Re: Digest Number 4681

Scot,

I believe the motor power supply SHOULDN'T be regulated.

Of course, I am still building my own CNC'd mini-mill...so what do I
know. But I have built and tested the three axis Servo controller
and have tested it with the servos driving the X-Y table. I use a
36Volt unregulated supply to power the motors. A big transformer
feeding a bridge rectifier and with a big capacitor. Just what a
power supply used to look like. :-)

Jim

P.S. BTW, I use LMD-18200 H-Bridges. But I am thinking of replacing
them with my own home-brew H-Bridges.


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Scot Darr" <scotdarr@...>
wrote:

>
> I built a home CNC machine a couple of years ago but always had

problems

> with my h bridges blowing up. I was using some Lambda regulated

power

> supplies 48v @ 5a.
>
> Do you think the amplifier problem could be caused by a current

spike?

>
> Is there an equation for sizing the capacitors?
>
> Do you attach them to the positive or negative terminal?
>
> What type of capacitor works the best?
>
> I would love to dig out the machine and get it running properly.

Any

> suggestions would be greatly appreciated!
>
> Message: 6
> Date: Sun, 23 Apr 2006 23:17:22 -0000
> From: "caudlet" <thom@...>
> Subject: Re: Good Deal on surplus Power Supplies
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, wanliker@ wrote:
> >
> > In a message dated 4/23/2006 1:08:31 PM Mountain Daylight

Time, thom@

> >writes:
> >
> >Check out this neat little switcher. 48 - 56 VDC @ 5A. Built

in fan.

> >Universal input voltage (88-264VAC; 47-63HZ).
> >
> >
> >Now who has a nice little circuit for dropping the voltage for use
> with
> >Xylotex?
> >bill
> >
> >
> >[Non-text portions of this message have been removed]
>
>
> Probably can modify the switcher feedback to output the 30VDC.

Might

> be better off to find a 28V supply and it will probably adjust to

30.

> Switchers can be used but you need to hang a larger cap on the

output

> to cushion the current spikes to a PWM motor drive.
>
>
>
>
> Scot Darr
>