Spindle Motor Advice

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15 Aug 2020 23:25 #178333 by BeagleBrainz
Spindle Motor Advice was created by BeagleBrainz
I've just ordered a belt drive kit for my BF20L (G0704 to those across the pond) and am looking to replace the stock motor.
Please don't suggest a treadmill motor, coming from the repair\service industry for exercise equipment I don't want to deal with one nor the controller.
I have been looking at a brushless DC motor here:
www.emppl.com.au/collections/brushless-d...1000w-3500rpm-m090-l
or the 750w option
www.emppl.com.au/collections/brushless-d...-750w-3500rpm-m090-m
Along with their recommended controller, on the surface it looks expensive but the supplier is in Australia, so should have a saving on delivery costs.

Or would an AC servo motor be an option such as:
dmm-store-shopify.myshopify.com/products...-75kw-ac-servo-motor

What other options are there ?
Keep in mind that almost all my milling projects have been in steel so far. If possible I would like something with a 14mm shaft

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16 Aug 2020 08:28 #178367 by rodw
Replied by rodw on topic Spindle Motor Advice
a 3 phase motor with a VFD would be the cheapest option if you can get one the right form factor.

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16 Aug 2020 08:34 #178369 by BeagleBrainz
Replied by BeagleBrainz on topic Spindle Motor Advice
I though of that Rod,I have one for the Myford ML7\Super 7 I'm putting together, but it weighs a ton and I'd have to upgrade the Z axis motor & drive to cope.

I'll give emppl a shout Monday and see what they reckon.

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17 Aug 2020 22:53 #178544 by JohnnyCNC
Replied by JohnnyCNC on topic Spindle Motor Advice
I used this one on a Sieg X3 which is very similar to a G0704. It drives the spindle via a toothed belt geared 1:1.8 so I get 5400 rpm at the spindle. My goal was higher spindle speed and being able to do rigid tapping. Both were achieved.

DMM-DYN4 1.8kw

Attachments:

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18 Aug 2020 06:14 #178569 by BeagleBrainz
Replied by BeagleBrainz on topic Spindle Motor Advice
I opted for the 750 watt from DMM, the local supplier never got back to me, could be something to do with the hipsters in Melbourne and the beverage plague.

Was going to go thru one major US supplier but they were $110 USD more for delivery than DMM.

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18 Aug 2020 11:25 #178595 by BeagleBrainz
Replied by BeagleBrainz on topic Spindle Motor Advice
Johnny have you any tips for setting up the DYN4 as a spindle.
I'd guess I'll also need a 7i83 for the analogue voltage to control the DNY4.

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20 Aug 2020 03:14 - 20 Aug 2020 03:15 #178790 by JohnnyCNC
Replied by JohnnyCNC on topic Spindle Motor Advice
I'm using a 6l25+7i76 and I did add a 7i83 for the 0-10v interface. I used the AB encoder signals sent out by the DMM drive and I added a slot type optical sensor on the spindle for the Z signal. I had to do that because of the 1:1.8 toothed belt gearing. You can probably use 1:1 gearing since the max speed on the 750 watt is 5000 rpm. On the 1.8kw it is only 3000 rpm and I could afford to trade some torque for speed.

The other thing that the docs or the tech warned about (can't remember which) was not to do quick power cycles like off then right back on again. I think I put something in the HAL to prevent that from happening but I would have to look.

This was some advice I got from DMM Tech support:

For use as spindle motor, set Integration Gain to "1" and keep it at "1". Then increase Main Gain and Speed Gain until the motion is rigid and suitable. Keep Main Gain and Speed Gain at the same value.

Make sure to install a regenerative resistor on the drive to help absorb deceleration energy from the motor. Also install a transformer or AC line reactor on the AC power input to smooth and filter the power coming into the drive.

We have a large regenerative resistor for $62 with attached specifications. The line reactor you can use something like this unit: www.automationdirect.com/adc/Shopping/Ca...ine_Reactors/LR-23P0


These are the settings I ended up with:
Attachments:
Last edit: 20 Aug 2020 03:15 by JohnnyCNC.

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28 Aug 2020 07:42 #179792 by BeagleBrainz
Replied by BeagleBrainz on topic Spindle Motor Advice
Cheers mate, sorry I missed your reply. Just received my servo & driver package this week, had a bit of a play around on the bench using the DMM software.
Have a 7i74 & 7i83 on order as well as some noise filters. Just need to get a contactor with a 24v DC coil and a line reactor. The joys of living Down & Under, throw the covid thing in and it's almost impossible to buy stuff. "Stock is due in but........."
Good info on the on\off power cycles.
High speed gearing with the kit I got is 1:1 so max speed should be about 5k less whatever losses in the system. The lower gear is 1:0.647. Most of the stuff I work with is mild steel so the lower speeds should be good.
This weekend's plan is to make a replacement motor plate as the one I was supplied with the belt drive kit is for the std g0704 motor.
If it's ok I may ask about your HAL setup for the spindle just to have a base to start with.

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30 Aug 2020 00:14 #179985 by JohnnyCNC
Replied by JohnnyCNC on topic Spindle Motor Advice
Attached are all of my .ini & .hal files that involve the spindle operation.

Warning: Spoiler!


Warning: Spoiler!


vc-p4s.hal
Warning: Spoiler!


vc-posthui.hal
Warning: Spoiler!
The following user(s) said Thank You: BeagleBrainz

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30 Aug 2020 00:19 #179986 by JohnnyCNC
Replied by JohnnyCNC on topic Spindle Motor Advice
Check out the 3hp BT30 spindle that Clough42 on youtube just put on his G0704. If I was upgrading now I would use the one he got. It is sweet!

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