How do I setup a 2.2kw spindle so iy could be indexed and held in that position?

Hi,

A few questions:

1 - I want to use a 2.2kw water cooled Chinese spindle and gear it down 4:1 to an R8 spindle on a milling head I'm building.
The Chinese spindle can run at 20,000 RPM, so the R8 spindle would be 5000 RPM max.
Does anyone know of possible problems with that idea?

2 - Would it be possible to index and hold the R8 spindle in that indexed position using an encoder on the R8 spindle end?
Does the 2.2kw water cooled Chinese spindle have the ability to brake and hold a position?
If this could be done... how would it need to be wired and setup in Mach3?
Please explain any suggestions or problems with the above...

Thanks,
Ray

Quote:

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Originally Posted by allaces

Hi,

A few questions:

1 - I want to use a 2.2kw water cooled Chinese spindle and gear it down 4:1 to an R8 spindle on a milling head I'm building.
The Chinese spindle can run at 20,000 RPM, so the R8 spindle would be 5000 RPM max.
Does anyone know of possible problems with that idea?

2 - Would it be possible to index and hold the R8 spindle in that indexed position using an encoder on the R8 spindle end?
Does the 2.2kw water cooled Chinese spindle have the ability to brake and hold a position?
If this could be done... how would it need to be wired and setup in Mach3?
Please explain any suggestions or problems with the above...

Thanks,
Ray

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No the spindle does not have the ability to hold a position, they can do braking with a VFD Drive that has a braking Resistor ( normally extra for this ) not a good choice of motor to do this with, if you got a AC servo motor you would solve all your problems 5000 is what some will run at depending on size and you can position it how ever you want , in Mach3 you could set it up as an axes

Mactec54,

Thank you for your reply. I need more help!

Keeping in mind the "cost" and the "resulting torque" value at the R8 spindle from the 4:1 reduction of my flawed 2.2kw setup...

Can you direct me to a "110 VAC Servo" that can handle the "5000 RPM" and provide similar "Torque" to the R8 spindle for similar "End Price"?

Ray

Hi,
I bought a second hand 1.8kW 3500 rpm Allen Bradley AC servo and matching drive for about $600 USD (delivered) in New Zealand. Still had to buy cables and
the Rockwell setup software for use as a directly coupled spindle motor, all up about $900USD. Absolutely delighted with how it works.

Quite frankly a lot of that Chinese stuff is that junky that second hand US/European/Japanese stuff is better. AC servos when used as spindles can be indexed very
accurately, programmed in velocity OR torque OR position modes, or maybe a primary mode (velocity) with a secondary mode (position),they are almost too good!.

Have a closer look at secondhand servos and matching drives on EBay. If you are unfamiliar with AC servos I would get a servo and matching drive from the same
manufacturer. You can mix and match servos and drives IF you know what you are doing. I'm glad I have a matching drive...I think I would have struggled
to adapt my servo to another manufacturers drive.

Delta and Teco are good Chinese/Taiwanese brands but I wouldn't trust any of the cheaper Chinese stuff. Beware also that cables and setup software
(depending on the brand) may not be included if buying second hand.

You might like to look at new DMM servos, although I think all the higher power ones are 230V. The company is Canadian and have a good reputation for support
but they manufacture in China so the prices a pretty compelling. Quality at a good price.......

https://store.dmm-tech.com/products/...ac-servo-motor
https://store.dmm-tech.com/products/...nt=20981907526
https://store.dmm-tech.com/collectio...Servo%20Cables

Craig

Quote:

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Originally Posted by allaces

Mactec54,

Thank you for your reply. I need more help!

Keeping in mind the "cost" and the "resulting torque" value at the R8 spindle from the 4:1 reduction of my flawed 2.2kw setup...

Can you direct me to a "110 VAC Servo" that can handle the "5000 RPM" and provide similar "Torque" to the R8 spindle for similar "End Price"?

