Re: what will i damage?..running 220 1ph into220 3phase transformer?

I did not have success with gecko drives on my bridgeport. IF YOU do run
them make sure to heat sink them with a fan. I lost 4 total... Larken Cobra
drives are much more suited to the Nema 42 motors and I run mine at 8 amps
and get 110 ipm out of it. NEVER could I get that speed from a gecko on the
system without losing steps. DON'T get me wrong, geckos are fine drives
just a nema 42 stepper is on the upper thresh hold of the drive... USE
maximum precautions with heat and current voltages.. That heavy slide will
generate enough decell-inertia related voltage to kill them drives also. If you
limit the current to 6.5 amps and keep them drives cool you might be able to
run 30-40 ipm... IF anyone is running faster then this with this setup I want to
see it. Look to lose steps under heavy cuts with this setup.

Someone on another board equated this to running a YUGO motor in a
corvette. Made fun of me for even trying out geckos on my mill..

I rewired the taps on the 3 banks of stepper transformers about ten or more
times trying to find something that would work with single phase, I didn't.
They need to be seperated cause the 3rd coil on the common armature will
affect it.. YOU could try using two of the coils on the bank and ignore the
third, not sure what that'd do.. I kept ending up with a odd voltage on the 3rd
coil.. I have heard of people cutting the armature in between the coils and
they work fine..

I replaced the transformer bank with a 2kva 220/24+24=48vac transformer.
Still running fine with Larken drives and that setup.. I have lost a bridge
rectifier. Seems not all of them are as good as some of them. Current model
is a 35 amp IOR 600 volt. I have 4 100amp stud mount diodes mounted and
ready if I have another bridge go out..

Lots of good parts inside that boss setup to reuse. Them capacitors are
great. Terminal strips, 220/120 transformer, 24 volt system switches and
other goodies..

I had pictures posted on the net of my machine, but I deleted them to make
room for some ebay items. I can repost them next week probably if you'd like
to see how I skinned a cat. There is more than one way you know..

I think if I had it to do over, I'd run 5:1 servo motors on my mill/ Rutex drives
and the rest the same.. GUT it all and sell the steppers on ebay.. *I did throw
about six hundred pounds of old boss junk into a box and ship it to a happy
ebayer who runs original hardware..

David



--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Mike Mueller"
<mueller914@y...> wrote:

> Bridgeport Series 1 w/Boss 3 controller:
>
> looking at the main electrical box, I wired up power going to only 2 of the 3

main fuses as follows:

> (left to right)
>
> left= hot
> middle= hot
> right= no connection or power
> (yes, machine is grounded)
>
> The three transformers for the steppers read 53vdc, i can feel that the

stepper motors get energized. The controller does not work, which is fine
since it's being removed as the Bridgeport will be operated via my PC and
G201's.

>
> Am I asking for trouble running it this way?
> VFD is going to run the spindle motor.
>
> Thanks,
>
> Mike