Re: [CAD_CAM_EDM_DRO] Bridgeport conversion

Hi Robin,

I used Geckos on mine for a while. The motors worked best on 75V (rewire
the original main 110V transformer to give 55VAC out) and only using 2
of the 4 windings on the motors. I had two main problems with this setup:

Two Geckos went up in smoke on my Z axis. X and Y had brand new drives
which worked fine. I used some quite old Geckos on the Z so there may
have been a design change somewhere along the line.

Lost steps. Looking back on it, this may have been a problem with Mach2
rather than the drives. As you know M2 pulsing can be a bit uneven at
times. As BridgePorts are very heavy, acceleration is critical.

In the end I junked the steppers, put the Geckos back on my plasma and
converted to servos. A huge improvement!

Les

rszemeti wrote:

>Hi,
>
>I have a bridgeport Interact series 1 CNC mill, with steppers, that I
>want to convert form its ancient "boss 5" cnc control, to something newer.
>
>The question is, should I keep the old stepper drives, or fit geckos?
>The drives on the older bridgeports take "phase" rather than step and
>direction input, which thankfully EMC is quite capable of providing
>... so no problems there. The only issue is are Geckos up to the job
>(thes motors draw 7.5 amps, thats 3.75A per winding as they are always
>driven "two-coil" fullstep with a bipolar drive.
>
>Should I stick with the old drives or will geckos give me a
>performance increase?? The old drives certainly powered the steppers
>before, but with their "saturable inductors" .. I wonder how much
>improvement I'll see with a modern drive? The motors are 8 lead, so it
>should be possible to wire them up to work nicely on a gecko ...
>
>This must have been doen before .. whats the score??
>
>
>

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