Re: Converter or Inverter for 2hp Bridgeport mill

I used a toshiba single phase in, 3 phase out inverter. I used the
bridgeport relay to turn on with dry contacts, left the overload in
place (overkill since inverter monitors too). I gutted the cnc drives
and upgraded at that time too thou. Inverter works great.

My phase convertor made the head rattle, inverter is much smoother.
Money well spent. I have my machine on a 30 amp 220 single phase
circuit now. Like I said I upgraded the cnc drives too. The 3 phase
cnc drive transformer had to go.

David Cofer




--- In CAD_CAM_EDM_DRO@yahoogroups.com, "john_glynn57"
<john_glynn57@y...> wrote:

> I have just taken delivery of my own Bridgeport mill and want to
> know which is the best option for powering the machine : an inverter
> or a converter.
> My research to date suggests that a Hitachi L100 inverter is the way
> to go however I want to question this as follows:
> 1. I can run a dedicated 20A or 30A supply to the machine which
> should be able to handle the startup current demand of a converter.
> 2. If I use a converter I can use all the original Bridgeport
> systems without mosification ie Bridgeport speed control,forward and
> reverse,3phase coolant pump and shaping unit which is attached to
> the machine.
>
> My plan is to circumvent the original Bridgeport wiring and drive
> the Main motor(s) directly from the hitachi unit and setting the
> motor speed at the low speed of 1400 and not using the valiable
> speed control of the machine at all. The hitachi will give me speed
> control by varying the frequency however I do intend to use the
> original forward reverse switch. In addition I plan to replace the
> coolant motor with a single phase model.
>
> Am I doing the right thing.