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  #1  
Old Fri 14 August 2009, 04:33
silverdog
Just call me: Sergio #70
 
Rome
Italy
VFD usage

Hi, I have no experience with VFD, so I ask this question:
I will buy a VFD plus a spindle, I understand the usage and the utility of the VFD for the spindle .... but the spindle can also be conected directly to the current ? or they are native for the use with a VFD ? I ask this because I wonder if I can use VFDs for other tools, In detail I have a professional 3ph bench drill wich has only 4 mechanical speeds ...... will I be able to have more control over speeds with a VFD ?
thanks
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  #2  
Old Fri 14 August 2009, 04:46
gixi
Just call me: Marius (AVO) #32
 
Bucharest
Romania
Send a message via Yahoo to gixi
Buy from the Italian dealer from where I also get a spindle with VFD and this guy was kind enough to make all the setings. He even install the wires. It's the shortcut .
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  #3  
Old Fri 14 August 2009, 05:04
Alan_c
Just call me: Alan (#11)
 
Cape Town (Western Cape)
South Africa
Send a message via Skype™ to Alan_c
The spindle can be connected directly but it will have only one speed (and I think that will be quite slow) To get the benefit of a spindle you must use the VFD.

For your bench drill it is possible to add a VFD to the existing motor to give you greater speed control - speak to your supplier to match the correct unit for your motors capacity.
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  #4  
Old Fri 14 August 2009, 07:15
silverdog
Just call me: Sergio #70
 
Rome
Italy
Thank you Marius and Alan
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  #5  
Old Fri 14 August 2009, 07:33
bradm
Just call me: Brad #10
 
Somerville(MA)
United States of America
Whoa! I don't think you can connect a spindle directly unless it's HZ rating matches the powerline, which is unlikely.

A typical 2.2KW spindle would be rated for 240v, 8a per phase, 400Hz, 24000 RPM

A typical three phase powerline would be rated for 240v, 50 or 60Hz.

So the spindle would be spinning at about 1/8 of it's rated speed, or 3000/3600 RPM.

It's not clear to me that there is anything to limit the current flowing into the spindle in this configuration, however. A VFD would ensure that the current at 3000 RPM was appropriately low, E.G. in the 1 amp range. Directly connected, the spindle windings can draw full current (8A or so) at that low speed, and burn themselves up rather quickly.

I believe that this is also the failure mode if you fail to correctly program your VFD for the Hz rating of your spindle motor. You end up committing exactly the same error, although with a pleasant controlled speed ramp up before you blow up the spindle. And probably the VFD.

I think. Somebody else will surely correct and amplify this point.

So, you can, in some cases, add a VFD to an existing motor to get speed control; albeit possibly with some derating of the motor capacity to deal with additional heating related to running the motor outside it's design speed. That's typical for a basic 60Hz rated three phase motor, some of which are explicitly designed for VFD control by using a conservative thermal design. But you cannot take a motor and run it on a supply that is radically different from it's design speed without an intervening VFD, which is typical for a spindle motor.

Last edited by bradm; Fri 14 August 2009 at 07:38.. Reason: Add thought about VFD misconfiguration.
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  #6  
Old Sun 16 August 2009, 08:23
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Brad, I think that you are mistaken; a spindle can be connected direct to mains supply. (I havn't done it myself). The VFD only limits the current when the spindle gets mechanically overloaded. An unloaded motor (or spindle) limits its own current by the resistance in its coils. A spindle and a 3-phase motor are one and the same thing from an electrical viewpoint - a spindle is just mechanically designed to be able to go faster.
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  #7  
Old Sun 16 August 2009, 09:49
KenC
Just call me: Ken
 
Klang
Malaysia
Brad, 400hz is the frequency the spindle can take. You are right that the speed of spindle off 50/60hz mains. Garald is correct in pointing out the over current is not a problem with electrical load. For induction machines (motor & generator), there is a relationship between the frequency and voltage for max torque at various speed as there are no point to vary the speed without maintaining torque, the VFD make sure this happen. This should help better understanding.
With that in mind, the limiting speed of induction motor is the bearing. hence any induction motor can be use as spindle/tool head. (bearing should take radial & axial load).
The motor is not considered as working outside of the capacity as long as the Voltage Vs frequency relationship is kept well. The only concern I have is cooling, if the motor runs too slow, say 50~100rpm, the fan might not be able to provide sufficient air to cool the motor.

I have yet to experience 2.2kw VFD spindles, but has some experience with VFD from 5kw to 150kw, we can eliminate surge current during start up and vary the speed for fine tuning process flow. I can start a 150kW Biomass Boiler Induction Fan + other auxilary load mounting to about 250kW with a 300kW genset (happyly) by stepping up the motors' speed with VFDs. Other conventional starting method will force at least a 500kW genset to do the same work. and the spare capacity will go idle after 5 minutes plus a big capital cost.

