle speed other than by changing motor speed, so an inverter was the preferred option. You may not need speed control.

Also I can control start, stop and speed readily from the (Mach3) control software. You'll need a meaty relay if you go the converter route or you may be happy with manual switching.

I also echo the previous resondent's sentiment - don't go cheapo. You'll get a better and more reliable performance from decent quality kit, even if the rated power seems lower.

[wcarrothers1]

Rotary phase converter is one way to go to get 3 phase in the home. Really the only way to go actually.. Although you waist more electricity in the process so long term would cost a bit more to do. Although I'd bet a large single phase input vfd capiable of switching and running a larger motor would have efficiency issues as well so might be a wash running a large single phase vfd vs a 3 phase vfd and a rotary converter.

I use my rotary for my bridgeport. Would choose to run a smaller spindle motor rather then run my rotary phase converter all day to power a larger one.. It isn't like i've ever even come close to stalling my Ekstrom spindle. This isn't like comparing HP to a standard router or Anything even close.. My big portercable router was NOTHING compaired to my 2.6hp ekstrom far as power is concerned..

b.

[HereinCS]

Please walk me through this. Based on the comments below:

1. I don't even need a vfd?
2. Thanks for the suggestion on the phase converters. The rotary ones aren't too high priced. I honestly don't know what 1 and 3 phase means, and that's my next step in this learning process. My question is that this goes in my home. I'm likely limited by the current available anyways right? So a 5 hp motor may strip all the current in my home right?

[jsheerin]

You do need a VFD. High speed spindle typically require AC power at frequencies up to 400hz. AC power coming into your house (or out of a 3ph rotary converter) is at 60hz.

Look up single and 3 phase power - there are lots of explanations available online.

Whether or not you are limited in available current depends on how your house is wired. Personally I have a 50A 240V line run in my garage to power things like this, so potentially I could source 12kW of power from that (16HP) although various losses would likely limit me to something lower. It is fairly typical for houses to have 200A services installed to run the entire house, so it is very possible that you could spare enough current to run a large motor without getting in the way of other appliances. Alternatively, turn off any major power consuming devices when you want to use your router. ;>