Re: bridgeport series 1 retrofit

MY 1976 series One bridgeport boss 6 cnc, it had a 3 phase controls
transformer for the Nema 42 stepper motors. I tried every way to wire
the transformer and the common metal armature crosstalked to the
voltages on the transformer. I had heard of people cutting them in two
between the windings so I tried that. I slipped with the saw and had
to purchase a new 48va (dual 24) transformer which I mounted in the panel.

I started out with geckos, Now I have Larken drives putting 8 amps
to the motors. They do not have the steps per rev the geckos had, but
work excellent.

I also put in a single phase in, 3 phase out inverter for the head.
I think I had a little over 1200 in my conversion. Using Qstep
software at $65. A 2.4 bare bones intel machine. I now have several
packages on it and don't know which one I like the best.

I did drawings, have bridgeport boss drawings now, it was a disaster
when I UNWIRED it. I tried to decipher it from pulling wires and
drawing schematics. I spent about a week on a creeper pulling wires.

The end result works great and I am adding the extra axis to the indexer.

David Cofer, North georgia, Tunnel Hill ...

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "jlsmith269" <jlsmith269@y...>
wrote:

> I am also contemplating the sample conversion, with a series II rather
> than a series I, for lighter weight work than the machines are
> designed for. I can not forsee me EVER having a workpiece over 100#,
> as I would be making things like gunparts and ATV parts. I am also
> planning on a dividing head/4th axis for making octagon barrels and/or
> other neat things.
>
> I thought that the series II probably has servo motors.
>
> I am a complete neophyte on this stuff, so feel free to correct me.
>
> my tenative plan is
> 1: reuse bp servo motors (if they are servos)
> if not, please suggest motors and encoders
>
> 2: use the BP Powersupply for running the motors, and use the gecko's
> for controlling the servos (right? or am I totally missing external vs
> internal to gecko drives)
>
> 3: use existing leadscrews on the BP and have the software correct for
> backlash. the 1600 bucks for ball screws is just too much.
>
>
> 4: use something like EMC or ramsoft for the PC software.
>
> what do you think? Am I totally off base?
>
> Since the BP II's are going for ~1000-1500 on ebay, if i don't buy
> motors (500 each plus mounting hassles) and don't buy leadscrews
> (1600) I think this can be done, including rotary phase convertor, for
> 1500 over the cost of the BP, or less
>
> jeffe
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, Robin Szemeti <list@r...>
> wrote:
> > On Thursday 08 January 2004 22:19, Bob Japundza wrote:
> >
> > > 1. Stupid question: how can I determine if my motors are capable
> of
> > > microstepping? This will obviously determine my choice of drives
> > > between the G201 or the G210.
> >
> > umm not really ... the G201 and G210 both produce a microstepped
> output, the
> > G210 simply has a 'pulse multiplier' on the step pin. Your motors
> will be
> > fine with either. If I was intending to run on EMC I wuold chose
> the 210's
> > myself, especially if running on a older PC. they give you a
> little more
> > flexibility in pulse rates that may help in certian circumstances.
> >
> > there are lots of 'bridgeport specific' bits in EMC, it will work a
> treat.
> >
> > > 2. Would a 77vdc power supply with some large caps on the output
> > > sufficiently filter out ripple and not damage the Gecko's? I'm
> > > concerned that my power supply may be a wee bit too close to the
> 80v
> > > rating for the Gecko's.
> >
> > I'd drop that to half voltage by fiddling the tappings if you can...
> 40V is
> > more than sufficient in general .. there seems to be a 'as many
> volts as
> > possible' theory that comes from somewhere, that leads to nothing
> other than
> > hot drives and hot motors .. 80V is pushing it a bit I think ...
> esp. onhte
> > day when the mains goes a bit high ....
> >
> > > 2. Is it possible to use EMC (or any other cnc package for the
> > > matter) to drive steppers with a DRO serving as a closed-loop
> > > system?
> >
> > EMC at one stage in time had support for the mauch/kaluga DRO card.
> its still
> > there in the codebase AFAIK
> >
> > > Some of the DRO's I've looked at have a RS-232 output, and
> > > am wondering if there's a 'standard' for DRO outputs so they could
> > > be integrated in a closed-loop system. I'm thinking of building
> one
> > > of Scott Shumate's DRO-350's.
> >
> > it is extremely unlikely that you could use a serial DRO system in a
> servo
> > control loop ... the main problem is the inevitable delays of the
> serial link
> > reducing the phase margin of the loop. Oscillation is almost
> guarenteed I
> > would imagine.
> >
> > However ... you'll find the leadscrew and backlash compensation in
> EMC can
> > map the leadcrews of a bridgeport every inch or so, and differently
> in both
> > directions to take account of wear so it should come out pretty much
> spot on.
> > The DRO's are very helpful in setting this up.
> >
> > > Any help would be greatly appreciated.
> >
> > call in on the EMC users list on Sourceforge or on IRC:
> >
> > server: irc.freenode.net
> > channel: #emc
> >
> > always some people on ..
> >
> > --
> > Redpoint Consulting Limited
> >
> > Real Solutions for a Virtual World
> > http://www.redpoint.org.uk