Re: Converter or Inverter for 2hp Bridgeport mill

VFD's are great!!
I think most VFD's have reversing builtin(?). Having a switch break
connections from the VFD to the motor doens't sound good to me. If
you want to keep the mechanics of the original Fwd/Rev switch, I
would suggest wiring it as a switch to control the VFD's external
fwd/rev option if it can be done as an external control.

-Lee JMO-ICBW:-)





--- 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.