Re: [CAD_CAM_EDM_DRO] Re: Harrison Lathe and Gecko's

Hi Doug,

Thank you for your suggestions below. My machine is three-phase and I don't
want to go down the route of tinkering with it unless I decide to do a
complete retrofit. I can't afford the time to do this at the moment because
there is a job waiting. The machine has all the functions of a CNC lathe on
the front panel and most of this works fine.

The power supplies are many with four different transformers. The one that
we are concerned with here only feeds the stepper motors. The transformer
has two outputs of 61 volts AC @ 20 amps and also a 19 volt AC @ 5 amp (I
think this is to feed the logic on the drives because they appear to have
switch-mode supplies). The input side of the transformer is tapped for
various voltage supplies. 220, 240, 415, 440. I have a three-phase supply @
415 volts if I used the tap @ 440 instead of the 415 wouldn't this reduce
the output voltage enough to use the Gecko's without affecting the other
driver too much.

As the supply for both steppers is fused @ 10 amp I wouldn't have thought
the Z motor needs more than 6 amps, but I'm checking the motor
specifications with the manufacturer tomorrow.

I was hoping to use Gecko's because Mariss gives so much help on this list,
there are probably other drivers that could be used. Although with the curt
reply to my post I'm not so sure now.

Regards,

Terry

> Hi James:
>
> I make 1KW 75VDC power supply kits (specially for the 80VDC max Geckos).
> The toroid is qualified for 50 Hz & 240VAC, as I expect you have in

Britain.

>
> If you have stepper motors on your Harrison (we have a Harrison, but alas
> it is only manual!), what are the voltage & current ratings on it? (I

expect

> around 4-10VDC & 3-6 amps range)... in which case the G201/G210 will work

fine

> (as long as your motors are 2 phase input steppers).
>
> I am taking delivery of my third cnc lathe (with blown controls) on

Friday,

> and it will have G201 (Gecko stepper drivers). My cnc mill already has

G201's

> but my first cnc lathe uses G340 servo drivers, all powered by my power

supplies.

>
> However, I haven't sold any supplies to Great Britain (yet), although my
> first lathe supply is wired for 240VAC input (just as it would be wired
> for GB).
>
> I do highly recommend the Geckos, on both the mill and this upcoming

stepper

> motor driven lathe, the Geckos allow twice the speed (up to 2 inch/sec) at
> 5 times the resolution (1/10 thou vs 1/2 thou) compared to when they were

new

> from the factory. The servo version is the same speed (2 inch/sec) but

the

> resolution has gone up to 1/40 thou vs 1/10 thou as compared to factory

new.

>
> Another solution is http://www.rutex.com from Australia, but I have no
> experience with those.
>
> regards and good luck
> Doug Fortune
> http://www.cncKITS.com