Last edited by KenC; Sun 16 August 2009 at 10:10..
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  #8  
Old Sun 16 August 2009, 13:05
silverdog
Just call me: Sergio #70
 
Rome
Italy
Wow I'm always astonished by the skill and professionality of the members of this forum !
thank everybody
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  #9  
Old Mon 14 September 2009, 16:15
larry1larry
Just call me: larry
 
toronto
Canada
Maybe stupid questions.
If you need 220V/3Ph out i assume you need 220 single Phase in if you do not have 220/3Ph.
The reason I ask is some of the spindles are for 380V/3Ph.I think a transformer is in order for larger spindles.
Does a vfd eliminate the need for a roto phase?
Larry
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  #10  
Old Mon 14 September 2009, 16:35
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Larry,
Depending on the size of your spindle, you can power your amplifier drive via single phase 220V. The VFD converts the power to 3 phase for the electric motor use. The single phase VFD have limitations on HP rating. Thus, usually limited to under 3 to 5hp range in the single phase.

Sean
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  #11  
Old Mon 14 September 2009, 18:51
larry1larry
Just call me: larry
 
toronto
Canada
Thanks Sean that answered my question.
I agree over 3 hp most spindles need 380V.This limits the home shop guys to 3HP max.
My shop voltage in Ontario Canada is 575V/3Ph so any large spindle can be handled with a step down transforner which is cheap.To step up from 220 to 380 makes it necessary to win a lottery.For the guys with 220 single or 3 phase make sure your spindle is 220/3phase.Most of Keling's spindles are 220 but the odd one is 380V.
Larry
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  #12  
Old Wed 16 September 2009, 17:19
larry1larry
Just call me: larry
 
toronto
Canada
On another fourm with huanyang VFD'sI appears the main problems are some or all the pushbuttons do not work.One supplier is sending buyers 10 spare switches and changed to another brand.
Just currious,does the adminstration of the forum delete posts they do not like.I am looking for a post yesterday or early to-day about Brazillian spindles.
Thanks
Larry
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  #13  
Old Wed 16 September 2009, 18:50
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Larry,
Gerald does, from time to time, prune the forums to keep everything in top shape. Sometimes posts are a blatant advertisement, perhaps that is why it got pruned, or perhaps moved to the appropriate section.
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  #14  
Old Wed 16 September 2009, 19:27
larry1larry
Just call me: larry
 
toronto
Canada
Heath,I suppose the post got pruned as it was blatant advertisement,but it answered many questions for me.I have been re-searching Chinese spindles on E-bay,Keling,Made in China etc and the powe ratings are all over the place.The only difference between similar spindles seems to be weight.The watt ratings and amperage say 4 instance a 2.2Kw spindle are not consisant.Chinese 2.2 Kw spindles can be 7Kg or 14Kg.I have decided to rate Chinese spindles by weight.I found a 4KW spindle that is more like a 6Kw spindle.this baby is 28Kg.From...flyingelectronic on made in China.
They have 2 2.2Kw spindles one is 7Kg the other 14Kg what is the difference?
On the other hand.I would choose a chinese 2.2 Kw spindle over a screaming Porter cable.I will change over to Aussie language.
A Chinse spindle will let you grin like a shot fox.Be a happyittle vegemite.
The pruned post answered and made more questions for me.
We can decide for our selves if a post is revelent or not.
I am just trying to look out for the members.
I suppose I will get pruned.Bye
Larry
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  #15  
Old Wed 16 September 2009, 19:38
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Larry,
I am not any authority on Chinese or Brazilian spindles. I am sure that the more expensive spindles will possibly have better quality components than the cheaper ones, regarless of where they are manufactured. Maybe determine your budget and search out the spindles that meet your financial and cutting needs. Check out the Marketplace, there is at least one post there of a supplier who has some happy customers on this site.
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  #16  
Old Wed 16 September 2009, 22:08
Besser
Just call me: Besser
 
Vic
Australia
Sergio, to answer your original question-
Yes you can move your VFD from machine to machine. 3ph motors wired to your VFD can become variable speed. (make sure its correctly wired (star or delta)) You do need to be mindful of heat dissipation for low speeds.
Basically a VFD is like a computer that accepts AC in and turns it into DC then chops it up into little pieces and spits it out the other side. This DC output is varied in voltage and length(time) to create a psudo sine pattern like an AC wave. It's the time length per DC shot that gives us the frequency. Some drives drop certain levels of DC injections as the HZ increase to be able to manage the HZ and this practice leads to increased heat generation, more stray noise (shield your motor) and less efficiency.
So do your research on the Drill and spec the motor and VFD to make sure they will be happy together within the speed and power range you are expecting to use it for.
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  #17  
Old Wed 16 September 2009, 22:51
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Yes Larry, I dumped that post and banned the poster. His only contribution to this forum was to make wild statements about Chinese vs. Brazilian spindles, with a clear intent of shooting the Chinese down and promoting his own product. That type of post and poster are not welcome here. He is gone for now, let us move on.
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  #18  
Old Wed 16 September 2009, 23:33
Claudiu
Just call me: Claus #43
 
Arad
Romania
About the Spindle...

Hi Larry,

If you are looking for a Spindle, with good quality and reasonable price maybe you check GIXI`s comments on the italian one with VFD, which came allready set up and wired by the manufacturer.
Here the link to the thread. Post #96.

