Re: [CAD_CAM_EDM_DRO] Re: Bridgeport 440 volts to 220 volts.

I've got a whole 440V electrical panel here for stripping, including a
440V 3 phase variable frequency drive, 440 "heaters", 440 v contactors,
etc. Let me know what you need and I may be able to help.

Kim

On Fri, 2003-11-21 at 17:27, vavaroutsos wrote:
> Gary, what tye of CNC is this? Is it a BOSS 6 or older? If so, the
> heater is in the large power enclosure on the rear of the machine. It
> is separate from the contactor and mounted next to it in the upper
> part of the enclosure. However, it's an old Sylvania part that is
> hard/expensive to get. If you're not going to be running the machine
> hard, just short the heater out until you retrofit the machine (you
> will want to after you use the BOSS control).
>
> I converted my BOSS 6 from 440V to 220V by changing the wiring on the
> main stepper transformer and the 110V transformer. Don't worry about
> the fuses unless your going to run the machine really hard. I have
> not had any problems and did not change the fuses. If you don't short
> the heater or change it, it will trip after running the spindle for
> several minutes.
>
> ~petev
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "cncgramps" <cncgramps@y...>
> wrote:
> > Jeff,
> >
> > Thanks for the reply.
> > I am starting to think it might be easier to replace the switch.
> > Mine has the high/low switch plus it has the emergency stop switch.
> > Bridgeport manual says the heaters are in the switch box and are
> > very hard to get at. I have looked and you can not see the typical
> > coil type overload heaters.
> >
> > Thanks
> >
> > Gary
> >
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "washcomp" <jeff@w...>
> wrote:
> > > Gary:
> > >
> > > The motor starter is sometimes called the contactor. It is
> > > sometimes combined with a safety switch (combination starter).
> > The
> > > three things you look for:
> > >
> > > 1) The heaters (overloads) will be pretty ovbious to any
> > > electrician with motor experience. If you contact the
> > manufacturer
> > > of the starter, they can help you locate the heaters. Depending
> > on
> > > the vintage of the starter, they may look like a losenge with a
> > > number on them or may look like a spring. They will break the
> > coil
> > > circuit if they are overloaded.
> > >
> > > 2) Check the coil voltage of the starter. If your tool uses
> high
> > > voltage control, the coil may be 440v and have to be changed.
> > >
> > > 3) Check the current rating of the starter. The motor will draw
> > > about twice as much current at the lower voltage. Since starters
> > > are sized by current, if yours was marginal at 440 volts, you may
> > > need to change the starter.
> > >
> > > Regards,
> > > Jeff
> > >
> > > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "cncgramps"
> > <cncgramps@y...>
> > > wrote:
> > > > --- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...>
> > > wrote:
> > > > >
> > > > >
> > > > > cncgramps wrote:
> > > > >
> > > > > >I am about to hook up a Bridgeport Series 1 CNC that is
> wired
> > > for
> > > > > >440. I have the manuals and it shows and tells how to change
> > to
> > > > 220
> > > > > >which I need to do.
> > > > > > The part that I am in question about is the overload
> heaters
> > > > that
> > > > > >are in the switch. The manual says they are hard to get at
> > and
> > > > that
> > > > > >they recommend getting a new switch wired for 220.
> > > > > > I looked in the switch box and I can not see the typical
> > > heaters.
> > > > > >Has anyone ever changed those overload heaters out so as to
> > be
> > > > able
> > > > > >to run on 220 volts?
> > > > > >
> > > > > >
> > > > > You just have the little 2 x 2 x 4" drum reversing switch on
> > the
> > > > motor?
> > > > > That has no heaters. The heaters would be in a device called
> > > > a "motor
> > > > > starter" and usually are mounted right on one of the
> > > contactors.
> > > > These
> > > > > break the control circuit if the heaters get too hot,
> > indicating
> > > > the
> > > > > motor is drawing too much current on at least one phase.
> That
> > > way,
> > > > > they protect the motor from overload, single phase operation
> or
> > > > > internal shorts.
> > > > >
> > > > > If there are contactors in the motor box, one of them should
> > have
> > > > > heaters on it. They may be quite small, like little
> > cartridges
> > > > that
> > > > > plug in. You will need to change them, as the current draw
> on
> > > 220
> > > > > will be twice as high, and will cause the spindle to shut
> down
> > > very
> > > > > easily.
> > > > >
> > > > > Jon
> > > >
> > > > No mine has a large box with a forward reverse "hi/low" switch
> > > plus
> > > > an emergency switch.
> > > > The manual talks about the heaters being in the main switch
> box
> > > for
> > > > the motor and being hard to get at. Thus the reason for
> > replacing
> > > > the switch.
> > > >
> > > > Gary
>
>
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