Bridgeport Boss5 to Centroid Acorn retrofit

All things related to the Centroid Acorn CNC Controller

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Tapburrbit
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Bridgeport Boss5 to Centroid Acorn retrofit

Post by Tapburrbit » Fri Jan 05, 2018 9:07 am

Hi All , I'm New here today and received my Acorn board yesterday . Still waiting on the computer I will be using. I expect it any day now. I going to retrofit a Bridgeport Boss 5 . I plan on keeping the original superior stepper motors .

I am seriously considering using the Leadshine DMA860E Drive. It seems Ideal for my application .

To me it makes sense to keep Bridgeport's main 3 phase T2 transformer, it can be tapped for 60 , 70 or 80 vac . Currently it's tapped at the 60 vac which is putting out 56vac to run the original superior steppers thru the huge original dc power supply drives that have got to go !

From what I understand if I put 56vac into the DMA860E I can get up to 78vdc to the motors at 7.2 amps .

Am I doing the right thing ? this is my first retrofit . I've been considering do this for years and after stumbling upon this acorn board that runs on Centriods control software ,It's finally the time. If it works out I will eventually do the other 2 machines I have.

Thanks, David
Last edited by Tapburrbit on Thu Jan 18, 2018 7:59 pm, edited 2 times in total.

toolmaker101
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Re: Bridgeport Boss5 to Centroid Acorn retrofit

Post by toolmaker101 » Fri Jan 05, 2018 9:13 am

Have you tried searching on the forum for Boss5. I have only been on this forum a few weeks and have seen lots of info on Bridgeport machines.

pulsenpal
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Re: Bridgeport Boss5 to Centroid Acorn retrofit

Post by pulsenpal » Fri Jan 05, 2018 2:08 pm

Bridgeport Boss machines 3,4 5 and 6 used either superior or sigma step motors
around 1100 oz inch holding torque

the step motors were all 8 wire configured but BP had a unique method of center tap in each
of the two opposing windings to create a 5 wire input which was neither series or parallel
but somewhat of a hybrid

remove the endcap from stepper and you will find 6 wires --when you connect to leadshine drive only 4 wires per stepper are used

I recommend wiring series for maximum torque on these 35+ year old axis motors

the Boss machines had a mains transformer with multiple taps allowing input 3 phase power from 200 to 600 vac

if your input power for planned retofit is single phase I suggest complete bypass of the three phase transformer
each of the 3 step motors had a voltage reducing transformer which reduced ac voltage to 48-50 vac which was then routed to
control cabinet on left side of machine and rectified to 56-60 vdc for distribution to step motor

if you are powering Boss with 220 vac mains single phase - a single stepdown transformer of 1.2 kilowatt is usually sufficient to supply all 3 Leadshine drives with ac power you will need buffer electrolytic capacitors fuses etc as directed
I recommend no greater than 70 vac input into Leadshine drive--dc output from Leadshine to each stepper will be 85 or so vdc-- somewhat higher than original Boss from factory

the 3 phase spindle motor should be powered by a variable frequency drive single phase input-- this will eleminate need for the 3 phase mains transformer in the BP cabinet--a very power hungry device

when you complete retrofit your power consumption will be about 20% of original Boss 5 configuration

use ohm meter to puzzle out winding configuration of superior stepper--and lots of referrence is online

jh
Attachments
uou8ou.JPG

Tapburrbit
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Re: Bridgeport Boss5 to Centroid Acorn retrofit

Post by Tapburrbit » Wed Jan 17, 2018 9:13 pm

Thanks for the reply's . Sorry for the delay , I just noticed them.

To answer toolmaker101 . I have been looking at other forums on and off for years. There is lot of info available and too many different ways of doing it. Making the choice and time commitment to start the project has always been stopping me until now.

Pulsenpal , Thank you for your info. I did buy the dma860E drives and I do plan on keeping the machine a 3 phase machine. I've removed the computer , it's power supply and large DC power supply also . I plan on keeping the T1 (110ac) transformer to run the new 24vdc and the 5vdc supply for the acorn and dma860E and an additional 24vdc to run any larger relays, coolant , speed up down ,etc.

You mention the 3 step down transformers , those must be the SX1 ,Sx2 , Sx3 . just below the 3 phase transformer. I've removed them. I didn't think I needed them.
The T2 the 3 phase transformer steps the ac power down to 60 , 70 or 80 vac. I plan on just tapping into it for the drives. Each would be on it's own phase. I plan on putting a fuse in between , should I also put a capacitor? if so where can I find the info for wiring that in properly?