Ray

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If you only have 120v supply then forget the 2.2Kw they are junk when run with 120v NA supply they need 240v to be anywhere half decent

Dmm can run on 120v/240v so check them out to see what they have to offer DMM | Technology Solutions | AC SERVO DRIVE | AC SERVO MOTOR | ROTARY ENCODER

Quote:

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Originally Posted by mactec54

If you only have 120v supply then forget the 2.2Kw they are junk when run with 120v NA supply they need 240v to be anywhere half decent

Dmm can run on 120v/240v so check them out to see what they have to offer DMM | Technology Solutions | AC SERVO DRIVE | AC SERVO MOTOR | ROTARY ENCODER

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I checked the link you provided. They do look like high end and very suitable for the application, but the price is probably over my budget for a hobby machine (I could not find any prices).

I appreciate your input even though I may be on the lower end of the price scale.

120VAC or 240VAC is not a problem if a 240VAC spindle is a better choice.

I know I could buy the "best of the best" if the end price is not an issue...

What do you think about the other questions I asked?
- Total comparative cost for both
- Encoder on the R8 spindle to achieve indexing of the 2.2kw spindle
- Torque comparison for both at all RPM range - using 4:1 on the 2.2kw spindle

I'm trying to get something priced reasonably that would fit my hobby needs.

Thank you,
Ray

Have a look at the ClearPath servo motors. They have a wide set of ratings, operating parameters and modes including the ability to set them to move to one of 4 pre-programmed positions (depending on modes). They might not give the RPM's you need however.

How you would integate this into what you are building might be a different question.

Hi,
Clearpath servos are nice but expensive, The dollars per watt is almost double Delta or DMM. They capture sales by marketing them as a 'replacement
for a stepper' and that attracts a lot of new customers, who pay too much for them.

If you need an indexing spindle of moderate torque then there is NO ACCEPTABLE low cost solutions. Any of the low cost solutions like
cheap Chinese asynchronous motors and VFDs are not indexable and still would need significant gear or belt reduction (did you say transmission loses?)
to drive an R8 spindle.

I suspect that if you buy something like this then you'll find it does not do the job you wanted and that makes it VERY EXPENSIVE even if it did not cost
a great deal.

Genuine indexing requires a servo with an encoder. New AC servos of good quality but still fair prices are Delta and DMM. My Allen Bradley servo
is very similar to this:
https://www.ebay.com/itm/ALLEN-BRADL....c100005.m1851
And the servo drive:
https://www.ebay.com/itm/Allen-Bradl...53.m1438.l2649

So even second hand, really good quality from the US, Japan and Europe are expensive, on the other hand they work REALLY WELL.

I think Matec54 is right, expecting 2.2kW from a 120V supply is unrealistic.

I think also you have to revise your budget upwards somewhat or risk buying what you hope is a cheap solution only to find it doesn't work as well as you hoped.
A close inspection of EBay may result in a good buy. Baldor servo motors are well represented often at good prices and are great motors. Unfortunately the matching
servo drives are very expensive. You might alternately find a brushed servo for which there may well be cheaper DC servo drives.

Craig

joeavaerage,

Thank you for taking the time to explain this to me.
I appreciate input from those with experience in areas I don't have.
I now have a better chance of selecting a better solution for my projects.

When I contacted a supplier of these Chinese spindles. they told me that the performance of 120V or 240V would be similar except that the amp requirement would be double for 120V system. I have a 12" radial arm saw that I bought many years ago that can run on either 120V or 240V and... to me... the performance is not noticeable either way it's wired, except that you need double the amps on the 120 line when you run it on 120V. I thought the same would be the case for the 2.2kw spindles.

Thanks for your input,
Ray

Hi,

Quote:

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except that you need double the amps on the 120 line when you run it on 120V. I thought the same would be the case for the 2.2kw spindles

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That is essentially correct. The problem is that with the 0.5-0.6 power factor common with VFDs the even at 240V 2.2kW could take 20A or more. Now you want to double
the current to run at 120V is quite an ask!!. At about 2kW and above the majority of servo drives require three phase and 400V line-line at that. I suspect genuine 120V servos are very
rare indeed beyond 1kW. Your choice would be limited and probably expensive.

AC servos get their torque by having more pole-pairs, or how they are wound. 24000 rpm asynchronous spindles have one pole pair per phase, called two pole
in the US, with a 400Hz VFD. A typical AC servo will have four pole-pair per phase, or 8 pole in US speak, with a servo drive capable of 400Hz. The servo
will have four times the torque of the asynchronous spindle but 1/4 of the revs.

