On 2011-05-21, meatwad wrote:
responding to
http://www.rittercnc.com/metalworkin...e4-429295-.htm
meatwad wrote:
Hi Lloyd,
I have no idea if you will get this email, but I though I would give
it a try. *I just purchased a bridgeport r2e4 boss 9 mill, and moved
it into my garage workshop. *I plan to convert it over to mach3, emc2
or centroid control, but in the meantime it would be nice to see if it
actually works. *Rather than buy/build a RPC, it would be nice to just
convert the control over to single phase 230. *can you elaborate on
how you changed your machine over to single phase?
Hmm ... the BOSS-9 is one of the servo machines, is it not?
You've got a better chance than I did with the BOSS-3, which is
stepper motors, and has a big three-phase transformer from the secondary
of which each phase provides the power to a single stepper and its
drivers. Add to that a saturable reactor (also called a MagAmp) between
the secondary and the bridge rectifier for the stepper motor's power
supply to adjust the voltage -- something like 50 VDC or so when the motor
is stopped, or being stepped slowly, and 80 VDC when the step rate goes
up. This is because the maximum step rate is limited by the inductance
of the stepper windings, but at the 80 VDC, the current overheats the
steppers when they are *not* being stepped rapidly.
Anyway this does not gracefully accept the variable frequency
of a VFD. And it is also rather difficult to re-wire to single phase
power.
The actual computer part (a DEC LSI-11 CPU and a bunch of custom
electronics to go with it) is powered from a single phase, so it is no
real problem -- only the individual stepper motor power supplies.
So -- expect yours to be a lot easier to fix up. From what you
quoted and I trimmed, I gather that the two phases used to power it were
selected to minimize the total current drain from a single phase.
Of course, you will need a VFD or a RPC to handle the spindle
motor, which *must* have three phase to work properly.
Good Luck,
DoN.
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