Re: BOSS5 to Mach2/Gecko

Hi, I am also doing a bridgeport retrofit and am using
steppers...Your post was very interisting, and i have a few questions
about it...

1. Are your steppers directly driving the screw or are you using a 2
to 1 belt reduction drive.

2. Are you using the Gecko G201 or the G210. And how are you
driving the inputs to these drives. Full step, half step or micro
step.


Wally





--- In CAD_CAM_EDM_DRO@yahoogroups.com, "ja_erickson"
<ja_erickson@y...> wrote:

>
> Evening All,
>
> I have been doing my Boss5 retrofit project for some time now and
> have done exactly what you want to do with the exception of the

power

> supplies. i built my own 72 volt/7 amp toroidal power supplies and
> used gecko g210's with pretty good results. I rewired the original
> bridgeport steppers to run in "half winding" which will provided

more

> low speed torque. according to my bridgeport manuals the original
> steppers were designed for 68 volts and 6.8 amps which is right on

the

> upper side for the geckos. I was concerned about it until i spoke

to

> the owner of gecko drives and he assured me that 72 volts and 7 amps
> would be alright for the 201/210 series. he also warned that it

would

> be WISE to incorporate a "return energy dump circuit" in order
> to protect the drive against any "returned energy" from the motors
> during sudden stops.neither the drives or the motors ran hot so

fans

> for the drives were not needed.the campbell breakout board is a

must

> have item becuase it really provides alot of interfacing in a
> relatively small footprint, well worth the cost. motor tuning with
> mach2 went really smooth, just dont expect the machine to move like

a

> new c.n.c., the machine would lose steps if the accelerations were

to

> great and i think i could achieve 60-80 i.p.m. reliably.however

there

> was a problem with the system in the end where any feedrates below 4
> i.p.m. were very steppy, by this i mean you could put your hand on
> the table and actually feel the motors step. i couldnt have that
> because i was afraid of tool marks on the workpiece. i talked with
> the owner of gecko drives and he helped me all he could to rectify
> that situation but we couldnt get rid of that steppiness. if that
> situation doesnt bother you then i wouldnt hesitate to retro it.
>
> Jeff