You can get asynchronous spindles with two, three and four pole-pair per phase but they tend to be specialized and built for industrial applications and very
expensive, even more than a servo. Even then asynchronous spindles would need to be fitted with an ecoder or resolver to be indexable, way WAY out
of your budget.

I recommend you try an AC servo, I suspect you would be surprised just how much grunt a 1kW or 1.3kW Ac servo can have. Servos commonly have a short term
torque overload of three or four times their rated torque. Obviously they will overheat if you attempt to get more than their rated torque continuously but that
short term overload can certainly make you believe that the servo is much more powerful than the rating suggests.

Craig

Quote:

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Originally Posted by joeavaerage

Hi,

... I recommend you try an AC servo, I suspect you would be surprised just how much grunt a 1kW or 1.3kW Ac servo can have. Servos commonly have a short term
torque overload of three or four times their rated torque. Obviously they will overheat if you attempt to get more than their rated torque continuously but that
short term overload can certainly make you believe that the servo is much more powerful than the rating suggests.

Craig

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Craig,

I will definitely consider your recommendation for 1kW or 1.3kW Ac servo. From what you explained... it probably would be very sufficient for my project and clearly makes more sense that my original idea , not that my original idea made any sense to start with:). I'm amazed that people like yourself with the knowledge you have... take the time and can be even be bothered to advise people with shortcomings like me.

TOTALLY APPRECIATED!

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Craig,

I already have a VFD like this one:

https://www.ebay.com/itm/2-2KW-3HP-V...JHDP:rk:3:pf:0

Would the following servo be a good match for this VFD and my project?

https://www.ebay.com/itm/ALLEN-BRADL...frcectupt=true

My project being a small CNC lathe with a custom R8 spindle which would be used for machining small shafts and being able to index the spindle for machining grooves, keyways, drill holes, etc... using live tooling.

Thanks,
Ray

Hi,
a VFD will not work with an AC servo, or at least not well.. You need a servo drive. Some VFDs (sensorless vector drives)
do work but you will be disappointed at the speed range and robustness of motion and they CANNOT be indexed (positioned).

There are similarities between a VFD and a servo drive, there are differences too. In particular VFDs can't index or position.

You need an Allen Bradley servo drive like that I linked to before.
Model number 2098-DSD-020.

https://www.ebay.com/itm/Allen-Bradl...TlX3:rk:6:pf:0

The 2098-DSD-020 model is 10A continuous and 30 A peak, ideal for the 1.3kW servo you are looking at.
There is a model 2098-DSD-010 which is 5A cont and 15A peak which tend to be cheaper. It would drive your servo but it would lose some of it overload
capacity which would be a shame.

There is another model 2098-DSD-030 which is 15A cont 30A peak. This is the biggest single phase input servo drive that I know of, They tend to be $300-$500
when you can get them. I have an 020 model and use it on a 1.8kW servo, it came with the servo. I would have hung out and bought an 030 model if the servo
didn't already have one.

Only one thing further to ensure compatibility with the servo is to check the type of encoder. The MPL-A320P-SJ22AA part of the model number of the servo
relates to the encoder and the plugs used on this particular servo. Allen Bradley used a number of encoders, including a basic 2000 line incremental model,
like mine but also various absolute and sin/cos types. It would pay to check that the encoder can be matched to the drive you select.

What may not be readily apparent from the pic of the servo you linked to is that the motor plug is a bit trick....you cannot just buy a plug and solder in some wires.
Its a shame someone cut the cables short, particularly the servo power cable. If your installation allows the servo drive to be close to the servo you could use
the piece of cable left over, otherwise you will be up for cables and they could be as much as the servo!

I got lucky and bought a new servo power cable off EBay, new old stock for $100 USD shipped to New Zealand, but $200USD is more normal. I made the encoder
cable, electronics is my thing and I had access to Element14 parts. Even then the plug cost $50 USD.

Otherwise the Allen Bradley servo is a good quality unit and will work well for you. When you get it you will need the Rockwell setup software but you will simply
be amazed at the flexibility of control modes, monitoring, reporting and tuning options.

Craig