Maybe it suits your needs.

Claus
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  #19  
Old Thu 17 September 2009, 08:45
liaoh75
Just call me: David
 
Taibao
Taiwan
I would like to ask the forum members a question. I just got a 3KW spindle from China and have opted not to buy their HYN.... Inverter which they will sell as a matched kit. I've read an unhealthy amount of complaints about their inverter on CNC Zone but not too much negative chatter on the spindle motor itself.

I will be using a Rich 5HP inverter (which is more than I need) instead that was free to me. I'll post model number later as I don't have it with me right now. I was told by locals that it's fine, but does anyone have any experience with this? Specifically, can I use a 5HP inverter with a 3KW (4HP) motor?
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  #20  
Old Thu 17 September 2009, 09:34
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
You can use a 5HP inverter with a 4HP spindle.
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  #21  
Old Thu 17 September 2009, 18:40
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
David,
As Gerald mentioned, you may use the 5hp inverter. Look in the user manual, you should be able to limit the Current output of the amplifier to not "over drive" the spindle.....Just like a Gecko and the current set resistors.

Sean
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  #22  
Old Fri 18 September 2009, 10:33
liaoh75
Just call me: David
 
Taibao
Taiwan
Thanks Gerald and Sean for the reply. I'll look into the current limit in the inverter setting.
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  #23  
Old Fri 18 September 2009, 16:34
larry1larry
Just call me: larry
 
toronto
Canada
Vfd

Hey Dave it is good to use a VFD of higher HP as VFD do not push current only supplyes what the motor wants.A 10HP or more VFD is OK.Too small aVfd will put a strain on the VFD.You can set current limit to protect the spindle.
BTW what is the voltage and current ratings of your spindle?Do you have 3 ph power?
Larry
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  #24  
Old Sun 20 September 2009, 01:58
liaoh75
Just call me: David
 
Taibao
Taiwan
Larry, my spindle is rated for 220V. I do have 3phase power at the shop so that is what I'm feeding my inverter but the guy that gave me the inverter says I can run in on Single phase just fine. He added that as long as the motor you are driving is under 7 HP, single phase power to the inverter will be work. I have no experience with this, but that is what I was told. -David
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  #25  
Old Sun 20 September 2009, 16:49
larry1larry
Just call me: larry
 
toronto
Canada
Vfd

Dave if you have 3/phase 220 use it.Using single phase would require larger wiring and a loss of power.
Larry
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  #26  
Old Sun 20 September 2009, 22:21
liaoh75
Just call me: David
 
Taibao
Taiwan
Larry, thanks for the info. I'm new to this inverter thing and let me tell you, it's been a sobering experience thus far.
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  #27  
Old Mon 21 September 2009, 15:35
Besser
Just call me: Besser
 
Vic
Australia
Dave, single or 3 phase fed inverters(VFD) do the same thing (read post 16) They make quasi 3 phase. If you have a Chinese spindle 3hp a single phase inverter will be fine. I would caution on RF output from inverters and the quality of the sine wave simulation. they make a lot of radio noise and can heat up motors (but I havnt read any issues with the chinese ones). If you box them in a cage and ground the faraday cage then you can save your surrounding gear.
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  #28  
Old Fri 25 September 2009, 03:21
BartDeckers
Just call me: Bart_D
 
Antwerpen
Belgium
Matching VFD for a spindle

I found following info on the net somewhere:

The rotational speed (speed of the cutting edge) of the routerbit depends on the diameter of the bit. This is one of the reasons why we need a VFD for a spindle.

Bitsize versus rpm:

smaller than 1" : 22.000 to 24.000 rpm
between 1" and 2" : 18.000 to 22.000 rpm
between 2" and 2 1/2" : 12.000 to 16.000 rpm
between 2 1/2" and 3 1/2" : 8.000 to 12.000 rpm

I have no idea how correct this info is but it makes sense to me that the rpm's wil have to change with the diameter of the bit.

My question is:

I would like to buy a 2.1 kW 24.000 rpm (max) 3 fase 230 Volt spindle from HSD. I also found a 2.2 kW VFD from Delta (VFD022B21 A) which can be connected to both a 1 fase 230 Volt net as also a 3 fase 230 Volt net.

Will there be a difference in the performance of the spindle if I connect the VFD to 1 fase or to 3 fase? (I have a 3 fase 230 Volt net at home but maybe will move the MM to another place later on)

Last edited by BartDeckers; Fri 25 September 2009 at 03:47..
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  #29  
Old Fri 25 September 2009, 09:00
bradm
Just call me: Brad #10
 
Somerville(MA)
United States of America
Bart, There will be no difference in the output of the VFD, or the performance of the spindle. The VFD always outputs 3phase to the spindle.

The VFD will draw a higher amperage from single phase power than it would from three phase, as it is drawing the same amount of total wattage from two conductors rather than three.
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  #30  
Old Fri 25 September 2009, 09:09
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Some VFD's give a lower output when connected to single phase instead of 3 phase, but it seems like the Delta VFD022B21 A is capable of giving full output for both types of input. (I have checked the sales brochure for the Delta).
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