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Spindle drive specification
« on: March 16, 2011, 09:56:24 AM »


I have an Emcoturn 120 3 ph cnc lathe am I am looking to convert to 1 ph  Mach3. To make the project more manageable it is my intention to split the overall project into smaller lumps, so for the moment I am concentrating on the Spindle drive.

My electrical knowledge is very limited so any help from the forum would be greatly appreciated particularly at this early stage to stop me going off in the wrong direction.

Existing spindle setup

The current spindle drive is a 2.6kw DC Siemens motor (GL5104-OEZ40-6JU7-Z)
with integrated  3ph cooling fan. Direct belt driven (see photos) output speed 150 -4000 rpm max torque 17.6 NM and belt driven encoder (approx 300 slots)











I have noticed on the forum that a Parker ssd 514c unit would control this motor but I had a look at the manual and it didn’t look particularly straightforward also not sure how I would tackle cooling fan. Also not sure if this motor to powerful and costly to run for hobby needs.

Question 1 Do you think it is worth persevering with this motor ?

I was thinking of saving money by going for a smaller motor say 1.5 kw with ac inverter

Question 2  Is this a false economy ? ( I want to cut threads and not sure about torque level at slower speeds)

2,4,6 pole motors !!! I am not sure what would be better for my application relating to torque, running cost and surface finish

Question 3 For average working speed say 1500 rpm.  Is it better to get a faster motor slowed down by inverter drive or slower motor speeded up by inverter?

I have noticed a massive price difference for ac inverters of the same power rating
as much as 300% the more expensive quoting vector control

Question 4 For my application is this extra cost justified? Does this just give more accurate speed control or are there any torque/ heat implications particularly at lower speed?

I have been looking at various breakout boards on the internet to see how the spindle controls are hooked up and many show inverter connections going straight back to BOB. But I have also seen speed controllers advertised and connected up to similar ac inverter drives.  Eg

http://www.cnc4pc.com/Store/osc/product_info.php?cPath=25&products_id=303

Question 5 What are the benefits of these controllers?

The lathe comes with its (very well made) own spindle encoder (see photo) approx 300 slots

Question 6 Is this too many slots for mach3 to handle and does single slot produce accurate threads?

Not sure what voltage output is for this encoder or of wiring details.

Question 7.  Do you think I should change this for new or can anyone help with info?


Any comments from the forum would be greatly appreciated. Even if you only have answer for one of the questions. It all helps

Cheers George

Offline Hood

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Re: Spindle drive specification
« Reply #1 on: March 16, 2011, 02:54:21 PM »
Do you have a link to the specs of the motor or do you have the specs?
Servo spindles are the best so I would try hard to keep it.
Do you have a drive for it and if so do you have a link to the spcs.
Hood
Re: Spindle drive specification
« Reply #2 on: March 17, 2011, 08:15:59 AM »
Hi Hood

sorry having a few problems trying to get photos loaded. will try again now.

I don't think it is a servo (but not sure) as encoder (item 54 in photo) totally separate

I do have electronic manual for motor but may have to take copies of some of relevant pages

as I think it is very big file to upload. I will wait to see what you think after viewing photos.


Re: Spindle drive specification
« Reply #3 on: March 17, 2011, 08:40:47 AM »
here is the link for the parker controller recommended. The existing drive is I believe of emcos own design and integrated into the control panel ( 20 years old and not supported now)

http://www.inverterdrive.com/group/DC-Thyristor-Drives/SSD-514-8A-Eurotherm-Shackleton-Rapier-Drives-540-/default.aspx

just in case not clear from photo encoder belt driven below main spindle
Re: Spindle drive specification
« Reply #4 on: March 17, 2011, 08:51:19 AM »
here is the two other photos
Re: Spindle drive specification
« Reply #5 on: March 17, 2011, 09:13:30 AM »
Here is motor manual (not as big as I thought)

Siemans dc motor GL5104 NLF6     ( GL5104-OEZ40-6JU7-Z)

Offline Hood

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Re: Spindle drive specification
« Reply #6 on: March 17, 2011, 04:32:54 PM »
I would certainly try and keep that motor, look at the torque, it is constant from zero rpm up to rated speed, you will not get that with an induction motor and VFD. If you do go with induction/vfd then I would say tripple the KW at least.

The manual attached doesnt really say much from what I can see and I have searched Siemens site but the model you quote doesnt seem to bring up any info. Can you take a pic of the nameplate on the motor, that might help find more ino.
Hood
Re: Spindle drive specification
« Reply #7 on: March 18, 2011, 07:54:12 AM »
Hi Hood

photos not particularly clear so also added word document with what I think they say.

what do you think would be the best way to handle integrated cooling motor as I need 1 ph supply.

!) change motor to 1 ph

2) Can parker contolller control this as well? (may be stupid question)

3) get separate controller for this?

and how do you think it should be controlled ie

1) temperature

2) always on when lathe switched on

3) always on when spindle motor running

4) other

cheers George

ps will try internet search to see if I can get any more  info motor

Offline Hood

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Re: Spindle drive specification
« Reply #8 on: March 18, 2011, 06:20:58 PM »
Just cant seem to find any Siemens specs for the motor but it does seem like its a DC servo, its high voltage though so I think you will likely struggle to find something single phase to control that :(
The Parker on single phase is only 180v DC output from  the quick look I gave the page, that would likely get you about 700rpm.
One option may be a rotary phase convertor so that you can get the 415v three phase (assuming you are UK)
If you do decide to use a normal induction motor and a VFD then I would look at something twice the Kw of the original motor as you will lose torque at low speeds, and that is where you want it. This is just from my own experience from VFDs so maybe things are better now as my VFD was maybe 10yrs old.

Other option may be to try and find an AC servo motor and drive, I use AC Servos that I picked up on eBay but they are scarce in the UK for the type I use.
Hood
« Last Edit: March 18, 2011, 06:22:41 PM by Hood »
Re: Spindle drive specification
« Reply #9 on: March 20, 2011, 04:15:30 PM »
Hi Hood

thanks for that

before I dismiss it totally I will contact siemens directly to see what they would recommend to control it. if anything

will post reply

Cheers George

PS   yes UK