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Re: Bridgeport Boss5 to Centroid Acorn retrofit

Post by cnckeith » Wed Jan 17, 2018 10:23 pm

a cool way to make DC power for stepper drives (or DC servo drives or AC servo drives that need DC input like DMM DYN2) from AC power is with Centroid's cap and bridge combo. just put AC in one side and smooth DC comes out the other at a 1.41 multiplier.
available our the website here.. http://www.centroidcnc.com/centroid_diy ... nents.html
bridge cap.JPG

Tapburrbit
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Re: Bridgeport Boss5 to Centroid Acorn retrofit

Post by Tapburrbit » Thu Jan 18, 2018 4:03 pm

I have been planing on feeding the DMA860E drives with 56 Vac from the T2 transformer. I guess I could give them DC they are supposed to accept both. The T2 is taking in 208 vac 3 phase and can be tapped 56vac, 64vac or 74vac. Attached here's a picture of the transformer and the bridgeport original schematic .
terminal 5 to 6 reads 56Vac
terminal 5 to 7 reads 64Vac
terminal 5 to 10 reads 74Vac
T2 _diagram.JPG
T2_IMG.JPG

I'm having doubt about hooking this transformer up to the leadshine drives now. It only shows voltage between the terminals I mentioned above . It shows no voltage between the the terminals and ground or the neutral side of the T1 transformer ( input to the T1 is 220vac and it outputs 110 and a neutral to ground)
Last edited by Tapburrbit on Thu Jan 18, 2018 8:22 pm, edited 1 time in total.

pulsenpal
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Re: Bridgeport Boss5 to Centroid Acorn retrofit

Post by pulsenpal » Thu Jan 18, 2018 8:04 pm

if you have balanced 3 phase input power --not static or rotary convertor--
you may be able to tap off main transformer to supply voltage range 50 to 70 vac

I have not used leadshine drives, but most comparable drives have electrolytic capacitors board mounted--
this gets you around building stand alone dc power supply since leadshine accepts both vac and vdc input

many older drives required only dc input from unregulated power supply--using ac input power simplifies
installation and reduces component count

I agree with removal of other components you mentioned

Cnc Keith is the guru on all things Centroid--they provide great products

Tapburrbit
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Re: Bridgeport Boss5 to Centroid Acorn retrofit

Post by Tapburrbit » Thu Jan 18, 2018 8:26 pm

I just updated my previous post with this . I am a little afraid of putting ac power into the drive with out a neutral ?

I'm having doubt about hooking this transformer up to the leadshine drives now. It only shows voltage between the terminals I mentioned above . It shows no voltage between the the terminals and ground or the neutral side of the T1 transformer ( input to the T1 is 220vac and it outputs 110 and a neutral to ground)

pulsenpal
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Re: Bridgeport Boss5 to Centroid Acorn retrofit

Post by pulsenpal » Thu Jan 18, 2018 11:17 pm

the primary 3 phase transformer may present a problem regarding neutral/ground

I have used the single phase step down transformer located in lower right of transformer cabinet
to power step motor retrofit drives--this was 20 years ago and details are fuzzy--in those days only dc voltage input
was the choice for powering lower voltage drives

recall around a 1.25 kw transformer output--this will nicely supply the superior or sigma steppers
the Boss machines shipped with

post a pic of the single phase transformer and describe what the build plate reads--neutral ground on this transformer is no problem usually

Tapburrbit
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Re: Bridgeport Boss5 to Centroid Acorn retrofit

Post by Tapburrbit » Fri Jan 19, 2018 10:39 am

The T1 Transformer has no identification plate on it , stenciled on it is Milw . Trans. Co. C1-53231 . see photo and schematics from BPT manual.

It's feed by 2 hot legs , H1 by leg 1L1 and H4 leg 1L2 , output X1 is 110Vac ( wire labeled x1 which becomes 3 after a fuse) and output X2 is a neutral ( wire labeled 2) and ground going to chassis ground.

It's labeled to be a 1KVA transformer on the schematic. I think that's 9-10 amps at 110V . I think fine for powering the fans , 24vdc and 5vdc power supplies. Originally It looks to me that it also powered transformer T6 ( 56V) that was in the power supply on the side of the machine where it was rectified. That power was then very confusingly to me tied into the T1 3phase transformer and the (SX1, SX2 ,SX3) transformers also rectified there. The main reason I'm doing this conversion is to get rid of those rectifiers. They were stuffed way back there difficult to get to. What a pain they are to change.
Attachments
T1_IMG.JPG
T1 _diagram_2.JPG
T1 _diagram_1.JPG

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