Centroid Community CNC Support Forum

Personally I'd ditch the DC motors too. Every time Ive tried to retain the DC motors on a conversion Ive had some or other issue ....

Go AC servo, dont look back.

Likely a smaller machine than yours (Bridgeport Interact 1), this was done with 750W Panasonic servos, 6 years ago now ...

You can use Delta B3A-xxxx-E models with Acorn. They have step and direction inputs on the control header. I do not believe we have a schematic for this yet but you can get some guidance with the wiring and configuration from this post viewtopic.php?p=95584#p95584

If you eventually decide to change to Hickory, the drives will only require a few parameter changes.

Some more info on machine
Servo with name plate Spindle motor I've searched the page and YouTube
Has anyone used the szgh or licuan servos off alibaba ?
They both offer ethercat and standard step,directions whether they are any good might be another whole factor as to why I can't find much on them

SZGH will not work with Hickory at this time. We do not recommend Lichuan for Hickory use at this time. Either manufacturer should have something that works with Acorn. We typically recommend Leadshine for low cost servos because they have good tuning and configuration software.

To match original performance, you'll want servos with at least 4.5 Nm rated (stall) torque, 4000 RPM max speed, max/peak torque of at least 22 Nm, and inertia of 0.0023 kg*m^2.

If you were looking at Delta B3A and assuming 200-240V service, I would recommend using either ECM-B3H-FA1313 or ECM-B3H-FA1318 to replace those SEM MT30U4-36 motors. The 1300 watt model matches torque and speed but has less inertia than the DC motors. The 1800 watt motor will be a better match for the inertia of the original SEM motors.

My bed mill has very similar Jin-Shin 5hp motor and SEM servos. I went with Clearpath all in one (servo, encoder, drive) AC servos.

CPM-SDHP-N0563P-ELS
Torque Continuous 71 lb-in (8.1Nm
Torque Peak 290 lb-in 32.9Nm
Watts/HP Continuous 1876W/2.52hp
Watts/HP Peak 5,769W/7.74hp
Max speed - 2,760 rpm

Notes

1. The diameter of the Clearpath AC servos are significantly larger than the SEM's. The SEM mounting plates are too small. Z and X fit in the physical space the SEM's occupied but Y does not. The Y SEM is turned around backwards and buried up inside the base casting with the pulley sticking out. The hole in the front of the casting is too small for the Clearpath. It's nasty up in there so I'm not too bothered by having to relocate the Y servo to outside the casting.

2. My SEM's were max 3,000 rpm vs your 4,000 rpm but oddly rapids were dialed back to 300ipm X and Y and 200 imp Z in any case. The Clearpath are a max RPM of 2,760 but can still yield rapids well in excess of the factory spec 300/200 imp. X and Y are 1 to 1 ratio pulleys, Z is 2 to 1.

3. I could not get a clear answer from Clearpath on amp draw. They ended up giving me the max amp draw for 1ph when I asked for 3ph so I ended up buying a larger RPC than was required. But the price difference between the 10hp and 15hp RPC American Rotary was marginal so I'm not unhappy with the extra capacity.

centroid467 wrote: ↑Wed Mar 19, 2025 9:31 am
To match original performance, you'll want servos with at least 4.5 Nm rated (stall) torque, 4000 RPM max speed

I'd be curious to know what the factory configured rapids are. My SEM's are rated 3000 RPM max. With the 5mm ball screw pitch, at 3,000 rpm that's 590 ipm for X and Y, and 295 ipm for Z with it's 2 to 1 pulley reduction. But the mill was configured for max rapids of 300 ipm X and Y and 200 IPM for Z well below what the servos were capable of at max rpm.

The good news is this opened up some servo options with slower max RPM. The 2,760 max RPM Clearpaths while slower than the original SEM max 3,000 rpm servos, they can still significantly exceed the factory configures max rapids.

Stansonengineering wrote: ↑Wed Mar 19, 2025 7:31 am Some more info on machine
Servo with name plate
IMG20250319130652.jpg
Spindle motor
IMG20250319130825.jpg

I've searched the page and YouTube
Has anyone used the szgh or licuan servos off alibaba ?
They both offer ethercat and standard step,directions whether they are any good might be another whole factor as to why I can't find much on them

these axis motors you have are a slam dunk with the Allin1DC.

https://goo.gl/photos/MEmLM5ui1NeuUkG37

https://www.centroidcnc.com/sem_dc_serv ... rofit.html

https://shopcentroidcnc.com/shop/custom ... nd-others/

cnckeith wrote: ↑Wed Mar 19, 2025 5:07 pm

Stansonengineering wrote: ↑Wed Mar 19, 2025 7:31 am Some more info on machine
Servo with name plate
IMG20250319130652.jpg
Spindle motor
IMG20250319130825.jpg

I've searched the page and YouTube
Has anyone used the szgh or licuan servos off alibaba ?
They both offer ethercat and standard step,directions whether they are any good might be another whole factor as to why I can't find much on them

these axis motors you have are a slam dunk with the Allin1DC.

https://goo.gl/photos/MEmLM5ui1NeuUkG37

https://www.centroidcnc.com/sem_dc_serv ... rofit.html

https://shopcentroidcnc.com/shop/custom ... nd-others/

It would save alot of work to make 130 frame servos fit in their place as they still work well.
My one concern is I can't find anywhere on the website that states the all in 1 DC can run more than 3 axis ?
Can additional axis be added for 4-5axis upgrades ?
Ideally in AC servo so I could buy a drive and motor for a 4th axis down the track ?

ALLIN1DC can control up to six axes but only has three DC servo drives built in. The standard way to add more drives to ALLIN1DC is to use the DC1 (https://shopcentroidcnc.com/shop/cnc-ex ... oards/dc1/).

Adding AC drives may be possible but I do not believe we support that configuration.