I just found out my servo drivers are analog +10/-10 v What are my options?

[martyscncgarage]

Please get a better higher resolution picture of the cables connected to the Glentek spindle drive also allowing me to see the dip switch settings. I can not zoom into the photos much because the photos are lower resolution.

Marty

[Setlab]

Hi Marty, I'm not sure how to make this forum post better images. Here is a link to my unlocked google drive though https://drive.google.com/drive/folders/ ... sp=sharing with a couple more pictures of the connections that can be zoomed in on.

Thank you for looking at them.

[martyscncgarage]

I believe you may be able to use the spindle drive. However, I believe its analog input (J1-3 Signal 2+) uses a -/+ 0-10VDC analog signal. To spindle the motor Clockwise, the signal is 0 to +10VDC. To spin it in reverse, it is 0 to -10VDC. Most times it is NOT as simple as using a relay to invert the signal.

You should print your manual and mark which connections on J2 are used. In your case, J1-3, J1-4 and J1-10.
You should also mark the current switch settings of the drive.

This is a mistake people make when disassembling a control cabinet. If the control is working at the time of disassembly, you can take voltage readings on these terminals and take notes. I always leave a notepad by the machine I am working on. This can be valuable information when you are working on the conversion.

I have an email into Glentek. To see if the drive can be used with a positive 0 to 10VDC input for rotating the motor in one direction and another input to reverse the motor with the same analog input.

As I said previously, leave the spindle alone and start deciding which axis motors and drives you plan to use. Measure the current axis motor shaft and determine its frame size by measuring the flange and center to center mounting hole distances. Likely NEMA 34 Working on getting axis moving and then worry about the spindle motor.
Marty

[martyscncgarage]

Glentek got back with me.
They say there is no way to reverse the spindle without a negative 0-10VDC input.
You would need a solid state circuit to invert the polarity. It can be done, I have done it. You would use a signal to invert when the SPINREV relay closes.

The only other sure way is to replace the spindle motor and drive with a 3phase inverter duty rated motor and VFD.
I can not comment on using an AC servo as a spindle motor.

Marty

[martyscncgarage]

I had suggested to Arturo Duncan that he make a board that will take 0 to +10VDC input along with a signal to invert the output signal and they DID build the board. I had one, I have not tested it yet. Will do so soon.

https://www.cnc4pc.com/c89-10vdc-analog ... board.html

Marty

[martyscncgarage]

I had suggested to Arturo Duncan that he make a board that will take 0 to +10VDC input along with a signal to invert the output signal and they DID build the board. I had one, I have not tested it yet. Will do so soon.

https://www.cnc4pc.com/c89-10vdc-analog ... board.html

Marty

I am not so sure the CNC4PC solution would work.
I had asked for a board that would take a positive 0 to 10VDC analog signal and INVERT it when it receives another signal (reverse)
I have made such boards and supplied the circuit to CNC4PC but they didn't Isolate the output and took a kitchen sink approach, which I really hate.
They say it will work with PWM but PWM has not been released in CNC12 yet. It is being tested.


Marty

[Setlab]

Marty, we need to sit down and talk with the Centroid staff about putting you on their payroll lol. Thanks for asking around and thinking on a solution. The idea of replacing the spindle motor and drive has grown a little on me. Of the choices of a cheaper DMM servo setup vs. a 3phase and VFD combo I would lean more towards the servo option if at least just to have higher RPM and a much lighter motor. If I went the 3phase/vfd route I would have to mess around with installing an encoder for the Acorn to know what RPM or direction the spindle was going too wouldn't I?

I ordered 3 closed-loop stepper kits and that ended up being a lot more affordable than messing around with servo motors.

[martyscncgarage]

Marty, we need to sit down and talk with the Centroid staff about putting you on their payroll lol. Thanks for asking around and thinking on a solution. The idea of replacing the spindle motor and drive has grown a little on me. Of the choices of a cheaper DMM servo setup vs. a 3phase and VFD combo I would lean more towards the servo option if at least just to have higher RPM and a much lighter motor. If I went the 3phase/vfd route I would have to mess around with installing an encoder for the Acorn to know what RPM or direction the spindle was going too wouldn't I?

I ordered 3 closed-loop stepper kits and that ended up being a lot more affordable than messing around with servo motors.

Just give some serious thought to using a servo as a spindle motor. Really try and find someone that has implemented it successfully and that the performance is as least as good as the current setup.

Do not discard the current servo drive. spindle motor and harnesses.

Marty

[Muzzer]

Most servos max out around 3000rpm, rather lower than a standard 2 pole induction motor. If you want precise speed control, fit an encoder to the motor. But if you aren't doing rigid tapping, how is the precise speed or position required? Do you need an encoder or not?

Look at some real motors and see how servo motors compare with induction motors. You can get induction motors in the same packaging as servos and steppers but unless space is tight, a normal totally enclosed fan cooled (TEFC) motor is as cheap as chips.

I'd suggest you avoid trying to come up with out of the box approaches on your first system. There aren't lots of wheels lying around waiting to be reinvented.

[Setlab]

I have a long history of doing just that and making simple projects turn into way overbuilt and over-engineered beasts unfortunately. I guess RPM wise an induction motor will get me about 3600 RPM whereas the DMM servo I was looking at is 3000 RPM (limiting myself to an approximately 1hp (0.75kw) servo motor which would be a downgrade from my current old motor hp). I can see the simplicity of just hooking up a 3phase/VFD combo, the idea isn't lost quite yet. If I go the latter route I would definitely want an encoder, that's something I haven't looked into the ins and outs yet though. I'll have to look into how guys physically mount encoders to mill spindles.

Initially, max speed with on/off will probably suit my needs to learn how not to crash a milling machine. But I do want to use exact speeds/feeds to get out of the just get-er-done good eunouf approach, and having the ability to rigid tap parts would be a pretty nice feature I would really like to grow into. Rigid tapping can be an easy thing for me to forget about if the price starts to approach another grand though.